About 25 years ago I was the chief engineer of a radio station in Australia. We used to do outside broadcasts live from nightclubs on weekends, and we had a deal with what was then the largest nightclub in the southern hemisphere in Melbourne, Australia. For the club's opening night, we were doing a special extended broadcast to help promote the nightclub. Usually we did outside broadcasts over ISDN lines (using essentially a hardware MP3 codec at 128kbps at both ends), but sometimes we used a radio transmitter if needed. Since the club was new, their ISDN line was installed but hadn't been activated yet, and since this deal with the nightclub was worth money to the radio station a solution was needed, so we set up a temporary radio transmitter on the nightclub's roof... but as the club was huge, it was impossible to run cables throughout the club to reach the transmitter. Particularly, we needed to take audio from the DJ booth (which was high up above the dance floor), and before the club opened from a cafe at the front of the nightclub near the entrance. This would mean lots of cables all over the club which had to be tucked away and safe all night long, and for various reasons (mostly safety and the length of the cables) this was not an option. The solution was actually to use two of these devices to encode audio to video, and decode it elsewhere in the club. We dismantled a security camera in the cafe, and under the DJ booth, and joined them together behind the security video recorder to essentially make a long video line, and used this to transmit audio from one side of the building to the other, in order to reach the transmitter. (There were other problems to solve that night, such as the transmitter not being able to "see" our station building, so we had to bounce it via a receiver from a friendly TV station who then put it into an ISDN line for us, but that's another story). We used to use these devices to record the on-air programme 24/7 (as required by law) onto VHS tapes in EP mode for 8-hour recordings while keeping the quality high, before we switched to digital recording to hard disk. It was the late-90's *shrug*. I just wanted to mention it as it may be of interest. :)
I assume this is the Metro Nightclub and EON FM 🙂 Back then 3RPP also simulcast the 21st Century Danceclub in Frankston on Saturday nights. They probably used a similar ISDN system? I was slightly too young to go clubbing back then but enjoyed the simulcasts!
@@zoomosis QBH from Hitz FM. The place was a pub (Queen's Bridge Hotel) and underwent an insane renovation at the time. And yeah most places were using musicam codecs over ISDN because it was just easy, and the high price of ISDN in Australia was still justified, but there were so many problems with Telstra's installations that I knew any new site was probably not working right even if the NT-1 showed signs of life. Broadcasting from locations like shopping malls always necessitated ISDN for the OB link back in the day.
@@benespectionwas going to guess QBH. Fascinating the sorts of things we had to do back in those days to make stuff like that work. I was in tech not broadcast but there was some overlap from time to time.
I always love the niche tech genre of "playing back a recording on a device that is not intended to play back that recording". Most of the time it's just graphical garbage, but here you've got an audio visualizer that wouldn't look out of place in Winamp.
In fact somebody could probably write a WinAmp visualizer using the same algorithm which could then be recorded on a standard VHS recorder which could potentially be played back by this one
Seeing how clean the raw signal of Alec's mic is during silence and knowing that's before any sort of audio cleanup makes me appreciate how well he's set up his studio for audio.
The big blocks of white and black is likely the most significant big. The data is actually the 6 stripes of randomness. It doesn’t take much to make the wide strips stable white. You see that at 1:46 ? Most of the bits of data is to the right of big white stripes.
Once again, glad to help. Just so everyone knows why I own one... It's because of the 8 hours of record time. It's usually married to a very cheap non-hifi VHS deck and it breathed new purpose into said machine and that's about it.
@@jesseestrada8914 Because it's cheap. Reel to Reel is expensive, even cassettes are, but a 25 pack of VHS is dirt cheap and it's pretty comparable to the original signal. I'm the weird one that likes to just have music going in the background and just throwing a tape on, not needing to deal with Alexa or anything and just having tunes go.
Just to add a few bits of info to the discussion, I worked as an engineer for a local NPR affiliate from the mid80's to 2005. We used the Nakamichi version of the Sony F1 the processor to record the Oregon Symphony for broadcast. One use of the 14 bit format was to allow for more error correction, which allowed for trial and error editing on a regular video tape edit machine. Recording the audio simultaniously to the linear audio channels allowed you to jog to the approximate location, then shifting a few frames one way or another allowed for crude edits with no buffer. The PCM processor was also used for the first live national digital music broadcast (Portland Baroque Orchestras Messiah hosted by Martin Goldsmith) utilizing a satellite uplink truck is Portland to send the encoded PCM video to NPR where it was decoded and fed to the network.
I clicked on this video because it triggered a memory for me as well. In 1990, I was 13 and my parents were newly divorced. My mother's first boyfriend (he was only 24 to her 42) was as much of a tech freak as you and me. He's the one who taught me how to code and had me so far ahead of what was being taught in schools in Computer Science, that I felt it pointless to even choose that class. Anyways, I remember that he had a large assortment of his favourite music, recorded on VHS tapes, and he would play them through the VCR and the connected home stereo receiver and speakers. So yeah, I saw somebody using this for digital audio playback in 1990 :)
_"I remember that he had a large assortment of his favourite music, recorded on VHS tapes, and he would play them through the VCR and the connected home stereo receiver and speakers."_ Did he actually use a PCM processor with a VCR or did he use a Hi-Fi stereo VCR?
@Watcher3223 that's exactly what I was thinking. It makes for some nice long tapes vs c30 c60 c90 and don't have to turn the tape around for the other side. And I remember VHS tapes being dirt cheap to buy. I remember Christmas around the late 80's early 90's we would be given cassette tapes and VHS tapes.
This is why Sony and Philips both initially only advertised the CD as being able to hold "one hour of music", not its official maximum capacity of 74 minutes -- because that's the longest length of U-Matic videotape that was available at the time.
Curiously, Sony and Ampex later released U-Matic cassettes with a thinner tape and longer length (Sony MDU-75 and Ampex/Quantegy DAU-83E respectively). At the same time, full-length 74-minute releases ceased to be a rarity.
The alternative story is that the duration of a CD was set by the Sony President as it had to hold a full version of the Beethoven's Ninth Symphony without interruption
There was another use for these units. They would be used for high quality recordings of legal matters such as depositions, board meetings, etc. The long time runs and archival quality were very useful.
I was wondering about this. Such people would certainly be interested in the high fidelity, but not necessarily need a professional-level product, just a consumer level.
@@dracodis I don't think the high fidelity would matter that much. However, being a digital recording, if the 0s and 1s turn into 0.7s and 0.3s from age, all you need to do is re-record it and your audio is safe for another couple of years or decades. If that happens to an analog recording you're f'ed
@@bene5431Ideally, you should run it through error correction each time making a copy, thus avoiding dropouts to accumulate over the copy generations . Using the smooth-out processing to fill in unrecovered holes is more dubious, because guesswork is guesswork .
Years ago a friend of mine just had to let me know that a local FM radio station that had been first to play CD’s was starting to play music from digital audio tapes. My response was ‘so now we can listen to a little bit of disc and a little bit of dat!’ (insert rim shot here).
After Tom Scott's video, I was really expecting a video from you about how climate control in hell can be surprisingly affordable if you use a heatpump.
Tom also mentioned having to leave the vial of Hell dirt with Alec since he couldn't bring it into the UK. I was really hoping it would have made it to the prop wall and would have been an Easter Egg hidden in plain sight for a year.
Thanks for the video :) Some notes: 03:17 - in context of this video, cheaper 14-bit PCM adapters were using only ONE chip - DAC. ADC conversion was made with the same DAC chip and some analog circuitry (successive approximation ADC). 10:10 - one line contains 6 x 14-bit audio samples, 2 x 14 bit error correction words and 16 bit checksum, 128 bits in total 13:50 - look for "STC-007" or AES 28-4 or US4459696 patent, that's STC-007 standard 15:28 - each next 14-bit word of the source is shifted 16 lines down, that's why patterns appear to be slightly diagonal 25:27 - yes, you can, any STC-007 adapter would read it 25:56 - because 14-bit is the standard (STC-007) and 16-bit mode is Sony's hack on it (starting from Sony PCM-F1) 26:12 - no, PCM-1 used its own, Sony-proprietary encoding format, 12-bit static resolution (14-bit dynamic resolution) 26:26 - VP-101 uses standard STC-007 encoding, compatible with 14-bit of Sony adapter (and not compatible with PCM-1) 26:39 - yes, SV-P100 is a STC-007 compatible recorder 26:53 - yes, that would work both ways 27:53 - exactly, 16-bit mode was a Sony's hack, re-purposing one error-correcting word for 15th and 16th bits 28:02 - indeed, 14-bit mode can withstand loosing 32 consecutive lines without an error, 16-bit mode can stand up to 16 lines only 31:13 - STC-007 PCM data also has more data than just audio, it contains 128 bit/line, that gives 128 x 490 lines x 30 fps / 8 bits = 235.2 KB/s, or 235.2 x 28800 s (T-160 SLP) = 6.77 GB edit: fixed measurement unit
I remember from my time as a digital tape recorders technician that 16 bits ADCs were not very accurate (12 bits had +/- 1 bits accuracy while 14 and 16 bits were worst, leading to some "distorsion".) That was not relevant for sound recording, as it offered better signal to noise ratio, but was when it was signals from sensors where accuracy was more important.
Wow, it's really great seeing people who know their stuff in the comments! I don't, to be clear, not on this topic, but I can see that if I wanted to make an even deeper dive, your notes would be a good starting point
You didn't need a recording studio to need high quality recording. There are various live venues (churches, etc) that might want a recording. It's best to capture it at high quality so you had room to process it before dubbing it onto cassette, or maybe a custom run of records. For some it may have been a hobby. (Never underestimate the money people will spend on a hobby.)
I follow the same rule with modern digital media. Always get the highest possible quality version. You can transcode to a lower quality if needed but not a higher one, and every conversion between lossy formats reduces quality further. Though, I had to tell myself it's a bit silly to store full-resolution PNGs from a flatbed scanner... Cropped JPEG is usually good enough there.
Yes, exactly. As a specific example, over a span of about 20-25 years or so, my dad used to make recordings of every performance of the chorale group he and my mom were members of. He started before these PCM adapters existed, never mind consumer VCRs, so he was using open-reel tape decks, and then duplicating the recordings onto cassettes for people who wanted a copy. But in an alternate history where he started doing this when these PCM adapters were available, I could easily see him having chosen this tech instead, for its suitability as an original source for repeated duplicates and higher source quality. An added benefit would be that the archived material would probably degrade a lot less quickly than the analog option would. The analog tapes could wear out over time and without any error correction built in, the duplicated copies would get just a little worse with each copy. Not noticeable for dozens of iterations, but it probably could add up for larger volumes. I'd guess the digital audio made with this technology would hold up longer, and it would be easier to make perfect backup copies, which could be used to completely eliminate any problem of degradation over time.
I don't see it so much as a "consumer version" but a "consumer-compatible version", the kind of thing maybe a small campus radio station or in your example a church might make use of. Admittedly, I haven't tried to look up the historical price of a professional Betamax recorder vs. a consumer VHS VCR, but I'd expect the difference to be enough. I imagine it also would have been easier to run down to Sears to get a replacement if something broke, vs. dealing with vendor/distributor service, if the setup is made from "consumer-grade" hardware.
@@pshalleck I think you're describing "prosumer". True professional would have balanced line level stuff, but the prosumer would be happy enough with RCA jacks.
When I was in high school, I worked a part time retail job that used this system in store. It was used to play the store's music throughout the day thanks to the long play time. Every week, head office would send a new tape with that week's mix and in store messaging. Interestingly, that chain was a distant offshoot of Sony. Thank you for tackling this system! I knew that using vhs for audio was done. Thanks to this episode, I now know how it was done.
This ^^ You could have hours of music on a single tape. It was great for parties if you just wanted to press play, rather than have someone manage a playlist of vinyls.
That's a really clever and weird way of doing BGM, I've seen plenty of Techmoan videos of such machines and their unique physical formats, sometimes just hacked up consumer stuff, but didn't imagine people using the method you describe. This reminds me I've read about Video 8 also being used in that way for a heck lot of PCM audio runtime as well, likely about the same method.
I once was sat at the PC by my friend who had a birthday party - he asked me to manage the playlist that evening. It was one of the happiest evenings of my life, since his friends-musicians approached me here and there to ask for the name of the song. But it is different from changing the records all the time, I get it.
The throwaway line about piano being digital threw me for a loop. I'd never thought about it but player piano rolls are just punch cards which are digital data (as are music boxes). That realization is fun.
We used them for recording masters for a classical music label (orchestral, solo, chamber) They could then be transferred to tape and edited (digital editing was a little out of reach). Amazing sound quality and completely ‘professional’ quality!
Fun fact: This was how I used to record at music festivals for a very long time. I would record onto the stereo hifi track as well as through a PCM. I still have my Sony F1 PCM and can still play back many of the archival tapes I have (though a huge portion of those have been digitized at this point).
Moved to a PC file format, actually. Because it's digital audio already, isn't it? I'm curious about the process, how do you copy the tapes onto a computer??
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@@asnovasdodia There are PCM adapters which have S/PDIF connections (eg. Sony PCM-601). Otherwise you can also re-digitize the analog output once again. To be fair, that's still give going to give you excellent audio if done right.
I always wanted the pcm module for my F1 system & never got it but I still have all the brochures for the F1 system I would have liked to have the rest of the F1 system as well I could only afford the VCR & camera
A work colleague recently told me that back in the late 90's when all night raves were broadcast over FM radio he used to digitally record them using his Akai VCR. He wanted to record the entire session without having to stay up swapping tapes so would set a timer and go to bed, then in the morning he could listen back to the entire 8 hour session.
If those were recorded on a VCR that one might have at home, you were using the analog audio section of standard VHS tapes. Many of those had a compander circuit in them and at best would sound like a cassette tape with poor noise reduction.
@@jimmyklane thus, why the OP specified an AKAI brand VCR. They specialized in high quality audio equipment. They are actually most famous for reel-to-reel tape recorders. Why would you assume they used a "typical home" VCR anyways?
@@squirlmyYou’re correct, I did make an assumption however it wasn’t a completely uniformed one. I’m a musician, I’m familiar with (and an owner of several) AKAI Professional products. In the 80’s they made consumer products and VCRs were some of those products. I’m not aware of (although I’m not claiming a comprehensive knowledge base either) AKAI making any professional level VTR/VCR products and presumed a consumer product. Upon a second reading of the post I replied to he does say “digitally recorded” so maybe he remembers it being a professional level product and just didn’t specify. I don’t have a need to be right lol
A friend of mine had this. He used it to record his band live (long sets). But what was really cool (and you should have mentioned!), is that you can still record on the analog audio track of the VCR! So my friend would record the stereo board output to the PCM system and record a mic from the audience area onto the VCR’s analog audio track. I can’t remember if he had a stereo VCR or not at that point. Great video as always!
