I figured it out a few years in to my adulthood and experimentation with radio receivers (building them and such) that they were referring to "beat frequency". But, when I was 10, I was just as perplexed as to what is this "beat" switch for as switching it on or off did nothing.
Before the internet you just had to ask around. Any book at the public library which might have helped was already stolen and that was that. Nowadays no one on You Tube even knows what a library is any more.
I have been tinkering with radios and recording since I was a kid and those devices were new, have a full amateur radio license and have a degree in high frequency electronic engineering AND I NEVER KNEW UNTIL TODAY WHERE THAT SWITCH WAS FOR! Thank you for explaining this unusual but very useful feature. 😅
I think it’s interesting that over the years they didn’t come out with a marketing term that would explain its function better for people who had no idea. Something like “Radio Noise Reduction” akin to Dolby.
@@GaryKeepItSimple And the technically correct term for what Dolby Noise Reduction does is compansion, but they sure as hell didn't market it as a compander to the general public.
Why would they. It's like "2000W PMPO" found on boom boxes in the late '90's, early 2000's. No one actually knew what that meant, either - except maybe for people like me. Another fictitious marketing measurement of perceived output power. It's interesting that they can get 2000 watts from an amplifier that was running on 12V maximum producing under 3 watts.
MPX is FM stereo. It works with a nearly inaudible 19kHz carrier tone which could beat with the recorder's bias oscillator. The MPX filter removes this high frequency so this doesn't happen.
MPX is short for "multiplex". An FM signal can have up to 6 signals mixed together - L+R, 19kHz pilot, L-R, 57kHz RDS (scrolling text) plus 2 hidden subcarriers at 67kHz & 92kHz. I've never seen an MPX filter button but it would work on the same principle. I have seen MPX line-out sockets on vintage Sonys (mid-70's). This was when FM was new and allowed outboard equipment to decode the stereo or subcarriers.
@@Anon-fv9ee wow, that’s very cool. As fascinating as the Beat Cut issue although I never saw an MPX marking on the many radio recorders I had growing up, unlike Beat Cut which was a constant mystery. I’d love to know what the optional FM subcarriers were used for - audio? Surely not? Do the illuminati have their own commercial free versions of popular radio stations? Military use?
When recording from FM radio it's actually the opposite: The 19kHz pilot tone of the stereo multiplex interferes with the bias frequency or the frequency of the erase head, causing a beat frequency resulting in an audible whine. That's what the MPX filter is for: It's just a notch filter that removes the 19kHz pilot tone and the 38kHz subcarrier.
The 19kHz can also interfere with Dolby noise reduction when recording tapes. I also discovered another use for the MPX filter, some CD's and even LP's were very hard to record, they'd produce distortion on cymbals when recording. Changing the bias and recording levels reduced but would not eliminate the problem. Other cassette decks and even reel to reel would also have the problem. I finally realized frequencies in the cymbal sound were mixing with the tape bias in a nonlinear way and producing an unpleasant sound. I don't know if this was intentional analog copy protection or just an artifact. MPX filter would almost completely solve the problem even though the recording was from CD or LP and not FM stereo.
@@davidg4288 Did this happen mainly with rock music recordings? I guess the reason is because the drum sounds and cymbals are always very compressed on that genre of music making them consistently loud at a relatively high level. That would do it.
@@circattle This was a long time ago, I recall it happening in progressive rock and fusion jazz which was NOT very compressed but did have all the highs they could record. Recording at a lower level did not fix it, it was more frequency than loudness related. I no longer have working tape machines to test with.
A long time ago back when I was a kid I didn't know what that button did, so I tried it and smoke came out! It was obviously faulty but for a long time after that I stayed away from ever using that on anything else that had it.
For anyone who doesn't know, "beat" in this sense can refer to the observable difference between *any* two frequencies, not just audio (although audio is where the term is encountered most often, which no doubt adds to the confusion with the musical homonym.) But for example, if the turn signals on two cars seem to be flashing in sync, but the signal on car A is just a little bit slower and starts flashing more and more behind that of car B, you're seeing the signals' beat frequency
Pilots of multi engined bombers during ww2 used to synchronise their engines to prevent the loud "pulsing" of the beat frequencies between the engines. Allegedly the Germans didn't bother so much and people could tell the difference between formations of German and allied planes because the German aircraft had a distinctive drone caused by the beats.