Don't forget some late consumer VHS VCRs models had Hi-Fi audio option. The same audio was recorded on tracks at the edge of the tape and the same was recorded in Hi-Fi (on the same area as video data!). The Hi-Fi equipped VHS player read the better audio recording available on a tape.
This brought up memories. My old piano teacher would use a Betamax and a PCM adapter to record concerts of traveling musicians. Or of student performances (many of his students went on to professional careers in classical music). I always thought it was so neat when he’d pull out a video tape and play back ridiculously high fidelity recordings of the piece he had just assigned me to learn over his giant Marantz horn speakers.
I suspect that those may have been Klipsch horn speakers, they may have also been Altec A7-500 speakers, I'm pretty certain that Marantz never made horn speakers.
I used one of these back in 1986 to record live classical concerts. Worked like a champ. It was how we had to do it. No more tape hiss though which then caused us to go searching for a solution to the next weak link in the chain. So that caused us to look at new microphone preamps and new mixing boards. It got expensive before it was all done. And it was great for live classical stuff where a stereo recording was fine. But modern and pop music wanted more tracks than just two. The race was on.
My step-father played in a band that played a wide variety of music on acoustic instruments. They played in a lot of cafes and small bars, and often when they began unloading their equipment that manager or owner would begin to look hesitant as if he thought their act might not be a good fit for his venue, and my stepfather would take a moment to explain to them that their quest for a sound system that would amplify their voices and instruments without introducing a lot of noise had unfortunately led to them buying a system that would let them play in stadiums. Do not be alarmed by the speaker towers taller than a human, or the mixing board mounted atop a rack of amplifiers the size of a dishwasher, it's all there to make sure that the mandolin comes through crystal clear.
You see a similar problem of live music vs your system in your home. Yes, both systems will comfortably play over 105db which is plenty loud. My home system has over 5kw worth of amplifiers even though they rarely go over a couple hundred watts. But they get to that couple hundred watts real damn fast so you get that live music thump. You also don’t get A the music fatigue of listening to loud music. Your peak levels are high. Your averages are lower. So you don’t get the ear fatigue.
Yep - I knew an organist who traveled around playing different instruments across the US and Europe, recording on a portable PCM + VTR back in the 80s. He'd take the tapes back, edit them down and publish on various classical labels. Just him and his gear - made for a low cost production.
Back in the day I used to store Amiga programs and data on a VHS tape recorder, using a SCART to RCA cable and an interface I built. Damned if I can remember much about it now.
It was tfe VBS. Video backup system. It was heavily used by swappers. I remember i used one back in 94. And at that time it wasn’t new. The best part was that the amiga stock config could outpu composite video w/o extra hw. We just needed a scart with a resistor ladder hooked up to the parallel port
The Amiga VBS couldn't handle as much data as the PCM or PC interface but it's just one cable and the software displayes the name of the stored data next to it - which means less data but you can *see* what you're looking for (on VCR).
Before I got my Amiga, I had an Amstrad CPC 464. There was a local radio station that - I kid you not - once a week sent software over the airwaves to be recorded onto cassette and then played back in the Amstrad's tape deck for loading 😂 It was magical. This was one advantage the Amstrad had over the C64 - copying cassettes was easy with two tape decks.
or a regular audio cassette tape ... like Atari, Texas Instruments, or Tandy (radioshack/realistic). You could also build one with a kit from Sinclair ... my first computer. I'd say Commodore too ... but that was after the shit show between them and Atari. Atari was an Amiga ... they had the rights first. What an interesting war they had lol. Mutually assured suicide.
Oh my god a Digital Equipment Corporation shirt!!! My dad worked there from basically the day I was born (in the late 80s) all the way up until its tragic demise in 1998. What a nostalgia bomb.
I recently obtained a Digital Equipment branded rolling computer workstation from a thrift store. It's built like a tank and is filled with VHS machines and audio gear for stupid audio fun. I had to have it.
@@swisspeach67 A fridge sized case with huge swappable cards for various features (cpu, cache, memory, drive controller). Mini because transistors fridge computer is small vs a room size tube computer.
That recording time seems key. Maybe this was intended as a prosumer device for recording concerts? There are countless venues which routinely generate hours of live audio, but don’t necessarily have the budget of a professional studio. Something like this might fill that niche. (Whether it was actually _adopted_ for that purpose is another question...) *UPDATE:* I now see that the comments are flooded with people who used this device for _exactly_ that purpose. I choose to frame this as validation of my incredible powers of deduction!
@@spugintrntlit would also be a decent item for small time pirates to get music and sell it undercutting any stores selling offical music, good enough to sell, not so outrageously expensive you'd never get a ROI
When myself and a bandmate took our master tape to Fantasy Records in 1988 to be mastered for our record, I was surprised when they gave us a VHS cassette back; it was the first I had heard of the technology...
How a guy can take a subject I (and maybe a whole bunch of others) have absolutely no interest in or recollection of and make it into an interesting learning experience and history lesson as as hold my attention for 30 mins is beyond me. Well done sir, I guess this is why I watch your channel, you're the cool nerd kid down the street. Cheers. Oh BTW nice T-shirt!
My father was involved in the progressive rock scene in the late 1970s and early 1980s and he mentioned this type of devices being around in his circles back then. It did come in quite useful for the not quite professionals, but still ambitious hobby musicians in that era.
In the early 80s, Mobile Fidelity Sound Labs actually sold pre-recorded albums on VHS and Beta that were designed to work with PCM adapters, making them some of the first commercially available digital recordings.
The Boston public broadcasting system affiliate WGBH (VHF 2) would broadcast classical music on its WGBX UHF channel 22. The video portion of this classical music broadcast was *exactly* this black and white PCM video adaptor output. Presumably, you could feed the WGBX music broadcast back into a PCM decoder such as the one in this video, and hear the classical music in "almost CD quality". Hey, two years ago, I found some information about Sony's 1970's PCM adaptor bit formats and error correction codes. I know which book it's in, I just need to dig it back up...
Imagine in 1975 you could just flick on your PMC insert an album casette and listen to some music in essentially perfect quality, at a time where radio was scratchy and vhs sounded like a tincan. Sony really dropped the ball on this one. They had the hardware, they had the tech, all they needed was to iron out some kinks and get some studios to release their music in their format, it would have been a huge success.
This brought back some memories. At BBC radio, we used this to live transmit classical concerts from around the UK in the 80s. A PCM-F1 was used at each end of a standard TV circuit, expensive but worth it for a high value concert. This gave great stereo sound and as the classical network used no audio processing, the quality on FM was superb, albeit limited to 15k at the top end by FM. The system was also used to play back concerts off a Beta tape, although cueing it up and playing it in live was always somewhat scary! The PCM-F1 encoder and matching Beta machine were beautifully made and small enough for both units to fit side-by-side in a rack width.
I imagine that reserved satellite channels were occasionally used to distribute such transfers to a large audience across the world. I certainly was entertained to realize that most of the shows I watched were actually transfers intended for the stations to pick up. They'd always have cards where local advertising or announcements were supposed to go. To think, I probably saw some of this audio back then and thought I was just looking at static!
My dad worked in a shop for twenty plus years and one of his coworkers had converted his collection of hundreds of records into over a dozen 8ish hour mix tapes on VHS tapes for the shop to listen to while working; they'd just have to pop a tape in in the morning and be good for most of the day. My dad always said the quality was amazing too and he couldn't believe it was coming from a VHS tape. Knowing that the guy who did that was a massive audiophile I'm now fully convinced he had a setup like this back then. Super cool!
It's probably more likely that he was simply using the regular analogue hi-fi VHS audio. That was good enough that it was widely used in British radio in the 80s and 90s for 24/7 radio station output logging; a few domestic VCRs using standard VHS tapes available anywhere were cheaper, more convenient and higher-quality than a couple of specially-modified open-reel audio recorders running slower than audio cassette speed (which was the previous standard way of doing it).
Just a few notes: Engineer Roger Nichols said some satellite TV companies had music channels, sending digital audio over video signal. 14-bit DID allow better error-correction. I remastered an album that had both a 14-bit and 16-bit version of the same mixes on the same tape for added safety. I knew a guy who did live recordings with a HiFi VCR; using the analogue HiFi channels and a 501es to get another pair of tracks onto the tape. Fun stuff!
I just spent some time acquiring a PCM device to retrieve recordings made in the mid 1980s. The tapes were made with a portable Betamax machine to record performances in Bali, Indonesia. It was essentially used as a portable recording studio. I have a friend in Vermont who recorded concerts the same way. These devices allowed many audiophiles to make field recordings of very high quality. The RCA inputs were just fine when connected to a portable mixer. I also know of a professional audio studio that used this format to back-up their digital recordings. BTW, the tapes were mostly flawless after nearly 40 years.
To your point, back in the 1970's, we were using what were essentially portable cassette recorders to record and store data (programs) but the need for random access to data was far greater than the need for large amounts of data so early floppy disks and hard drives were of far greater value than any medium that could store vast amounts of (then nonexistent) data. I always enjoy your extremely well researched videos and trips down memory lane. Thank you.
Even our Commodore VIC-20 had an audio cassette deck for storage, though of course it was painfully slow. I believe it worked with the C-64 as well, though by then we had fancy 5.25" floppies. A friend told me his family had a similar setup for their Sinclair, and that cassette deck had a tuning knob for drive speed. Apparently for one of his favorite swapped games, he had to make precisely timed speed adjustments to get it to load. 😀
Broadcast engineer here. The PCM on NTSC was fascinating. I could see you going down the rabbit hole of Nielsen audio encoding. There's free software [NACAT] that allows you to run against anything playing on your computer and it'll decide the ID numbers coming down the stream. It's fascinating as it's basically subliminal in a sense. That's about it though. I live in Indianapolis and have plenty of demo gear we could make work for something if you're interested
Years ago I was at a nightclub doing video recording of unnamed blues piano player and guitarist, there was also a guy there with one of these devices putting the audio onto a Betamax, he was recording both Digital and analogue. This was back in the 1990's and even though I had access to a Cable Access studio with a lot of high tech gear for the time I found this guy's setup nothing short of amazing. Thanks for the reminder, of that time I had a lot of fun shooting video in that club and got to meet some absolute blues legends.
The 8-hour recording ability has me thinking if one target market might have been non-audio-production commercial (ie, a whole working-day's worth background music for a shopping centre, assuming they even did that back then). That grey area between home users who don't need as much, and the pro users who need more.
I think that it could have been an alternative to reel-to-reel tape for home use. A recording time of 4 hours (at LP) would have been great for home use. A problem with using EP/SLP is that the video tracks overlap by a third on the right and left sides of the track, leaving only the middle third clear. With LP the tracks touch but don't overlap, and with SP there's a space between the tracks.
I just want to say... as a 22 year industry veteran, starting just after the dedicated engineers who studied on the job and had degrees and such, I learn a lot about my industry and my work on this channel. I work with PCM audio daily, and only just now knew about it's history and details... thank you!
Yeah, I deal with PCM too, though I'm somewhat new compared to you in this industry (15 years working with audio). That was an interesting history lesson. It would be great if he talk about other devices like this in the future. ADAT is nice one, and it used S-VHS tapes.
Still using a 1980's Onkyo in my media center. My modern TV can still connect to this stereo without special adapters because both units have an optical port and the TV still supports PCM output sadly if you try to use any dolby encoding the stereo just buzzes loudly
I actually didn't get the joke until you called it a Dad joke. I thought he meant you could record piano music on paper tape and play it back again, like was pretty common in the 1800s 😅
Yeah, piano rolls were basically digital music, albeit with a very low bit speed. But, he's talking about music on a piano, played with your fingers, or digits.
I think I've told this story before, but in 1978ish, I recorded the medium wave band on my VHS - all of it - as an analogue signal. Next up, I took the undemultiplexed FM signal from half way through a tuner I was building, stuck that signal in the video in and recorded that too. Brilliant hiss free stereo when I fed that back in replay through a demultiplexer. Yes, I did it partly because I could, but also to record a 6 hour radio broadcast of a concert I was at. How did I lock up the tracking you ask? Well, I took sync pulses from a Pong gam and fed them in to the right place on the VHS PBC. Yes, it did go click click click - but not too disturbingly !
I understand that the video signal of vhs is about 6Mhz, but what device did you use to shift the medium wave band down to baseband? Did you make something yourself?
Nope. The bandwidth was nowhere near 6Mz by the way. Broadcast TV was 5.625 MHz, a VHS cunningly squashed TV in to just over 1 MHz. I just stuck the wire in the hole. @@JT-bb9di
@@JT-bb9di No need to shift it. The video bandwidth is just over 1Mhz, not 6, if it were 6 it could do the 5.625 MHz full broadcast composite colour signal, (I was a PAL BBC VT engineer). I just stuck a long bit of wire in to the video in on my piano key VHS. Same frequency - no shifting needed. I got lot of click though. I had to create a control track to make the heads find the tracks on replay. I used a 'Pong' game as a video sync source :-) I thought it up one night and got it working within about one and a half hours.
I'm sure someone has mentioned this but these were big in the "Taper" community, and people used them to record Grateful Dead shows. I also believe I've seen reference to the F1 PCM unit being used for on set recording films since you could pair it with a luggable VCR.
@@denelson83 - And since we all know what he meant... was it necessary to point that out? Really? OK. Thank you for not beating us with the ruler Sister Mary Denelson83 LOL. Transgressions in school used to be severe... You must be having flashbacks.
28:54 There were actually some pre-recorded PCM videotapes released by the audiophile label Mobile Fidelity Sound Lab back in 1983, on both Betamax and VHS, with the big album they released on the format, of course, being "The Dark Side of the Moon", as it seems like every new audio format needs to have DSOTM released on it (and for good reason). They also released other albums like "Crime of the Century" and "I Robot" on the format as well. However, they haven't appeared to have released any other albums outside of the initial releases, and hell, while Discogs does have a category for the format (as "Digital Audio Cassette"), featuring a picture of an ad which listed their releases, the only one the category actually lists out is a Beta release of DSOTM, so you can assume that the line didn't last too long (this was the same year the CD launched in North America and Europe) and the tapes themselves are incredibly rare (according to the Discogs listing for DSOTM, only around 100 of each release were produced).
This should be implemented as an input and output format in ffmpeg. I would love that. :D (Edit: on a more serious note, a good video capture of such a source tape would be much easier for most of us to do than to get hold of a pcm-adapter.)
Excellent end of term project for a heterogeneous parallel programming class (often NVIDIA CUDA) or a GPU hackathon. For big bonus points, transcribe from a 4k video stream taken by a handheld cell phone pointed at a video monitor playing the stream from tape.
There is a software project called SDVPCMdecoder for decoding video files back into audio. I don't know if there's something that would work in reverse, but... maybe.
There is already software to do this, but the capture needs to include lines at the very top which most capture devices miss out. So it's not as simple as it seems.
When the Bose wave "boombox" came out, they had a show at the local store. Since the whole demo was about sound quality, the demo was played back on a PCM machine. They also used a large number of slide projectors instead of movie film for the visual. Quite the show.
I think one reason home computers didn't really see this type of videotape storage is the almost impossibility of accessing random data if it's not close to where the tape head currently is with the system. It's okay for large backups, movies, and continuous audio... but anything else quickly becomes a nightmare. You'd want to store these gigabytes of content somewhere else so you can use them, and that was still a difficult problem like you've mentioned!
Tape cassette-based backups to back up your whole hard drive was not uncommon back in the Windows 3.1-ish days. I suspect the tapes were higher quality than your standard VHS though, and it was around when hard drives were in the realm of hundreds of megabytes.
Yes that's true. Without a control system for the deck, something that wasn't standardized on consumer VCRs, it is not practical for random access. Back in the 90's I remember there was the Video Backup System for the Commodore Amiga made by Lyppens Software Productions, a neat product intended for making hard disk backups to VCR. I don't think it sold very well and was basically killed off by Iomega's Zip Drive.
One reason digital tape was not very popular with microcomputers of the day was that it was very difficult to deliver (and to process) the sustained stream of data (at about 1.5 megabits/s) in the microcomputers of the time. When using a card and a VHS recorder, you would really need to keep up with the speed. When using DAT tape (recorders were available for computers, these were in the half-height 5.25" form factor and lacked the audio part), a common problem would be that the data was not provided quickly enough, and the drive would stop, rewind, play until the end of the recorded data and then go back into record mode to write data until again its buffer would become empty and it had to stop again. That constant back-and-forth shuttelling was bad for the mechanism and the tape, and it dramatically increased the time to record the entire tape. This problem in fact still exists today. Over time, capacity of backup tapes has increased a lot, and as the time to record the entire tape has remained about the same, that means the datarate went up. On a modern LTO-9 tape with capacity of 18TB, the datarate is 1000MB/s. That still is difficult to sustain over an entire backup run.
As a follow-up to this, you've *got* to take on the oddity that was D-VHS: digital audio (even Dolby Digital or DTS tracks) _and_ digital video (up to 1080i!), all on a video tape! Truly a versatile piece of consumer physical media, provided you had the codecs to support reading or writing to the tape. It could even be an interesting segue into the early DVR days of television - PCI cards, MPEG-2 codecs, Firewire ports on cable boxes, W-VHS for Japanese MUSE television, you name it. A little less unique than recording digital PCM audio into a composite analog video signal, but you've spent so much time on the various quirks and features of VHS and Beta both that a video (or series) covering the later years of the format would be welcome content.
It's mind blowing to see the capacity: up to 50 GB. Yes, a dual layer BD. On VHS tape (I think it uses S-VHS formulation or was it a tiny bit better?).
After seeing how densely the data had to be packed onto tapes just for this, I wonder if D-VHS required finer-grain tapes than standard VHS, and the only real similarity was the shape of the cassettes (and the players being backward compatible).
@@stevethepocket From memory, S-VHS metal particle tape (so finer grain) and of course, we're talking about stuffing extra reliable digital data into possibly terrible quality 240 line video signals here, vs. D-VHS that doesn't need to deal with any of that NTSC crap after all, this whole deal is quite similar to dial-up, having to piggyback on the limitations of a medium and use it in incredibly ingenious ways, D-VHS tho doesn't need to care about the piggyback stuff, being way closer to the jump from Video 8 then Hi 8 and finally Digital 8. Digital 8 uses the same tape as Hi 8 to store quite a few gigabytes as well.
@@stevethepocket That's interesting indeed, and several different variations exist. I do know that helical scan systems like VHS, Beta and all the common video tapes are common, but so is LTO nowadays, which just as the name suggests, is linear instead, with several tracks parallel on the tape. Now, what they physically do to have tapes up to several terabytes, no idea.
I remember the days when nearly every recording studio control room had at least one Sony 5800-series 3/4" video tape deck in the rack...and remember that there was (nearly) no limit to the number of dollars a well-heeled audiophile would spend for the perfect audio recording/ playback. The Japanese electronics industry has a record of answering the question nobody was actually asking. This is a curiosity, and and rather prophetic how it merged the computer data world with that of audio purists.
I still remember the first time I disassembled a VCR player. At that time I was about 14 or 15, but I already had enough knowledge to be able to disassemble and reassemble it without damaging anything, and I remember it blew my mind. The mechanism, so beautiful! I remember inserting and removing the tape several times just to watch the mechanism pull and return the tape into the cassette. Actually, I was able to improve the audio quality. Since new, I noticed the audio was a little weird compared to other VCR players I knew. When reassembling mine, I found out that the audio head came misaligned from factory. This player lasted for several years at home before being replaced for a DVD player. Nice memories!
I was lucky enough to be given a "broken" VCR to take apart. Not only did I learn about the fascinating mechanisms, I discovered that it actually worked just fine!
29:56 the lack of random access was the issue. Same reason why tape disks today aren't consumer devices. Most data you don't access sequentially, only video and audio.
Alec, Another great video. A couple of notes about Sony consumer PCM adapters. The Sony PCM-F1 adapter was released in 1982 along with the SL-2000 portable Betamax recorder. Both could take an NP-1 battery pack and allow portable digital audio recording, the F1 also included microphone inputs, and semipro recordists often hung that pair off the end of a Tascam or Yamaha mixer and made digital recordings of events. They were also used by record companies to make copies of master tapes for distribution to artists and label execs.
I was looking for a comment like this. I am wondering if most of these were used a a semi-professional context like sending preview tapes around to people who did not have any other reason to have the professional equipment.
No one seems to appreciate the linux 'cat xyzzy.jpg > /dev/audio' thing as much as I do. ...and while it's true that I've never done that (it sounds bad and you can bork your speakers), I love that you *can* do that.
Here's a fun thing you can do with digital data. Databending! If you convert a picture, any picture, into a .bmp, then open it as a raw binary file in Audacity, you can then add sound effects like reverb, echo, phasers, whatever you want to the "audio", then export it as a .bmp again. As long as you don't mess with the header at the beginning, you can create some really neat distortion effects.
Back when I participated in the Java 4K Game Programming Contest, someone got the bright idea that "hey, couldn't these be shown as images?" So I wrote a program that turned any 4K or smaller game into a PNG file. Initially in black and white, later color. Then I made a launcher that could read the images directly and launch the program. Before you knew it, all the games were encoded as images which were being passed around for fun. And that is what happens when you get too many geeks together in one place... 😂
The piece de resistance of Sony's line was their famous Sony PCM 601 ESD, which had a SPDIF (Sony/Philips digital interface) so you could copy the digital stream to non-videotapes.
Music Producers used these a lot in the early '80s, to preserve audio fidelity with multiple copies/versions of mixes and recordings. Popular with remixers
My mom worked for Digital Equipment Corporation for most of my childhood so seeing that shirt brought a smile to my face! As a consequence of her working there, I remember seeing a VT100 hanging around at her office. As an IT person now myself, it's cool to me that we still use VT52 or VT100 emulation for terminal software. I think I still have my first computer which was a Digital PC. Thanks for the inadvertent trip down memory lane!
I really love watching your videos, as someone whose done Sound Design, Video editing, music composing, and everything in between, I appreciate the rich history that audio and video have! Also, I watch your videos at a faster playback speed, but still fully understand all the information, so I don't mind the longer videos! Please keep making great content and rich history videos! :D
These were used sometime in the 80's by BBC Radio for some onsite OB recordings, usually classical music. IIRC they replaced digital reel to reel recordings (made on, I think, Mitsubishi?) that had to be replayed in the OB truck in the studio centre carpark. Recordings were made on Beta and replayed on a C9/701 unit that lived on a trolley that was wheeled into the appropriate control cubicle. I've also got a vague memory of them being used for live OBs that had a video link out of the venue.
I'm glad you posted that story, because I remember being a new engineer in BBC News' Spur Central Apparatus Room (SCAR) around 1983 and seeing that unfamiliar signal coming through our switching centre and being told it was a Sony F1. I only vaguely remember that it was an OB from somewhere!
@@mattgies Outside Broadcast. Nowadays a quality audio recorder can fit in a pocket, but then they were big and heavy, Google "Mitsubishi X-80 or Studer A80". It was permanently mounted in an OB van. When a concert was recorded for later broadcast the mixing desk might be set up in the venue and it's record output tielined out to the recorder in the van. Network Radio didn't have an X80 so the broadcast would be repro'd by the van/truck in the carpark and tielined to the network continuity suite (master studio). Once concerts started being recorded on Beta it was easier and cheaper to keep a dedicated repro machine at base.
You should do an episode on trash compactors. Where did they go? I grew up with one. It was amazing. Actually, I hated it when I was young because I had to take out the heavy garbage. But I know I would love it as an adult. I feel like a lot of younger people don't even know we use to have them.
We have one of these Sony devices to record up to 15 analog data (DC-5kHz) channels via a multiplexer. It is from the USA so requires an NTSC video recorder and 240-110V power supply converter. And there are two audio channels too. Works a treat. Replaced an earlier Australian-made 4 channel unit using FM modulation onto a 4 channel reel-to-reel, which dated back to the late '60s.
Minor point about CRC - CRC is error detection, not correction. You need some type of ECC, like a Hamming code, for that. Reed-Solomon is a newer one (but not that new - it's used on CDs), but probably too complicated and too late for a device like this.
I worked for Sony's short-lived Pro Audio division back in the 1980's. We developed a DASH system (Digital Audio Stationary Head) that used a 24-track audio deck to lay down digital audio in stereo. This would be used for mastering an audio mix in a professional recording studio. It used Reed-Solomon coding to take care of error correction.
@@geoffhetzel9691 Yeah, Reed - Solomon was invented in the 60's, so it makes perfect sense stuff from the 80's would use it, including CDs (the first CDs were introduced to the market in 1982, so most of the key product development was probably late 70's). But, as was mentioned in the video, some of these PCM devices date to the 60's and appear to be compatible with the newer ones. Theoretically, they could have use Reed-Solomon since I think it did predate the earliest units he mentioned, but it would be a tight fit. Hamming code is alot simpler and was invented in the 40's, so it's probably a better candidate, given the electronics of the day and product development schedules. It's also possible both were used. Perhaps the earlier 14 bit ones were Hamming and the later 16 bit ones were Reed-Solomon. That would actually make alot of sense - new products, like CDs or your DASH system, are rarely truly new inventions, but instead incorporate lots of earlier work. Like you say, Reed-Solomon encoding is very widely used. Apparently we haven't found anything massively better because it's still getting incorporated into standards like DSL, ATSC, DVB, Blu-Ray, and many others. It was even used on the Voyager probes.
That was very interesting. When I had a job as a teenager from 1995 to 1997 as a rapper and clean up boy in a meat department of a grocery store, I did have some cutting duties but it was the wrapping machine that fascinated me. It was likely from the area you are describing and it used an audio cassette to digitally feed each week's prices for each product into the machine so that when we enter the product code it priced it properly. I remember observing my boss programming and audio cassette in the office where they had the device to put in price data and converted to an analog cassette tape and then loaded on the machine in the Meatpacking room. Quite fascinating and I never fully understood how it works but now I do. I've been a lurker up until now but I really appreciate your content!
What a coincidence, I just found a bunch of recordings (almost 28 hours!) someone posted on TH-cam from Live 105 KITS from 1989-1990 that was recorded using PCM to a VCR. There wasn't much info that I could find about "PCM adaptors" on YT (or I wasn't looking hard enough), and about a week later here you are with a video on the exact subject I wanted to know more about. Awesome!
Love the visual aid of the screen on your desk displaying your mic input. Your productions are always as enjoyable as the text of your videos themselves.
This reminded me of my habit to record LOOOOONG (6hr+ nighttime) radio shows to VHS in LP mode, because the audio was far better than anything we had back then.
I remember a friend in a band during the early 90s had one of these he got in 1989. Was amazing quality. I remember playing one of the VHS tapes out of curiosity and seeing the block pattern like you showed. He also called it a PCM ... I just called it an ADC-DAC. I didn't realize these were around much earlier than 1990. These were NOT cheap either. $2k in 1990 was a lot of money (over $4k today)!
8:47 _"That might look like a bunch of black and white dots to your eyes, but to the right circuit, that looks like bits"_ - I'm reminded of PaperBack by Oleh Yuschuk (of OllyDbg) that let's you back up files to paper by printing them out as small binary squares, then you can recover them by scanning the paper backup and running it back through the program (essentially giant QR codes before QR codes became ubiquitous after smartphones became a thing).
The "shuffling the data around" approach is used in deep space (and presumably less deep space) communication encoding too. The idea being they characterise the sorts of 'damage' that normally occurs to a signal and find it is often time-limited. So, you shuffle the signal and spread the 'damage' such that each error correcting section gets fewer bad bits, and the maths (Hamming codes) can recover the bad bits per section. You then un-shuffle, and hey presto, the original data. Compare to it being perhaps easier to fix five small holes in your tires than one giant hole.
We used 'Digital tape recorders' (Multi-track) in 1989-1993 in a few pro studios I used to work at back in the day. We produced a few famous albums back then. Thanks for showing this idea to today's inhabitants. Stay adaptive and creative, folks. Every age has problems that need simple, cost-effective solutions. "Water seeks its own level / Lightning always takes the easiest path" (Development/Marketing/Consumer truths)
You should do a video on samplers from the 80s to 90s. Love that this is something that can be done with a VCR. It's insane. Could even be a capture card potentially?