100%. If it's of interest: before the days of digital tuning meters this is exactly how pipe-organ tuners used to "lay down" the middle octave of a set of pipes, playing fifths and fourths - each interval between 2 notes should have a specific number of "beats" (different for each two notes) in the same way as you describe. Once you've laid the bearings of that reference octave, you then simply tune the rest to exact octaves of each note with no beat audible.
Irc another example is when you see wheels or propellers in films, slow right down or even reverse as the vehicle is moving. This happens because the "frame speed" or frequency of the camera is interacting with the frequency of rotation of the wheel or propellor. When the frequencies get close to each other, you start to see the beat frequency or difference between them. This is what gives the odd looking effects and can often be seen best in old movies with stage coaches or steam trains with spoked wheels.
@@crabby7668 not true. Germans used tiny propelers on their wings that would create siren-like sounds during high speed dives so they can psychologically dominate over people by frightening them further more. Look it up
Finally! The answer to one of those technical quandaries that used to drive me crazy, and an answer I had all but forgotten that I wanted to know. LOL! I wish I had been able to solve this about 35 years ago, but better late than never. Although I am unlikely to ever use one of these switches again, this satisfies me greatly. Great demonstration, too. Thank you! 😁
This video was so nice to watch, I love both cassettes and AM/FM Radio, I used to record music from the air broadcasts of my city on my tapes back when I was a kid, and oh boy, I miss those days with my little and cheap Lennox all-in-one.
My god I had it too in the 80s and never had any idea of what it was! But here in Italy AM radio was never used, even back then. I remember asking my cousin (expert in all kind of audio equipment) and he was like "uh sure that's... uhm... the beat... cut" and changed topic 😂
OK!.... "It's Official" - You are NOW my New Hero! - They NEVER taught is this stuff back at Berklee in Boston in the 80s! - So GLAD I found your channel!!! 🙂
I think it was somewhere around the year 2006 when AM radio was switched off for over here in Holland. I live approximately 15 kilometers from where a big transmission site was, one megaWatt of power and all over the band there were hums and hisses, clicks and tones, everything else was completely unlistenable caused by the disturbance. Recently I bought again an AM radio and to my surprise the disturbance was gone and so where all AM radio stations, I knew that the biggest part of them were closing down, but I never bothered to try. Now there is some talk radio in foreign languages and so now and then a far away station with unrecognisable local pop music. It sounds like going on a holiday, then I always listen to whatever station that is on the air. Recipes and politics in French and people worrying about nothing important. Goodbye AM, it was nice 40 years ago, but not any more.
I'm also from The Netherlands, the last high power AM transmitter here was switched off in 2019: 1008 kHz from the Flevoland transmitter. Originally 400 kW daytime power, only 100 kW or so in the later years. Shortly after the final closedown, the transmitter was demolished. It was a nice piece of engineering, an anti fading antenna transmitting on both 747 and 1008 kHz, 400 kW each. 747 went off air in 2015. Nowadays, several low power AM stations are legally on air all over the country on numerous frequencies, power levels between 1 W and 100 W. Maybe one of them is nearby, maybe you're able to receive several after dark. I like that :) Apart from that, I tune in to Radio Caroline on 648 kHz broadcasting from Orfordness, UK from time to time. One of the few music stations transmitting on AM/medium wave.
@@JesperD87 Yes, it was a year in the two thousand range, the programmes were aimed at elderly women ("de Muzikale Fruitmand" and that programme with Willy Walden and Ase Rasmussen, "Raad een Lied of Niet").
I'm from Bosnia. I sometimes catch a Romanian AM station but they seem to be exclusively a talk show station. Other times, when I'm out in the field, I catch a (I think) military station all the way from Russia at night.
An excellent video. Despite being big into recording I never knew this, but then pretty much all my radio recordings were from FM and like many others I obviously didn't read manuals as fully as I could have. Thinking about it, I feel the switch should really be called AM Whine Cut.
@Vaquero357 But that is superheterodyne beating caused by two stations in close proximity, rather than that caused by the tape bias oscillator. I think the marketing departments of these products wouldn't want to claim they are solving that problem which is actually most of the whistling sounds on AM.
I remember back in 1985 I was 12 years old and had saved up for months & months to buy a boombox costing AU$120 (AU$390 in today's money). It looked a lot like the one you used to show what DC bias sounds like. When I got home I was so disappointed and took it back saying the record function is broken, it sounds all hissy and distorted. So they gave me another unit, different brand, same build. It had exactly the same problem and I took it back again. This time the salesman got annoyed with me: "what are you talking about, it works fine, I can't hear a thing!" I played him the hissy FM recording & he stood there saying he couldn't hear anything. He must have known it was DC bias that was causing it. But anyway I had to keep it. These days I know what the issue was: they were indeed using cheap DC bias circuits in many "cheap" mid-80s boomboxes. Unbelievable that they were charging the equivalent of $400 for such a rubbish product! I was so upset I didn't buy another boombox for 4 years. Everyone's nostalgic for 80s gear now but it was mostly just one massive scam as I remember it. The quality of audio gear you can get for a fraction of the price nowadays is just incredible.
I am your age. I have misophonia, and I have very sensitive ears, but I also have extremely good hearing. I can hear people whispering across a room when I teach classes (I am an RN trainer, and sometimes surprise my students when I hear what they say). The point is, my ears picked up everything when the music coming out of a cassette or record player was good or bad. My parents had both good and bad stereos, and I had a good Walkman growing up. There weren't scams, unless you bought from a less than reputable dealer who gave you a fake product. There were, however, limitations in the technology available back then. We didn't have the dehissers that we have now, the ability to compress like we do now, etc. It was limited in the recording, so the sound coming out was less than ideal, therefore, the sound we heard was less than ideal. Stereo was a newer concept, and the mono songs were being converted. Some hiss was expected, because that was part of the original recording process, and needed to be removed by using the dials on your equipment and dialing the treble and bass, etc. Audiophiles, such as myself, have grown to love the familiar pops and crackles of vinyl. It's the imperfections of recordings that bring them to life. It's nostalgia. If you go back and listen to the original recordings, you will hear those same hissy (and in the case of mono, tinny) imperfections. It is what it is. The music was far superior back then, despite the technological recording limitations. We had creativity on our side. I will take the 80s any day.
Great explanation! While living in the UK, I had a 1980 mono radio-cassette recorder manufactured by PYE. The beat switch was labeled RIF. Later on, here in NJ I received a crappy Soundesign boombox (1988). It had a beat-cut switch.
I truly learned something today. And just because you have spoken about them the under appreciated cheap end stereo systems of the 80s might get the respect they deserve. There were some great systems produced round then, like the Aria FX series, even the cheapest FX 20 came with a neat linear tracking turntable. No kidding.
Wow, never knew that, also think there could be a reason to do a video on bias too, maybe comparing different methods and frequencies, could also record in Audacity and pitch shift so we can hear different AC bias signals, cool!
This was a genuinely good and informative video, even if AM is pretty much dead where I normally live. I just recently even came across beat cut switches and at some point even mistakenly assumed they were for signal rewiring to cancel the centre portion of a stereo song (i.e., cut out vocals on cheap Karaoke systems). D'oh!
Thank you very much this video! For many years I've seen these switches again and again...but never could figure out any difference when turning them to a different position (because I never recorded AM radio).
Many ham radios and high-end shortwave radios have a "beat shift" or "clock shift" as well. The interference is from the local oscillators and CPU clocks. With CPUs, IFs, and internal buses now in the tens to hundreds of MHz, it can affect VHF/FM radio, and similarly, the feature changes oscillator frequency slightly to place the "birdies" off the frequency you're listening to. Most modern radios have firmware that automatically activates this when you punch in a problematic frequency, so you'd never know it's being used.
I grew up in the 80s and 90s. I think I owned (or more likely my parents owned) at least two of the exact stereos shown in this video. I used to record music from the radio all the time. I had no idea what that "beat"/"iss" button did. It only took like 40 years but now I finally understand it!