There actually were official pre-recorded releases on this format, believe it or not. Mobile Fidelity Sound Lab (MFSL or MoFi) made a few back in the early 1980s for the audiophile consumer market (on both VHS tape and Betamax tape, depending on what the customer wanted). One of the albums they released on this format was Pink Floyd's Dark Side Of The Moon, which is probably the rarest official release of Dark Side Of The Moon ever released (I would say "most sought after" but truth is I dont think most collectors even know it exists, because most collectors focus on vinyl only still). MFSL didnt mass produce these of course; they were made by hand whenever someone ordered one, and probably less than 100 copies were made of Dark Side (and who knows how many of those have been tossed in the garbage in the years since by someone cleaning out the estate of a dead relative and just discarding it as "some old vhs tape"). This was in 1983, so may well be the first digital release of this iconic album; the first CD release of it was also in 1983 (in June), in Japan, but Im not entirely sure of the timeline on which of the two came first. Would in any case be very interesting to compare the two, both in terms of just sound quality, but also comparing the masterings.
@@zoomosis I often muse about how much changed in 10 years in the last century, in terms of how things age technically; whereas in this century we have still have breakneck technological change, but the style and technical depth of music hasn't really changed much in the last 20 years at all.
Can you imagine people's faces, when you show up at an audiophile meeting with a crusty old BetaMax recorder and a beige metal box, and magically play perfectly reproduced music with it?
@@naamadossantossilva4736 Nobody over 40 can hear the difference anyway; and everyone under 40 listens to MP3s on their phones. And don't mention the people who talk about the "warmth" of "vinyls".
@@anonUK That's assuming you can map lower bit rates to a smaller frequency range. In practice you end up turning a lot of transients from smooth into square and saw waves, which distinctly create noise.
Up into the early 2000s, I remember using ADAT format in the recording studios. There’s still many master recordings stored on the format. ADAT had 8 tracks of digital audio and you could sync multiple recorders together. You had to use sVHS tapes too. Great video.
I used a pro-model one of these in the recording studio I worked for. Other than the XLR inputs and the specific 44.1kHz sampling frequency, it was very similar to the one you show here. It was so neat to see the digital audio on the TV. Not long later, we used DAT machines for this purpose, and they were much easier to use. The pro DAT machines allowed us to use 44.1kHz sampling. Consumer models only allowed 44Khz sampling.
Great video! These were used by a lot of musicians with home studios as a digital two track mix down mastering recorder. Way better quality than two track analog tape decks. You have to remember that this was the only relatively inexpensive way to record audio to digital for a few years. CD recorders were expensive and came later. As did DAT machines. We were mastering our music to audio mixdowns to HIFI VCRs which had great sounding audio, then these digital adapters came out. A few VCRs even had these adapters built in- like from Toshiba.
Another interesting thing you could do with this thing is quadraphonic audio. Of course, that’s nothing unusual, especially with reel to reel recorders, but you’d have the advantage of two channels being digital. The company that manufactured and maintained the animatronics in Showbiz Pizza restaurants in the 80’s used a machine like this to create the master for the show control tapes. They stored the show audio in the PCM data and stored the show control signals on the regular audio channels. They dubbed this onto regular quadraphonic reel to reel for the restaurants.
One thing I noticed is that the samples in the signal are staggered, i.e. if you look at the blocks, they don't form a horizontal line from left to right but a diagonal line. This has to be deliberate, since VHS wouldn't normally record that way. It also helps the error resilience.
I also had a sony PCM501 and a JVC PCM adapter too, even made some recordings onto a Sony EIAJ open reel video recorder just for the sake of it. This system was reliable, resilient and easy more hardy than damn 4mm DAT tapes and transports.
Yeah, DAT was a pain to interchange between decks. What finally killed it was not only lack of parts, but shoddy design. Nearly every Sony deck made eventually developed loose slant guides, the ones that set the angle that the tape takes as it wraps around the drum. You could feel how loose they were and good luck trying to get the angle right ever again if you tried gluing them in. The only deck i still have is the car stereo version, it can play anything. It uses what was referred to as "Non-tracking", basically roll tape and spin the drum, don;t even try to lock on to it, just read data as fast as possible and as many times as possible. Good, error free data is buffered and identified, then read out in the correct sequence at the correct rate. Works like a charm on tapes that won't play anywhere else. Only drawback it it's only analog out.
Re: your editor's note and not knowing why interleaving improves error correction: The answer is pretty simple, errors tend to occur in bursts, while error correction codes can only tolerate so many bit-flips per codeword before failing. If we didn't interleave the codewords, a modest burst can easily damage a codeword beyond the code's tolerance. But WITH interleaving, where we write out bit(0) of a bunch of codewords, then bit(1) of each, then bit(2), ..., those bursts of error go from damaging a few codewords by a lot, to damaging a lot of codewords only a little - keeping each one under the threshold to be repaired!
As a more concrete example, if one were to e.g. store 8 rows of data, followed by an xor of the data in them, data could be recovered after any burst error event that was confined to a single row, by replacing the missing row with the xor of all the surviving rows, but a small error that hit the end of one row and the start of the next could be unrecoverable. If one were to interleave the data 2:1, then the only way a single burst error event could damage anything would be if it was long enough to encompass the end of one row, the entire next row, and the start of the row after that. Using 4:1 interleave, a single burst error would need to encompass the end of one row, the next three entire rows, and the start of the row after that. Using this style of approach, one can get by with a rather small amount of error-correction overhead. Guarding against any single burst error per frame of up to seven lines long would require only eight lines per frame of overhead. Guarding against arbitrary combinations of up an up-to-seven line error and an up-to-six line error could be accomplished by putting at the top of each frame seven lines representing the xor of every seventh data line, and at the bottom of the frame eight lines representing the xor of every eighth data line,
thank you SO much for the warnings on flickering visuals - a lot of tech youtubers... well, youtubers in general, don't bother, and i have to try to look away really fast to avoid a seizure. it makes your content accessible to a wider audience & saves people's health
A peeve of mine is when they put a text disclaimer on the screen, but don't read it aloud. Nexpo is bad for that. Hey, what if the people who need that warning weren't looking at the screen right then? What if you started the video running while you were getting dinner finished and let the ads play, and so weren't looking at the screen when the disclaimer was there? Read safety alerts aloud AND write them to the screen please.
I remember most software (but especially games) In the early 80's, came on cassette tape here in the UK. Your Atari or Amiga, Spectrum etc would read the audio code from the tape cassette, which any tape recorder with a headphone out could be connected to the pc. The early (physical) copy protection measures which came with the software were pretty interesting.
I never cease to be amazed by the quality of your content and presentation. This is fascinating stuff. I am old enough for my first computer to have whopping 64 KB of memory, so the idea that a decade earlier there had been consumer tech capable of storing GIGABYTES is utterly mindblowing.
I was in TV broadcast business and we got our first still store unit in about 1982. It had physically huge Winchester drives that I think handled ONE GB. For backup it could spit out video as PCM data the same way as the Sony audio machine. It would be a screen full of block data patterns that was recorded on to 1 inch videotape (it worked on 3/4 in as well) It took a few seconds for each still to be sent or received.
You were doing well to have a digital still store in 1982 I reckon - in the UK several commercial television stations (not small operations either) were still operating programme playout utilising optical slides until 1989 when the ITV network finally mandated they upgrade...
In 1977, I was a sound engineer for the now defunct Radio Tees in Stockton on Tees, England. One of the "God Squad" (a religious group involved in broadcasting religious content) brought in a standard VCR (can't recall if it was Betamax or VHS)and PCM adaptor for recording of audio digitally. After playing with the setup for a while, I remember being astounded at the results that came off this thing.
Being 54, I remember when my father bought that vcr, top of the line for it's time, was the best way to record tv or LP records. Using the album cutter we could copy a worn record to a new album. Old tech by today's standard's but it did work well.
I worked in a mastering studio in the 90s and all production masters were produced onto Umatic video cassettes via modified umatic video recorders @44.1k 16bit. The tapes would also have room for a timecode track.
I used to use my HiFI VCR hooked to my Technics Amp/Tuner to record a five hour blues show on Saturday nights while I was out merry-making and listen on Sunday afternoons while I recovered.
I recently found a late '80s Sony EV-S800 Video 8 deck at a thrift store. It apparently contains a similar PCM adapter and is capable of recording multiple digital audio tracks in place of video on tape. From what I have read on it, the VCR was supposedly too similar in capability to Sony's DAT decks and was cannibalizing sales from them, so they didn't sell it for too long. It would be interesting if someone were to create a CED disc containing this type of video signal of a digital PCM audio signal. Then we could have digital audio on vinyl!
I was told by an old audiophile from the 70's-80s era, pcm adaptors were used by small department stores. They would use them to record hours of elevator music on Beta or VHS and play them during open hours. He said not national chains, but regional grocery and department stores. They would have a collections of seasonal tapes as well.
Sony was also working on a digital multitrack recording system in 1977, it had 24 tracks and a 16 bit 48 kHz sample rate and was recorded on metal particle tape, the prototype machine was used to record the soundtrack for "Star Trek, The Motion Picture" and sony got some very valuable information from the sessions and delayed the recorder until 1982 while requested features were added (the ability to "Scrub" audio and make a tape spice edit that did not introduce artifacts) The machine was sold as the PCM-3324 and used 1/2" tape running at 15 or 30 IPS.
Made extra interesting that the 2-disc reissue of that soundtrack was supposedly remixed from a backup analog multi to yield both the 2-disc and a 96/24 stereo file for commercial streaming or HDTracks download. So the aforementioned digital multitrack was either lost or the hardware is missing to play it back.
30 IPS only. Designed with expansion in mind, the tracks were actually narrower than the guard bands on the 24 track DASH machines. When the head design permitted it, the format was expanded to 48 tracks in the PCM-3348 using the same 1/2" tape. A 24 bit version, PCM-3348HR ran at 45 IPS. Early Sony tape stock was very error prone, such that later tape was actually manufactured by AMPEX and just labeled as Sony, so it does not surprise me that the first use of the format might have deteriorated beyond repair. Two track machines were made that ran at 7.5 IPS that used 8 tracks to interleave the data (PCM-3202). PCM-3402 ran at 15 IPS and utilised the same 8 track layout on tape, but the data was split between two tracks interleaved with one method and a 100% redundant pair with different interleaving. The idea was to allow razor splices, but there was a nice edit function in that one, but it required two decks connected together.
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About 25 years ago I was the chief engineer of a radio station in Australia. We used to do outside broadcasts live from nightclubs on weekends, and we had a deal with what was then the largest nightclub in the southern hemisphere in Melbourne, Australia. For the club's opening night, we were doing a special extended broadcast to help promote the nightclub. Usually we did outside broadcasts over ISDN lines (using essentially a hardware MP3 codec at 128kbps at both ends), but sometimes we used a radio transmitter if needed.
Since the club was new, their ISDN line was installed but hadn't been activated yet, and since this deal with the nightclub was worth money to the radio station a solution was needed, so we set up a temporary radio transmitter on the nightclub's roof... but as the club was huge, it was impossible to run cables throughout the club to reach the transmitter. Particularly, we needed to take audio from the DJ booth (which was high up above the dance floor), and before the club opened from a cafe at the front of the nightclub near the entrance. This would mean lots of cables all over the club which had to be tucked away and safe all night long, and for various reasons (mostly safety and the length of the cables) this was not an option.
The solution was actually to use two of these devices to encode audio to video, and decode it elsewhere in the club. We dismantled a security camera in the cafe, and under the DJ booth, and joined them together behind the security video recorder to essentially make a long video line, and used this to transmit audio from one side of the building to the other, in order to reach the transmitter.
(There were other problems to solve that night, such as the transmitter not being able to "see" our station building, so we had to bounce it via a receiver from a friendly TV station who then put it into an ISDN line for us, but that's another story).
We used to use these devices to record the on-air programme 24/7 (as required by law) onto VHS tapes in EP mode for 8-hour recordings while keeping the quality high, before we switched to digital recording to hard disk. It was the late-90's *shrug*.
I just wanted to mention it as it may be of interest. :)
I love the story. Thanks for sharing !
I assume this is the Metro Nightclub and EON FM 🙂
Back then 3RPP also simulcast the 21st Century Danceclub in Frankston on Saturday nights. They probably used a similar ISDN system?
I was slightly too young to go clubbing back then but enjoyed the simulcasts!
@@zoomosis here was me assuming it was Revs 😂
@@zoomosis QBH from Hitz FM. The place was a pub (Queen's Bridge Hotel) and underwent an insane renovation at the time.
And yeah most places were using musicam codecs over ISDN because it was just easy, and the high price of ISDN in Australia was still justified, but there were so many problems with Telstra's installations that I knew any new site was probably not working right even if the NT-1 showed signs of life. Broadcasting from locations like shopping malls always necessitated ISDN for the OB link back in the day.
@@benespectionwas going to guess QBH. Fascinating the sorts of things we had to do back in those days to make stuff like that work. I was in tech not broadcast but there was some overlap from time to time.
I always love the niche tech genre of "playing back a recording on a device that is not intended to play back that recording". Most of the time it's just graphical garbage, but here you've got an audio visualizer that wouldn't look out of place in Winamp.
Yeah I got some strong Geiss for Winamp visualizer vibes
In fact somebody could probably write a WinAmp visualizer using the same algorithm which could then be recorded on a standard VHS recorder which could potentially be played back by this one
@@peterjensen6844 A man of culture
@@unocualqu1era lol I legit used Geiss to mesmerize our baby once upon a time 🤣
@@peterjensen6844 it really whips the llama's ass.
Seeing how clean the raw signal of Alec's mic is during silence and knowing that's before any sort of audio cleanup makes me appreciate how well he's set up his studio for audio.
Right‽
The big blocks of white and black is likely the most significant big. The data is actually the 6 stripes of randomness. It doesn’t take much to make the wide strips stable white.
You see that at 1:46 ? Most of the bits of data is to the right of big white stripes.
@@LaughingMan171 Eyyy, interrobang user? :D
It's *so* much easier that way
Once again, glad to help. Just so everyone knows why I own one... It's because of the 8 hours of record time. It's usually married to a very cheap non-hifi VHS deck and it breathed new purpose into said machine and that's about it.
Why did you need 8 hours of vhs sound recording?
@@jesseestrada8914 because thats cool as fuck
@@jesseestrada8914 Because it's cheap. Reel to Reel is expensive, even cassettes are, but a 25 pack of VHS is dirt cheap and it's pretty comparable to the original signal. I'm the weird one that likes to just have music going in the background and just throwing a tape on, not needing to deal with Alexa or anything and just having tunes go.
I also appreciate the yes, I could have a Pentium III computer playing MP3s endlessly, but I want to this in a weird, fun way
What a very un-audiophile thing to say.
Just to add a few bits of info to the discussion, I worked as an engineer for a local NPR affiliate from the mid80's to 2005. We used the Nakamichi version of the Sony F1 the processor to record the Oregon Symphony for broadcast. One use of the 14 bit format was to allow for more error correction, which allowed for trial and error editing on a regular video tape edit machine. Recording the audio simultaniously to the linear audio channels allowed you to jog to the approximate location, then shifting a few frames one way or another allowed for crude edits with no buffer. The PCM processor was also used for the first live national digital music broadcast (Portland Baroque Orchestras Messiah hosted by Martin Goldsmith) utilizing a satellite uplink truck is Portland to send the encoded PCM video to NPR where it was decoded and fed to the network.
The first live national digital music broadcast having been done with video-encoded PCM is an amazing thing to learn! What year was that?
OPB! I must have listened to your work for as long as I can remember!
Heh, bits
I grew up enjoying your work, (at least NPR and PBS), thank you for everything.
Wow, that’s a valuable information! Was. That possible to synchronize several tapes or processors via something similar to wordclock?
I clicked on this video because it triggered a memory for me as well. In 1990, I was 13 and my parents were newly divorced. My mother's first boyfriend (he was only 24 to her 42) was as much of a tech freak as you and me. He's the one who taught me how to code and had me so far ahead of what was being taught in schools in Computer Science, that I felt it pointless to even choose that class.
Anyways, I remember that he had a large assortment of his favourite music, recorded on VHS tapes, and he would play them through the VCR and the connected home stereo receiver and speakers. So yeah, I saw somebody using this for digital audio playback in 1990 :)
Yep, used to do that in the early 90s. But as MP3s came out in the late 90s and of course CD-Rs took over.
_"I remember that he had a large assortment of his favourite music, recorded on VHS tapes, and he would play them through the VCR and the connected home stereo receiver and speakers."_
Did he actually use a PCM processor with a VCR or did he use a Hi-Fi stereo VCR?
@Watcher3223 that's exactly what I was thinking. It makes for some nice long tapes vs c30 c60 c90 and don't have to turn the tape around for the other side. And I remember VHS tapes being dirt cheap to buy. I remember Christmas around the late 80's early 90's we would be given cassette tapes and VHS tapes.
This is why Sony and Philips both initially only advertised the CD as being able to hold "one hour of music", not its official maximum capacity of 74 minutes -- because that's the longest length of U-Matic videotape that was available at the time.
Wait…whut?!??? MIND. BLOWN.
A techmoan & LGR reference in the video, and a VWestlife comment in the comments section?
Now *THIS* is quite the technology (enthusiast) connection!
Curiously, Sony and Ampex later released U-Matic cassettes with a thinner tape and longer length (Sony MDU-75 and Ampex/Quantegy DAU-83E respectively). At the same time, full-length 74-minute releases ceased to be a rarity.
That makes SO much sense
The alternative story is that the duration of a CD was set by the Sony President as it had to hold a full version of the Beethoven's Ninth Symphony without interruption
There was another use for these units. They would be used for high quality recordings of legal matters such as depositions, board meetings, etc. The long time runs and archival quality were very useful.
I was wondering about this. Such people would certainly be interested in the high fidelity, but not necessarily need a professional-level product, just a consumer level.
Alec missed the glaring best use case scenario for it in 2023. Uploading digital music to TH-cam to get around copyright strikes.
@@ewmegoolies 😂
@@dracodis I don't think the high fidelity would matter that much. However, being a digital recording, if the 0s and 1s turn into 0.7s and 0.3s from age, all you need to do is re-record it and your audio is safe for another couple of years or decades. If that happens to an analog recording you're f'ed
@@bene5431Ideally, you should run it through error correction each time making a copy, thus avoiding dropouts to accumulate over the copy generations . Using the smooth-out processing to fill in unrecovered holes is more dubious, because guesswork is guesswork .
Years ago a friend of mine just had to let me know that a local FM radio station that had been first to play CD’s was starting to play music from digital audio tapes.
My response was ‘so now we can listen to a little bit of disc and a little bit of dat!’ (insert rim shot here).
69TH LIKE :3
Rimjob shots?
🤣
Perfect. XD
Now there are 255 likes....
After Tom Scott's video, I was really expecting a video from you about how climate control in hell can be surprisingly affordable if you use a heatpump.
wait, what Tom Scott video?
@@gabridish On "The Technical Difficulties" video "Tom becomes the Mayor of Hell". He and Tom went to Hell, Michigan.
@@username65585 To clarify for anyone who hasn't watched that video, it's relevant because Tom mentions being driven there by Alec
@@a_commenter and Alec filmed it as well I think!
Tom also mentioned having to leave the vial of Hell dirt with Alec since he couldn't bring it into the UK. I was really hoping it would have made it to the prop wall and would have been an Easter Egg hidden in plain sight for a year.
Thanks for the video :)
Some notes:
03:17 - in context of this video, cheaper 14-bit PCM adapters were using only ONE chip - DAC. ADC conversion was made with the same DAC chip and some analog circuitry (successive approximation ADC).
10:10 - one line contains 6 x 14-bit audio samples, 2 x 14 bit error correction words and 16 bit checksum, 128 bits in total
13:50 - look for "STC-007" or AES 28-4 or US4459696 patent, that's STC-007 standard
15:28 - each next 14-bit word of the source is shifted 16 lines down, that's why patterns appear to be slightly diagonal
25:27 - yes, you can, any STC-007 adapter would read it
25:56 - because 14-bit is the standard (STC-007) and 16-bit mode is Sony's hack on it (starting from Sony PCM-F1)
26:12 - no, PCM-1 used its own, Sony-proprietary encoding format, 12-bit static resolution (14-bit dynamic resolution)
26:26 - VP-101 uses standard STC-007 encoding, compatible with 14-bit of Sony adapter (and not compatible with PCM-1)
26:39 - yes, SV-P100 is a STC-007 compatible recorder
26:53 - yes, that would work both ways
27:53 - exactly, 16-bit mode was a Sony's hack, re-purposing one error-correcting word for 15th and 16th bits
28:02 - indeed, 14-bit mode can withstand loosing 32 consecutive lines without an error, 16-bit mode can stand up to 16 lines only
31:13 - STC-007 PCM data also has more data than just audio, it contains 128 bit/line, that gives 128 x 490 lines x 30 fps / 8 bits = 235.2 KB/s, or 235.2 x 28800 s (T-160 SLP) = 6.77 GB
edit: fixed measurement unit
I remember from my time as a digital tape recorders technician that 16 bits ADCs were not very accurate (12 bits had +/- 1 bits accuracy while 14 and 16 bits were worst, leading to some "distorsion".)
That was not relevant for sound recording, as it offered better signal to noise ratio, but was when it was signals from sensors where accuracy was more important.
Wow, it's really great seeing people who know their stuff in the comments! I don't, to be clear, not on this topic, but I can see that if I wanted to make an even deeper dive, your notes would be a good starting point
Honestly, kudos just for using timestamps placed before what you're responding to so that jogging isn't necessary to in order to understand the note.
Your 6.77 GB calculation appears to be in base-10. Windows will show this as 6.459960938 gigabytes since data storage will be base-2.
I'm always amazed at the quality of the comments in this channel.
You didn't need a recording studio to need high quality recording. There are various live venues (churches, etc) that might want a recording. It's best to capture it at high quality so you had room to process it before dubbing it onto cassette, or maybe a custom run of records. For some it may have been a hobby. (Never underestimate the money people will spend on a hobby.)
I follow the same rule with modern digital media. Always get the highest possible quality version. You can transcode to a lower quality if needed but not a higher one, and every conversion between lossy formats reduces quality further.
Though, I had to tell myself it's a bit silly to store full-resolution PNGs from a flatbed scanner... Cropped JPEG is usually good enough there.
Is that why TimeLife Records had a run on seemingly high-quality recordings of e.g. new-age hymns, etc. in the 1980s & 1990s?
Yes, exactly. As a specific example, over a span of about 20-25 years or so, my dad used to make recordings of every performance of the chorale group he and my mom were members of. He started before these PCM adapters existed, never mind consumer VCRs, so he was using open-reel tape decks, and then duplicating the recordings onto cassettes for people who wanted a copy. But in an alternate history where he started doing this when these PCM adapters were available, I could easily see him having chosen this tech instead, for its suitability as an original source for repeated duplicates and higher source quality.
An added benefit would be that the archived material would probably degrade a lot less quickly than the analog option would. The analog tapes could wear out over time and without any error correction built in, the duplicated copies would get just a little worse with each copy. Not noticeable for dozens of iterations, but it probably could add up for larger volumes. I'd guess the digital audio made with this technology would hold up longer, and it would be easier to make perfect backup copies, which could be used to completely eliminate any problem of degradation over time.
I don't see it so much as a "consumer version" but a "consumer-compatible version", the kind of thing maybe a small campus radio station or in your example a church might make use of. Admittedly, I haven't tried to look up the historical price of a professional Betamax recorder vs. a consumer VHS VCR, but I'd expect the difference to be enough. I imagine it also would have been easier to run down to Sears to get a replacement if something broke, vs. dealing with vendor/distributor service, if the setup is made from "consumer-grade" hardware.
@@pshalleck I think you're describing "prosumer". True professional would have balanced line level stuff, but the prosumer would be happy enough with RCA jacks.
When I was in high school, I worked a part time retail job that used this system in store. It was used to play the store's music throughout the day thanks to the long play time.
Every week, head office would send a new tape with that week's mix and in store messaging.
Interestingly, that chain was a distant offshoot of Sony.
Thank you for tackling this system! I knew that using vhs for audio was done. Thanks to this episode, I now know how it was done.
This ^^ You could have hours of music on a single tape. It was great for parties if you just wanted to press play, rather than have someone manage a playlist of vinyls.
That's a really clever and weird way of doing BGM, I've seen plenty of Techmoan videos of such machines and their unique physical formats, sometimes just hacked up consumer stuff, but didn't imagine people using the method you describe.
This reminds me I've read about Video 8 also being used in that way for a heck lot of PCM audio runtime as well, likely about the same method.
I once was sat at the PC by my friend who had a birthday party - he asked me to manage the playlist that evening. It was one of the happiest evenings of my life, since his friends-musicians approached me here and there to ask for the name of the song. But it is different from changing the records all the time, I get it.
The throwaway line about piano being digital threw me for a loop. I'd never thought about it but player piano rolls are just punch cards which are digital data (as are music boxes). That realization is fun.
I assumed he meant because you play it with your digits. 😂
@@JoeUrbanYYC Genuinely - both
but what about the note velocities? it's not like those are encoded digitally on a note sheet
Note velocities are merely the quirks of the, ah, digital analog converter on the seat.
@@TechnologyConnections that's pretty cool
We used them for recording masters for a classical music label (orchestral, solo, chamber) They could then be transferred to tape and edited (digital editing was a little out of reach). Amazing sound quality and completely ‘professional’ quality!
Naxos? ^^
Fun fact: This was how I used to record at music festivals for a very long time. I would record onto the stereo hifi track as well as through a PCM. I still have my Sony F1 PCM and can still play back many of the archival tapes I have (though a huge portion of those have been digitized at this point).
Moved to a PC file format, actually. Because it's digital audio already, isn't it? I'm curious about the process, how do you copy the tapes onto a computer??
@@asnovasdodia There are PCM adapters which have S/PDIF connections (eg. Sony PCM-601). Otherwise you can also re-digitize the analog output once again. To be fair, that's still give going to give you excellent audio if done right.
I think iirc we used to put the SMPTE info on the analog to sync it to the midi controllers
Have you made your recordings available somewhere?
I always wanted the pcm module for my F1 system & never got it but I still have all the brochures for the F1 system I would have liked to have the rest of the F1 system as well I could only afford the VCR & camera
A work colleague recently told me that back in the late 90's when all night raves were broadcast over FM radio he used to digitally record them using his Akai VCR. He wanted to record the entire session without having to stay up swapping tapes so would set a timer and go to bed, then in the morning he could listen back to the entire 8 hour session.
I did the same to record an FM station program early in the morning. Program the VCR, record, then much later dub to compact cassettes.
If any of those tapes have survived, they would be absolutely awesome to hear today.
If those were recorded on a VCR that one might have at home, you were using the analog audio section of standard VHS tapes. Many of those had a compander circuit in them and at best would sound like a cassette tape with poor noise reduction.
@@jimmyklane thus, why the OP specified an AKAI brand VCR. They specialized in high quality audio equipment. They are actually most famous for reel-to-reel tape recorders. Why would you assume they used a "typical home" VCR anyways?
@@squirlmyYou’re correct, I did make an assumption however it wasn’t a completely uniformed one. I’m a musician, I’m familiar with (and an owner of several) AKAI Professional products. In the 80’s they made consumer products and VCRs were some of those products. I’m not aware of (although I’m not claiming a comprehensive knowledge base either) AKAI making any professional level VTR/VCR products and presumed a consumer product. Upon a second reading of the post I replied to he does say “digitally recorded” so maybe he remembers it being a professional level product and just didn’t specify. I don’t have a need to be right lol
A friend of mine had this. He used it to record his band live (long sets). But what was really cool (and you should have mentioned!), is that you can still record on the analog audio track of the VCR! So my friend would record the stereo board output to the PCM system and record a mic from the audience area onto the VCR’s analog audio track. I can’t remember if he had a stereo VCR or not at that point.
Great video as always!
Don't forget some late consumer VHS VCRs models had Hi-Fi audio option. The same audio was recorded on tracks at the edge of the tape and the same was recorded in Hi-Fi (on the same area as video data!). The Hi-Fi equipped VHS player read the better audio recording available on a tape.
@@lukask7445 gosh who could forget those terrible VCRs that would flicker between the two incessantly until “Hi-Fi” mode was turned off…
This brought up memories. My old piano teacher would use a Betamax and a PCM adapter to record concerts of traveling musicians. Or of student performances (many of his students went on to professional careers in classical music). I always thought it was so neat when he’d pull out a video tape and play back ridiculously high fidelity recordings of the piece he had just assigned me to learn over his giant Marantz horn speakers.
I suspect that those may have been Klipsch horn speakers, they may have also been Altec A7-500 speakers, I'm pretty certain that Marantz never made horn speakers.
I used one of these back in 1986 to record live classical concerts. Worked like a champ. It was how we had to do it. No more tape hiss though which then caused us to go searching for a solution to the next weak link in the chain. So that caused us to look at new microphone preamps and new mixing boards. It got expensive before it was all done. And it was great for live classical stuff where a stereo recording was fine. But modern and pop music wanted more tracks than just two. The race was on.
Okay, so you're an interesting one. How do you prefer to communicate on social media channels
Isn't that how Jack Renner started Telarc Records?
My step-father played in a band that played a wide variety of music on acoustic instruments. They played in a lot of cafes and small bars, and often when they began unloading their equipment that manager or owner would begin to look hesitant as if he thought their act might not be a good fit for his venue, and my stepfather would take a moment to explain to them that their quest for a sound system that would amplify their voices and instruments without introducing a lot of noise had unfortunately led to them buying a system that would let them play in stadiums. Do not be alarmed by the speaker towers taller than a human, or the mixing board mounted atop a rack of amplifiers the size of a dishwasher, it's all there to make sure that the mandolin comes through crystal clear.
You see a similar problem of live music vs your system in your home. Yes, both systems will comfortably play over 105db which is plenty loud. My home system has over 5kw worth of amplifiers even though they rarely go over a couple hundred watts. But they get to that couple hundred watts real damn fast so you get that live music thump. You also don’t get A the music fatigue of listening to loud music. Your peak levels are high. Your averages are lower. So you don’t get the ear fatigue.
Yep - I knew an organist who traveled around playing different instruments across the US and Europe, recording on a portable PCM + VTR back in the 80s. He'd take the tapes back, edit them down and publish on various classical labels. Just him and his gear - made for a low cost production.
Back in the day I used to store Amiga programs and data on a VHS tape recorder, using a SCART to RCA cable and an interface I built. Damned if I can remember much about it now.
It was tfe VBS. Video backup system. It was heavily used by swappers.
I remember i used one back in 94. And at that time it wasn’t new.
The best part was that the amiga stock config could outpu composite video w/o extra hw. We just needed a scart with a resistor ladder hooked up to the parallel port
The Amiga VBS couldn't handle as much data as the PCM or PC interface but it's just one cable and the software displayes the name of the stored data next to it - which means less data but you can *see* what you're looking for (on VCR).
Before I got my Amiga, I had an Amstrad CPC 464. There was a local radio station that - I kid you not - once a week sent software over the airwaves to be recorded onto cassette and then played back in the Amstrad's tape deck for loading 😂 It was magical. This was one advantage the Amstrad had over the C64 - copying cassettes was easy with two tape decks.
@@DanielSmedegaardBuus yep, that was totally something in the 80s. over-the-air software distribution, before it was considered cool
or a regular audio cassette tape ... like Atari, Texas Instruments, or Tandy (radioshack/realistic). You could also build one with a kit from Sinclair ... my first computer. I'd say Commodore too ... but that was after the shit show between them and Atari. Atari was an Amiga ... they had the rights first. What an interesting war they had lol. Mutually assured suicide.
Oh my god a Digital Equipment Corporation shirt!!! My dad worked there from basically the day I was born (in the late 80s) all the way up until its tragic demise in 1998. What a nostalgia bomb.
I was going to mention the shirt too and how much I want one!
That's basically the same for me but it was my mom. I still have an old Digital PC that we used growing up.
... but what is a MINI COMUPUTER ?
I recently obtained a Digital Equipment branded rolling computer workstation from a thrift store. It's built like a tank and is filled with VHS machines and audio gear for stupid audio fun. I had to have it.
@@swisspeach67 A fridge sized case with huge swappable cards for various features (cpu, cache, memory, drive controller). Mini because transistors fridge computer is small vs a room size tube computer.
That recording time seems key. Maybe this was intended as a prosumer device for recording concerts? There are countless venues which routinely generate hours of live audio, but don’t necessarily have the budget of a professional studio. Something like this might fill that niche. (Whether it was actually _adopted_ for that purpose is another question...)
*UPDATE:* I now see that the comments are flooded with people who used this device for _exactly_ that purpose. I choose to frame this as validation of my incredible powers of deduction!
I am impressed as much as I am envious...
Oh, It was.
I was wondering much the same thing. This seems like something the school system would have had back in the day for recording music festivals.
@@spugintrntlit would also be a decent item for small time pirates to get music and sell it undercutting any stores selling offical music, good enough to sell, not so outrageously expensive you'd never get a ROI
When myself and a bandmate took our master tape to Fantasy Records in 1988 to be mastered for our record, I was surprised when they gave us a VHS cassette back; it was the first I had heard of the technology...
How a guy can take a subject I (and maybe a whole bunch of others) have absolutely no interest in or recollection of and make it into an interesting learning experience and history lesson as as hold my attention for 30 mins is beyond me. Well done sir, I guess this is why I watch your channel, you're the cool nerd kid down the street. Cheers. Oh BTW nice T-shirt!
I was thinking the exact same thing. I love this guy.
My father was involved in the progressive rock scene in the late 1970s and early 1980s and he mentioned this type of devices being around in his circles back then. It did come in quite useful for the not quite professionals, but still ambitious hobby musicians in that era.
I'm amazed and constantly impressed at the amount of archaeology Alec has to do for these videos about commercial technologies within living memory.
In the early 80s, Mobile Fidelity Sound Labs actually sold pre-recorded albums on VHS and Beta that were designed to work with PCM adapters, making them some of the first commercially available digital recordings.
I have a Sansui PCM processor. I would love to find one of those tapes for my collection.
I actually have one of those releases: Donald Fagen's The Nightfly. Sounds amazing on my Sony PCM-601ESD!
The Boston public broadcasting system affiliate WGBH (VHF 2) would broadcast classical music on its WGBX UHF channel 22. The video portion of this classical music broadcast was *exactly* this black and white PCM video adaptor output. Presumably, you could feed the WGBX music broadcast back into a PCM decoder such as the one in this video, and hear the classical music in "almost CD quality".
Hey, two years ago, I found some information about Sony's 1970's PCM adaptor bit formats and error correction codes. I know which book it's in, I just need to dig it back up...
Imagine in 1975 you could just flick on your PMC insert an album casette and listen to some music in essentially perfect quality, at a time where radio was scratchy and vhs sounded like a tincan.
Sony really dropped the ball on this one. They had the hardware, they had the tech, all they needed was to iron out some kinks and get some studios to release their music in their format, it would have been a huge success.
This brought back some memories. At BBC radio, we used this to live transmit classical concerts from around the UK in the 80s. A PCM-F1 was used at each end of a standard TV circuit, expensive but worth it for a high value concert. This gave great stereo sound and as the classical network used no audio processing, the quality on FM was superb, albeit limited to 15k at the top end by FM. The system was also used to play back concerts off a Beta tape, although cueing it up and playing it in live was always somewhat scary! The PCM-F1 encoder and matching Beta machine were beautifully made and small enough for both units to fit side-by-side in a rack width.
I imagine that reserved satellite channels were occasionally used to distribute such transfers to a large audience across the world. I certainly was entertained to realize that most of the shows I watched were actually transfers intended for the stations to pick up. They'd always have cards where local advertising or announcements were supposed to go.
To think, I probably saw some of this audio back then and thought I was just looking at static!
My dad worked in a shop for twenty plus years and one of his coworkers had converted his collection of hundreds of records into over a dozen 8ish hour mix tapes on VHS tapes for the shop to listen to while working; they'd just have to pop a tape in in the morning and be good for most of the day. My dad always said the quality was amazing too and he couldn't believe it was coming from a VHS tape. Knowing that the guy who did that was a massive audiophile I'm now fully convinced he had a setup like this back then. Super cool!
It's probably more likely that he was simply using the regular analogue hi-fi VHS audio. That was good enough that it was widely used in British radio in the 80s and 90s for 24/7 radio station output logging; a few domestic VCRs using standard VHS tapes available anywhere were cheaper, more convenient and higher-quality than a couple of specially-modified open-reel audio recorders running slower than audio cassette speed (which was the previous standard way of doing it).
Just a few notes: Engineer Roger Nichols said some satellite TV companies had music channels, sending digital audio over video signal.
14-bit DID allow better error-correction. I remastered an album that had both a 14-bit and 16-bit version of the same mixes on the same tape for added safety.
I knew a guy who did live recordings with a HiFi VCR; using the analogue HiFi channels and a 501es to get another pair of tracks onto the tape.
Fun stuff!
11:38 Can we stop for a minute to appreciate that of all the CDs that Alec could have used for this scene he chose Enya's debut album?
I don't appreciate it.
@@thisguy2958 Bah! You probably like Brussel's sprouts, too. Dontcha?
Hey, it's a good album.
Also, a very non-offensive choice that isn't likely to rub anyone's feathers the wrong way.
Alec is a man of taste I see. Enya is legendary
and They Might Be Giants' Mink Car and Join Us!
I just spent some time acquiring a PCM device to retrieve recordings made in the mid 1980s. The tapes were made with a portable Betamax machine to record performances in Bali, Indonesia. It was essentially used as a portable recording studio. I have a friend in Vermont who recorded concerts the same way. These devices allowed many audiophiles to make field recordings of very high quality. The RCA inputs were just fine when connected to a portable mixer. I also know of a professional audio studio that used this format to back-up their digital recordings. BTW, the tapes were mostly flawless after nearly 40 years.
To your point, back in the 1970's, we were using what were essentially portable cassette recorders to record and store data (programs) but the need for random access to data was far greater than the need for large amounts of data so early floppy disks and hard drives were of far greater value than any medium that could store vast amounts of (then nonexistent) data.
I always enjoy your extremely well researched videos and trips down memory lane. Thank you.
Even our Commodore VIC-20 had an audio cassette deck for storage, though of course it was painfully slow. I believe it worked with the C-64 as well, though by then we had fancy 5.25" floppies.
A friend told me his family had a similar setup for their Sinclair, and that cassette deck had a tuning knob for drive speed. Apparently for one of his favorite swapped games, he had to make precisely timed speed adjustments to get it to load. 😀
Broadcast engineer here. The PCM on NTSC was fascinating. I could see you going down the rabbit hole of Nielsen audio encoding. There's free software [NACAT] that allows you to run against anything playing on your computer and it'll decide the ID numbers coming down the stream. It's fascinating as it's basically subliminal in a sense. That's about it though. I live in Indianapolis and have plenty of demo gear we could make work for something if you're interested
Years ago I was at a nightclub doing video recording of unnamed blues piano player and guitarist, there was also a guy there with one of these devices putting the audio onto a Betamax, he was recording both Digital and analogue. This was back in the 1990's and even though I had access to a Cable Access studio with a lot of high tech gear for the time I found this guy's setup nothing short of amazing. Thanks for the reminder, of that time I had a lot of fun shooting video in that club and got to meet some absolute blues legends.
The 8-hour recording ability has me thinking if one target market might have been non-audio-production commercial (ie, a whole working-day's worth background music for a shopping centre, assuming they even did that back then). That grey area between home users who don't need as much, and the pro users who need more.
I think that it could have been an alternative to reel-to-reel tape for home use. A recording time of 4 hours (at LP) would have been great for home use. A problem with using EP/SLP is that the video tracks overlap by a third on the right and left sides of the track, leaving only the middle third clear. With LP the tracks touch but don't overlap, and with SP there's a space between the tracks.
I just want to say... as a 22 year industry veteran, starting just after the dedicated engineers who studied on the job and had degrees and such, I learn a lot about my industry and my work on this channel.
I work with PCM audio daily, and only just now knew about it's history and details... thank you!
Yeah, I deal with PCM too, though I'm somewhat new compared to you in this industry (15 years working with audio). That was an interesting history lesson. It would be great if he talk about other devices like this in the future. ADAT is nice one, and it used S-VHS tapes.
Still using a 1980's Onkyo in my media center. My modern TV can still connect to this stereo without special adapters because both units have an optical port and the TV still supports PCM output sadly if you try to use any dolby encoding the stereo just buzzes loudly
Intellectual humility: something that's as exceedingly useful as it is rare to be found in engineers. Good on ya!
Calling piano music digital music is the biggest dad joke you've told on this channel. Well done!
Agreed -- I loved this one -- being 53, a keyboardist and a dog-dad.
I actually didn't get the joke until you called it a Dad joke. I thought he meant you could record piano music on paper tape and play it back again, like was pretty common in the 1800s 😅
Do I have to re-watch the entire video to find that!? 😂
Yeah, piano rolls were basically digital music, albeit with a very low bit speed.
But, he's talking about music on a piano, played with your fingers, or digits.
@@MeriaDuck around 11:30 mark
I think I've told this story before, but in 1978ish, I recorded the medium wave band on my VHS - all of it - as an analogue signal.
Next up, I took the undemultiplexed FM signal from half way through a tuner I was building, stuck that signal in the video in and recorded that too. Brilliant hiss free stereo when I fed that back in replay through a demultiplexer. Yes, I did it partly because I could, but also to record a 6 hour radio broadcast of a concert I was at.
How did I lock up the tracking you ask? Well, I took sync pulses from a Pong gam and fed them in to the right place on the VHS PBC.
Yes, it did go click click click - but not too disturbingly !
I understand that the video signal of vhs is about 6Mhz, but what device did you use to shift the medium wave band down to baseband? Did you make something yourself?
I love geeks. Wear it like a badge of honor. Those cliks where just pistol shrimp applauding.
Nope. The bandwidth was nowhere near 6Mz by the way. Broadcast TV was 5.625 MHz, a VHS cunningly squashed TV in to just over 1 MHz. I just stuck the wire in the hole.
@@JT-bb9di
@@JT-bb9di No need to shift it. The video bandwidth is just over 1Mhz, not 6, if it were 6 it could do the 5.625 MHz full broadcast composite colour signal, (I was a PAL BBC VT engineer). I just stuck a long bit of wire in to the video in on my piano key VHS. Same frequency - no shifting needed. I got lot of click though. I had to create a control track to make the heads find the tracks on replay. I used a 'Pong' game as a video sync source :-) I thought it up one night and got it working within about one and a half hours.
@@ejrupp9555 Oddly the clicks were quite acceptable ! Not loud at all.
I'm sure someone has mentioned this but these were big in the "Taper" community, and people used them to record Grateful Dead shows. I also believe I've seen reference to the F1 PCM unit being used for on set recording films since you could pair it with a luggable VCR.
Yes, the PCM F1 plus SL 2000 made a nice portable setup. Could even run on 12V or onboard batteries.
You get a thumbs up just because I’m headed to Dead and Company at Fenway in two weeks. 🏴☠️
"The sky above the port was the color of TV connected to a DAP visualizing the output of Alec's microphone."
Technology Connections, Techmoan and LGR: My holy trinity of retro tech on TH-cam. Love it.
Don't forget their friend The 8 Bit guy and all their friend Anders Enger Jenson that produces a lot of license free YT music. Its a good crowd.
You mean Techmoan, right?
@@denelson83 - yes. He mentioned Techmoan
@@KlodFather He misspelled it.
@@denelson83 - And since we all know what he meant... was it necessary to point that out? Really? OK. Thank you for not beating us with the ruler Sister Mary Denelson83 LOL. Transgressions in school used to be severe... You must be having flashbacks.
28:54 There were actually some pre-recorded PCM videotapes released by the audiophile label Mobile Fidelity Sound Lab back in 1983, on both Betamax and VHS, with the big album they released on the format, of course, being "The Dark Side of the Moon", as it seems like every new audio format needs to have DSOTM released on it (and for good reason). They also released other albums like "Crime of the Century" and "I Robot" on the format as well.
However, they haven't appeared to have released any other albums outside of the initial releases, and hell, while Discogs does have a category for the format (as "Digital Audio Cassette"), featuring a picture of an ad which listed their releases, the only one the category actually lists out is a Beta release of DSOTM, so you can assume that the line didn't last too long (this was the same year the CD launched in North America and Europe) and the tapes themselves are incredibly rare (according to the Discogs listing for DSOTM, only around 100 of each release were produced).
A Betamax copy of the Dark Side Of The Moon. I want one now because that is funny.
@@daemonspudguy To be honest I'd rather have the quad reel to reel version.
This should be implemented as an input and output format in ffmpeg. I would love that. :D (Edit: on a more serious note, a good video capture of such a source tape would be much easier for most of us to do than to get hold of a pcm-adapter.)
Excellent end of term project for a heterogeneous parallel programming class (often NVIDIA CUDA) or a GPU hackathon. For big bonus points, transcribe from a 4k video stream taken by a handheld cell phone pointed at a video monitor playing the stream from tape.
Sounds more like a project for VHS-Decode to tackle
There is a software project called SDVPCMdecoder for decoding video files back into audio. I don't know if there's something that would work in reverse, but... maybe.
There is already software to do this, but the capture needs to include lines at the very top which most capture devices miss out. So it's not as simple as it seems.
When the Bose wave "boombox" came out, they had a show at the local store. Since the whole demo was about sound quality, the demo was played back on a PCM machine. They also used a large number of slide projectors instead of movie film for the visual. Quite the show.
I think one reason home computers didn't really see this type of videotape storage is the almost impossibility of accessing random data if it's not close to where the tape head currently is with the system.
It's okay for large backups, movies, and continuous audio... but anything else quickly becomes a nightmare. You'd want to store these gigabytes of content somewhere else so you can use them, and that was still a difficult problem like you've mentioned!
LGR once covered a videotape backup system for a computer.
When I was a kid my dad's used caset storage to run the backups for his job cassettes are great for cold storage
Tape cassette-based backups to back up your whole hard drive was not uncommon back in the Windows 3.1-ish days. I suspect the tapes were higher quality than your standard VHS though, and it was around when hard drives were in the realm of hundreds of megabytes.
Yes that's true. Without a control system for the deck, something that wasn't standardized on consumer VCRs, it is not practical for random access.
Back in the 90's I remember there was the Video Backup System for the Commodore Amiga made by Lyppens Software Productions, a neat product intended for making hard disk backups to VCR. I don't think it sold very well and was basically killed off by Iomega's Zip Drive.
One reason digital tape was not very popular with microcomputers of the day was that it was very difficult to deliver (and to process) the sustained stream of data (at about 1.5 megabits/s) in the microcomputers of the time.
When using a card and a VHS recorder, you would really need to keep up with the speed.
When using DAT tape (recorders were available for computers, these were in the half-height 5.25" form factor and lacked the audio part), a common problem would be that the data was not provided quickly enough, and the drive would stop, rewind, play until the end of the recorded data and then go back into record mode to write data until again its buffer would become empty and it had to stop again.
That constant back-and-forth shuttelling was bad for the mechanism and the tape, and it dramatically increased the time to record the entire tape.
This problem in fact still exists today. Over time, capacity of backup tapes has increased a lot, and as the time to record the entire tape has remained about the same, that means the datarate went up. On a modern LTO-9 tape with capacity of 18TB, the datarate is 1000MB/s. That still is difficult to sustain over an entire backup run.
As a follow-up to this, you've *got* to take on the oddity that was D-VHS: digital audio (even Dolby Digital or DTS tracks) _and_ digital video (up to 1080i!), all on a video tape! Truly a versatile piece of consumer physical media, provided you had the codecs to support reading or writing to the tape. It could even be an interesting segue into the early DVR days of television - PCI cards, MPEG-2 codecs, Firewire ports on cable boxes, W-VHS for Japanese MUSE television, you name it. A little less unique than recording digital PCM audio into a composite analog video signal, but you've spent so much time on the various quirks and features of VHS and Beta both that a video (or series) covering the later years of the format would be welcome content.
It's mind blowing to see the capacity: up to 50 GB.
Yes, a dual layer BD. On VHS tape (I think it uses S-VHS formulation or was it a tiny bit better?).
After seeing how densely the data had to be packed onto tapes just for this, I wonder if D-VHS required finer-grain tapes than standard VHS, and the only real similarity was the shape of the cassettes (and the players being backward compatible).
@@stevethepocket From memory, S-VHS metal particle tape (so finer grain) and of course, we're talking about stuffing extra reliable digital data into possibly terrible quality 240 line video signals here, vs. D-VHS that doesn't need to deal with any of that NTSC crap after all, this whole deal is quite similar to dial-up, having to piggyback on the limitations of a medium and use it in incredibly ingenious ways, D-VHS tho doesn't need to care about the piggyback stuff, being way closer to the jump from Video 8 then Hi 8 and finally Digital 8.
Digital 8 uses the same tape as Hi 8 to store quite a few gigabytes as well.
@@Kalvinjj Now I'm wondering if purpose-built data tape drives used heads on a tilted drum too or if they had other ways of maximizing bandwidth.
@@stevethepocket That's interesting indeed, and several different variations exist. I do know that helical scan systems like VHS, Beta and all the common video tapes are common, but so is LTO nowadays, which just as the name suggests, is linear instead, with several tracks parallel on the tape. Now, what they physically do to have tapes up to several terabytes, no idea.
I remember the days when nearly every recording studio control room had at least one Sony 5800-series 3/4" video tape deck in the rack...and remember that there was (nearly) no limit to the number of dollars a well-heeled audiophile would spend for the perfect audio recording/ playback. The Japanese electronics industry has a record of answering the question nobody was actually asking. This is a curiosity, and and rather prophetic how it merged the computer data world with that of audio purists.
I still remember the first time I disassembled a VCR player. At that time I was about 14 or 15, but I already had enough knowledge to be able to disassemble and reassemble it without damaging anything, and I remember it blew my mind. The mechanism, so beautiful! I remember inserting and removing the tape several times just to watch the mechanism pull and return the tape into the cassette. Actually, I was able to improve the audio quality. Since new, I noticed the audio was a little weird compared to other VCR players I knew. When reassembling mine, I found out that the audio head came misaligned from factory. This player lasted for several years at home before being replaced for a DVD player. Nice memories!
I was lucky enough to be given a "broken" VCR to take apart. Not only did I learn about the fascinating mechanisms, I discovered that it actually worked just fine!
Dude, as usual your writing is excellent. You setting this up, giving the history, and then showing the implementation is perfect. 👍
29:56 the lack of random access was the issue. Same reason why tape disks today aren't consumer devices. Most data you don't access sequentially, only video and audio.
Alec, Another great video.
A couple of notes about Sony consumer PCM adapters. The Sony PCM-F1 adapter was released in 1982 along with the SL-2000 portable Betamax recorder. Both could take an NP-1 battery pack and allow portable digital audio recording, the F1 also included microphone inputs, and semipro recordists often hung that pair off the end of a Tascam or Yamaha mixer and made digital recordings of events.
They were also used by record companies to make copies of master tapes for distribution to artists and label execs.
I was looking for a comment like this. I am wondering if most of these were used a a semi-professional context like sending preview tapes around to people who did not have any other reason to have the professional equipment.
For some reason I love using digital data in ways it is not intended to be used. Like opening a sound file as an image file.
I assume that you like spectrograms as well? Hidden images in music.
No one seems to appreciate the linux 'cat xyzzy.jpg > /dev/audio' thing as much as I do. ...and while it's true that I've never done that (it sounds bad and you can bork your speakers), I love that you *can* do that.
Here's a fun thing you can do with digital data. Databending!
If you convert a picture, any picture, into a .bmp, then open it as a raw binary file in Audacity, you can then add sound effects like reverb, echo, phasers, whatever you want to the "audio", then export it as a .bmp again. As long as you don't mess with the header at the beginning, you can create some really neat distortion effects.
Back when I participated in the Java 4K Game Programming Contest, someone got the bright idea that "hey, couldn't these be shown as images?" So I wrote a program that turned any 4K or smaller game into a PNG file. Initially in black and white, later color. Then I made a launcher that could read the images directly and launch the program. Before you knew it, all the games were encoded as images which were being passed around for fun.
And that is what happens when you get too many geeks together in one place... 😂
@@redpheonix1000 I wonder what the opposite would do-converting audio to graphics, messing with Photoshop filters, and converting back.
The piece de resistance of Sony's line was their famous Sony PCM 601 ESD, which had a SPDIF (Sony/Philips digital interface) so you could copy the digital stream to non-videotapes.
Music Producers used these a lot in the early '80s, to preserve audio fidelity with multiple copies/versions of mixes and recordings. Popular with remixers
That sounds like a more professional use case than the consumer model was designed for?
My mom worked for Digital Equipment Corporation for most of my childhood so seeing that shirt brought a smile to my face! As a consequence of her working there, I remember seeing a VT100 hanging around at her office. As an IT person now myself, it's cool to me that we still use VT52 or VT100 emulation for terminal software. I think I still have my first computer which was a Digital PC. Thanks for the inadvertent trip down memory lane!
My mom and aunt did too!
I really love watching your videos, as someone whose done Sound Design, Video editing, music composing, and everything in between, I appreciate the rich history that audio and video have! Also, I watch your videos at a faster playback speed, but still fully understand all the information, so I don't mind the longer videos! Please keep making great content and rich history videos! :D
These were used sometime in the 80's by BBC Radio for some onsite OB recordings, usually classical music. IIRC they replaced digital reel to reel recordings (made on, I think, Mitsubishi?) that had to be replayed in the OB truck in the studio centre carpark. Recordings were made on Beta and replayed on a C9/701 unit that lived on a trolley that was wheeled into the appropriate control cubicle. I've also got a vague memory of them being used for live OBs that had a video link out of the venue.
I'm glad you posted that story, because I remember being a new engineer in BBC News' Spur Central Apparatus Room (SCAR) around 1983 and seeing that unfamiliar signal coming through our switching centre and being told it was a Sony F1. I only vaguely remember that it was an OB from somewhere!
What do you mean by "OB"?
@@mattgies Outside Broadcast. Nowadays a quality audio recorder can fit in a pocket, but then they were big and heavy, Google "Mitsubishi X-80 or Studer A80". It was permanently mounted in an OB van. When a concert was recorded for later broadcast the mixing desk might be set up in the venue and it's record output tielined out to the recorder in the van. Network Radio didn't have an X80 so the broadcast would be repro'd by the van/truck in the carpark and tielined to the network continuity suite (master studio). Once concerts started being recorded on Beta it was easier and cheaper to keep a dedicated repro machine at base.
You should do an episode on trash compactors. Where did they go? I grew up with one. It was amazing. Actually, I hated it when I was young because I had to take out the heavy garbage. But I know I would love it as an adult. I feel like a lot of younger people don't even know we use to have them.
They were banned after trying to kill Luke and Leia.
We have one of these Sony devices to record up to 15 analog data (DC-5kHz) channels via a multiplexer. It is from the USA so requires an NTSC video recorder and 240-110V power supply converter. And there are two audio channels too. Works a treat. Replaced an earlier Australian-made 4 channel unit using FM modulation onto a 4 channel reel-to-reel, which dated back to the late '60s.
If DankPods and Technology Connection do a collab nerding out on obscure audio tech my world would implode
That's really cringe dude
Same tbh
TC: turns something on
DP: STAND BACK HE' ARMING THE NUGGET!
A car-themed collab would also be interesting to see
Don't think they're quite on the same level dude
Minor point about CRC - CRC is error detection, not correction. You need some type of ECC, like a Hamming code, for that. Reed-Solomon is a newer one (but not that new - it's used on CDs), but probably too complicated and too late for a device like this.
I worked for Sony's short-lived Pro Audio division back in the 1980's. We developed a DASH system (Digital Audio Stationary Head) that used a 24-track audio deck to lay down digital audio in stereo. This would be used for mastering an audio mix in a professional recording studio. It used Reed-Solomon coding to take care of error correction.
@@geoffhetzel9691 Yeah, Reed - Solomon was invented in the 60's, so it makes perfect sense stuff from the 80's would use it, including CDs (the first CDs were introduced to the market in 1982, so most of the key product development was probably late 70's). But, as was mentioned in the video, some of these PCM devices date to the 60's and appear to be compatible with the newer ones. Theoretically, they could have use Reed-Solomon since I think it did predate the earliest units he mentioned, but it would be a tight fit. Hamming code is alot simpler and was invented in the 40's, so it's probably a better candidate, given the electronics of the day and product development schedules. It's also possible both were used. Perhaps the earlier 14 bit ones were Hamming and the later 16 bit ones were Reed-Solomon. That would actually make alot of sense - new products, like CDs or your DASH system, are rarely truly new inventions, but instead incorporate lots of earlier work.
Like you say, Reed-Solomon encoding is very widely used. Apparently we haven't found anything massively better because it's still getting incorporated into standards like DSL, ATSC, DVB, Blu-Ray, and many others. It was even used on the Voyager probes.
That was very interesting. When I had a job as a teenager from 1995 to 1997 as a rapper and clean up boy in a meat department of a grocery store, I did have some cutting duties but it was the wrapping machine that fascinated me. It was likely from the area you are describing and it used an audio cassette to digitally feed each week's prices for each product into the machine so that when we enter the product code it priced it properly. I remember observing my boss programming and audio cassette in the office where they had the device to put in price data and converted to an analog cassette tape and then loaded on the machine in the Meatpacking room. Quite fascinating and I never fully understood how it works but now I do. I've been a lurker up until now but I really appreciate your content!
Sony modified the 14bit standard to add the extra 2bits . The PCM 1 was a 12bit converter with a 2 bit level shifter. (This was my thing in the 80s)
What a coincidence, I just found a bunch of recordings (almost 28 hours!) someone posted on TH-cam from Live 105 KITS from 1989-1990 that was recorded using PCM to a VCR. There wasn't much info that I could find about "PCM adaptors" on YT (or I wasn't looking hard enough), and about a week later here you are with a video on the exact subject I wanted to know more about. Awesome!
Love the visual aid of the screen on your desk displaying your mic input. Your productions are always as enjoyable as the text of your videos themselves.
This reminded me of my habit to record LOOOOONG (6hr+ nighttime) radio shows to VHS in LP mode, because the audio was far better than anything we had back then.
I remember a friend in a band during the early 90s had one of these he got in 1989. Was amazing quality. I remember playing one of the VHS tapes out of curiosity and seeing the block pattern like you showed. He also called it a PCM ... I just called it an ADC-DAC.
I didn't realize these were around much earlier than 1990. These were NOT cheap either. $2k in 1990 was a lot of money (over $4k today)!
$4K is a lot of money to a consumer, but a small commercial recording studio could probably spring for that.
8:47 _"That might look like a bunch of black and white dots to your eyes, but to the right circuit, that looks like bits"_
- I'm reminded of PaperBack by Oleh Yuschuk (of OllyDbg) that let's you back up files to paper by printing them out as small binary squares, then you can recover them by scanning the paper backup and running it back through the program (essentially giant QR codes before QR codes became ubiquitous after smartphones became a thing).
The "shuffling the data around" approach is used in deep space (and presumably less deep space) communication encoding too. The idea being they characterise the sorts of 'damage' that normally occurs to a signal and find it is often time-limited. So, you shuffle the signal and spread the 'damage' such that each error correcting section gets fewer bad bits, and the maths (Hamming codes) can recover the bad bits per section. You then un-shuffle, and hey presto, the original data. Compare to it being perhaps easier to fix five small holes in your tires than one giant hole.
And if I recall correctly, the CD and DVD formats (for both audio/video and data) do the same thing for the same reason.
We used 'Digital tape recorders' (Multi-track) in 1989-1993 in a few pro studios I used to work at back in the day. We produced a few famous albums back then. Thanks for showing this idea to today's inhabitants. Stay adaptive and creative, folks. Every age has problems that need simple, cost-effective solutions. "Water seeks its own level / Lightning always takes the easiest path" (Development/Marketing/Consumer truths)
You should do a video on samplers from the 80s to 90s. Love that this is something that can be done with a VCR. It's insane. Could even be a capture card potentially?
There actually were official pre-recorded releases on this format, believe it or not. Mobile Fidelity Sound Lab (MFSL or MoFi) made a few back in the early 1980s for the audiophile consumer market (on both VHS tape and Betamax tape, depending on what the customer wanted). One of the albums they released on this format was Pink Floyd's Dark Side Of The Moon, which is probably the rarest official release of Dark Side Of The Moon ever released (I would say "most sought after" but truth is I dont think most collectors even know it exists, because most collectors focus on vinyl only still). MFSL didnt mass produce these of course; they were made by hand whenever someone ordered one, and probably less than 100 copies were made of Dark Side (and who knows how many of those have been tossed in the garbage in the years since by someone cleaning out the estate of a dead relative and just discarding it as "some old vhs tape").
This was in 1983, so may well be the first digital release of this iconic album; the first CD release of it was also in 1983 (in June), in Japan, but Im not entirely sure of the timeline on which of the two came first. Would in any case be very interesting to compare the two, both in terms of just sound quality, but also comparing the masterings.
Funny to think DSOTM was only 10 years old at this point. The original analogue masters would've still been in pretty good condition.
@@zoomosis I often muse about how much changed in 10 years in the last century, in terms of how things age technically; whereas in this century we have still have breakneck technological change, but the style and technical depth of music hasn't really changed much in the last 20 years at all.
Can you imagine people's faces, when you show up at an audiophile meeting with a crusty old BetaMax recorder and a beige metal box, and magically play perfectly reproduced music with it?
That's ridiculous. Audiophiles don't have friends.
@@EriksGarbage
Other audiophiles?
@@anonUK Are fools and always wrong.
@@naamadossantossilva4736
Nobody over 40 can hear the difference anyway; and everyone under 40 listens to MP3s on their phones. And don't mention the people who talk about the "warmth" of "vinyls".
@@anonUK That's assuming you can map lower bit rates to a smaller frequency range. In practice you end up turning a lot of transients from smooth into square and saw waves, which distinctly create noise.
Up into the early 2000s, I remember using ADAT format in the recording studios. There’s still many master recordings stored on the format. ADAT had 8 tracks of digital audio and you could sync multiple recorders together. You had to use sVHS tapes too. Great video.
I used a pro-model one of these in the recording studio I worked for. Other than the XLR inputs and the specific 44.1kHz sampling frequency, it was very similar to the one you show here. It was so neat to see the digital audio on the TV. Not long later, we used DAT machines for this purpose, and they were much easier to use. The pro DAT machines allowed us to use 44.1kHz sampling. Consumer models only allowed 44Khz sampling.
The first consumer DAT machines used 48kHz. Later ones also could do 44.1.
Great video! These were used by a lot of musicians with home studios as a digital two track mix down mastering recorder. Way better quality than two track analog tape decks. You have to remember that this was the only relatively inexpensive way to record audio to digital for a few years. CD recorders were expensive and came later. As did DAT machines. We were mastering our music to audio mixdowns to HIFI VCRs which had great sounding audio, then these digital adapters came out. A few VCRs even had these adapters built in- like from Toshiba.
I actually recorded some bands live back in the day, using a hi-fi Betamax machine. The playback blew the musicians' minds. Good times!
Another interesting thing you could do with this thing is quadraphonic audio. Of course, that’s nothing unusual, especially with reel to reel recorders, but you’d have the advantage of two channels being digital. The company that manufactured and maintained the animatronics in Showbiz Pizza restaurants in the 80’s used a machine like this to create the master for the show control tapes. They stored the show audio in the PCM data and stored the show control signals on the regular audio channels. They dubbed this onto regular quadraphonic reel to reel for the restaurants.
One thing I noticed is that the samples in the signal are staggered, i.e. if you look at the blocks, they don't form a horizontal line from left to right but a diagonal line. This has to be deliberate, since VHS wouldn't normally record that way. It also helps the error resilience.
You, sir, are a bigger nerd than me, and I am here for it. don't change a thing, keep giving us the deep dives we didn't know we wanted!
I also had a sony PCM501 and a JVC PCM adapter too, even made some recordings onto a Sony EIAJ open reel video recorder just for the sake of it. This system was reliable, resilient and easy more hardy than damn 4mm DAT tapes and transports.
Yeah, DAT was a pain to interchange between decks. What finally killed it was not only lack of parts, but shoddy design. Nearly every Sony deck made eventually developed loose slant guides, the ones that set the angle that the tape takes as it wraps around the drum. You could feel how loose they were and good luck trying to get the angle right ever again if you tried gluing them in.
The only deck i still have is the car stereo version, it can play anything. It uses what was referred to as "Non-tracking", basically roll tape and spin the drum, don;t even try to lock on to it, just read data as fast as possible and as many times as possible. Good, error free data is buffered and identified, then read out in the correct sequence at the correct rate. Works like a charm on tapes that won't play anywhere else. Only drawback it it's only analog out.
Re: your editor's note and not knowing why interleaving improves error correction:
The answer is pretty simple, errors tend to occur in bursts, while error correction codes can only tolerate so many bit-flips per codeword before failing. If we didn't interleave the codewords, a modest burst can easily damage a codeword beyond the code's tolerance. But WITH interleaving, where we write out bit(0) of a bunch of codewords, then bit(1) of each, then bit(2), ..., those bursts of error go from damaging a few codewords by a lot, to damaging a lot of codewords only a little - keeping each one under the threshold to be repaired!
As a more concrete example, if one were to e.g. store 8 rows of data, followed by an xor of the data in them, data could be recovered after any burst error event that was confined to a single row, by replacing the missing row with the xor of all the surviving rows, but a small error that hit the end of one row and the start of the next could be unrecoverable. If one were to interleave the data 2:1, then the only way a single burst error event could damage anything would be if it was long enough to encompass the end of one row, the entire next row, and the start of the row after that. Using 4:1 interleave, a single burst error would need to encompass the end of one row, the next three entire rows, and the start of the row after that. Using this style of approach, one can get by with a rather small amount of error-correction overhead. Guarding against any single burst error per frame of up to seven lines long would require only eight lines per frame of overhead. Guarding against arbitrary combinations of up an up-to-seven line error and an up-to-six line error could be accomplished by putting at the top of each frame seven lines representing the xor of every seventh data line, and at the bottom of the frame eight lines representing the xor of every eighth data line,
thank you SO much for the warnings on flickering visuals - a lot of tech youtubers... well, youtubers in general, don't bother, and i have to try to look away really fast to avoid a seizure. it makes your content accessible to a wider audience & saves people's health
^ ditto :>
A peeve of mine is when they put a text disclaimer on the screen, but don't read it aloud. Nexpo is bad for that. Hey, what if the people who need that warning weren't looking at the screen right then? What if you started the video running while you were getting dinner finished and let the ads play, and so weren't looking at the screen when the disclaimer was there? Read safety alerts aloud AND write them to the screen please.
I remember most software (but especially games) In the early 80's, came on cassette tape here in the UK. Your Atari or Amiga, Spectrum etc would read the audio code from the tape cassette, which any tape recorder with a headphone out could be connected to the pc. The early (physical) copy protection measures which came with the software were pretty interesting.
You must be sad that today's game only comes via download.
I never cease to be amazed by the quality of your content and presentation. This is fascinating stuff. I am old enough for my first computer to have whopping 64 KB of memory, so the idea that a decade earlier there had been consumer tech capable of storing GIGABYTES is utterly mindblowing.
Mine was a Commodore VIC-20, with a huge 5k (2k ROM, 3k RAM).
I was in TV broadcast business and we got our first still store unit in about 1982. It had physically huge Winchester drives that I think handled ONE GB. For backup it could spit out video as PCM data the same way as the Sony audio machine. It would be a screen full of block data patterns that was recorded on to 1 inch videotape (it worked on 3/4 in as well) It took a few seconds for each still to be sent or received.
You were doing well to have a digital still store in 1982 I reckon - in the UK several commercial television stations (not small operations either) were still operating programme playout utilising optical slides until 1989 when the ITV network finally mandated they upgrade...
In 1977, I was a sound engineer for the now defunct Radio Tees in Stockton on Tees, England. One of the "God Squad" (a religious group involved in broadcasting religious content) brought in a standard VCR (can't recall if it was Betamax or VHS)and PCM adaptor for recording of audio digitally. After playing with the setup for a while, I remember being astounded at the results that came off this thing.
_"The littlest blip could flip a bit!"_ Oh how I love your writing Alec !
I saw that sneaky little interrobang hidden in the captions at 17:58. Nice little bit of grammatical nerd-dom.
I need someone wiser than me to turn that distorted audio at about 23:15 into an internet shitpost lmao
Being 54, I remember when my father bought that vcr, top of the line for it's time, was the best way to record tv or LP records. Using the album cutter we could copy a worn record to a new album. Old tech by today's standard's but it did work well.
I worked in a mastering studio in the 90s and all production masters were produced onto Umatic video cassettes via modified umatic video recorders @44.1k 16bit. The tapes would also have room for a timecode track.
I used to use my HiFI VCR hooked to my Technics Amp/Tuner to record a five hour blues show on Saturday nights while I was out merry-making and listen on Sunday afternoons while I recovered.
recovered from what?
@@JPX64Channel The previous evenings' merry making
I recently found a late '80s Sony EV-S800 Video 8 deck at a thrift store. It apparently contains a similar PCM adapter and is capable of recording multiple digital audio tracks in place of video on tape. From what I have read on it, the VCR was supposedly too similar in capability to Sony's DAT decks and was cannibalizing sales from them, so they didn't sell it for too long.
It would be interesting if someone were to create a CED disc containing this type of video signal of a digital PCM audio signal. Then we could have digital audio on vinyl!
"Looking at the snow of a tv tuned to a dead channel"
Hot damn, that's a good Neuromancer reference. Just, really neat
I had to scroll through forever just to see this comment.
I was told by an old audiophile from the 70's-80s era, pcm adaptors were used by small department stores. They would use them to record hours of elevator music on Beta or VHS and play them during open hours. He said not national chains, but regional grocery and department stores. They would have a collections of seasonal tapes as well.
Sony was also working on a digital multitrack recording system in 1977, it had 24 tracks and a 16 bit 48 kHz sample rate and was recorded on metal particle tape, the prototype machine was used to record the soundtrack for "Star Trek, The Motion Picture" and sony got some very valuable information from the sessions and delayed the recorder until 1982 while requested features were added (the ability to "Scrub" audio and make a tape spice edit that did not introduce artifacts) The machine was sold as the PCM-3324 and used 1/2" tape running at 15 or 30 IPS.
Made extra interesting that the 2-disc reissue of that soundtrack was supposedly remixed from a backup analog multi to yield both the 2-disc and a 96/24 stereo file for commercial streaming or HDTracks download. So the aforementioned digital multitrack was either lost or the hardware is missing to play it back.
30 IPS only. Designed with expansion in mind, the tracks were actually narrower than the guard bands on the 24 track DASH machines. When the head design permitted it, the format was expanded to 48 tracks in the PCM-3348 using the same 1/2" tape. A 24 bit version, PCM-3348HR ran at 45 IPS. Early Sony tape stock was very error prone, such that later tape was actually manufactured by AMPEX and just labeled as Sony, so it does not surprise me that the first use of the format might have deteriorated beyond repair.
Two track machines were made that ran at 7.5 IPS that used 8 tracks to interleave the data (PCM-3202). PCM-3402 ran at 15 IPS and utilised the same 8 track layout on tape, but the data was split between two tracks interleaved with one method and a 100% redundant pair with different interleaving. The idea was to allow razor splices, but there was a nice edit function in that one, but it required two decks connected together.