I remember I found what that switch is for, when I read the manual for my favorite soviet boombox - the VEF 260. That thing is an excellent AM receiver, with the regular medium wave band split in two for better selectivity, so the engineers who designed it put some care in explaining what the bias switch does. The switch has three positions, but what was NOT explained was that it would shift the bias frequency enough to allow recording on chrome tapes.
In the 90's, I inherited my dad's 1982 F100 pickup that only had an AM radio in it (the kind with the 5 preset buttons that go KER-CHUNK when you press them.) The only station I could stand listening to that wasn't Hits of the 50's or hardline conservative talk radio was Radio Disney. But that station always had a high-pitched squeal that directly lined up with how hard I was pressing the gas pedal. So as I was accelerating, the sound would drown out whatever S Club 7 sounding stuff I was trying to rock out to. Now I think I understand what was happening.
I dont even own any tapes, records, or even cds anymore but i love watching your channel on subjects like this! Thanks for all the entertaining and educational videos!
I already knew this... but found it completely by chance, tbh. I actually found it with a faulty bias on a Sanyo G2005. It had support for ferric tapes and metal, but not chrome (why? Don't ask me what they were thinking about when they design it). The faul was a transistor on the oscillator, and when I replaced it, the am station I had it tuned in started to whistle. I took me a good hour of troubleshooting until I found the beat cut switch in the back...
Very interesting. I’ve seen those buttons years ago in the 80’s and 90’s on my old boom box radios but as never recorded off mw radio I didn’t need it not that I knew what it did back then anyway!
Thank you for another interesting and informative video! I use those exact same AM loop antennas that you briefly showed in the video. I was wondering if you’d ever do a video on those types of antennas and the FM ones too, as I have always gotten mixed results using them. It feels like they’re super finicky trying to find the best position for them.
Loop antennas are indeed directional. That's not so good if you're trying to receive stations from different directions, but the advantage is that it also lets you position the antenna to null out interference or an unwanted signal.
In the Uk AM radio started being replaced in the 80s with most major stations swiching in that decade leaving some duplicate stations talk radio or smaller on AM. My recordings back in the 80s I always made off fm stations as they were stereo and no AM stations were. Thus the beat cut swich never got used, though I might deliberately try it out now.😂
Consider that DAB can offer FM-or-better quality within the same bandwidth as an AM signal. The MW band offers better range than FM/VHF/UHF ones; wouldn’t it be handy to be able to put some DAB stations on the MW band?
Great video, I never knew what this switch did either! Since you mentioned long wave, the Irish station on 252 kHz (RTÉ Radio 1) is closing it's LW transmitter on Friday 14th April, less than two weeks away. Not much left although BBC Radio 4 on 198 kHz is still clinging on for now.
I NEVER knew the difference in the sound quality of certain recorders was DC bias vs. AC bias. Holy crud! This video amped up my knowledge in several areas. Thank you!!
It becomes more confusing when, as on a couple of units in the video, the same switch has multiple functions, ie: tape playback eq, ISS mode, and FM stereo mode.
Nice clear explanation. I did always wonder about it back in the 80s but I never recorded AM. Still, it’s nice to get an explanation decades later. Thanks!
Holy Crow; that was a good explanation! Just based on the term "Beat Cut", I would have thought that it had something to do with adding blank sound, before the start of a recording, which wasn't even close.
I still have the only two "boom boxes" I have ever owned, and neither of them have the switch. But, being the nostalgia hound I am, I'm certain I will own one at some point.
Great job explaining that. I myself have always wondered what that was all about. Very cool you had some real life samples and could duplicate the issue. Thanks for the new wrinkle in my brain!
Very well explained. I would imagine that the 'correct' setting moves the beat frequency above the audible range. I suppose it would even have been possible to automate this - with a modern radio tuner having a digital display, there's enough information available to pick a bias frequency that won't beat in the audible range without requiring user input, not that this would have ever been cost-effective in the sort of devices that actually needed it.
I learned now that "beat" or "beat frequency" is what is called in German "Schwebung" - the amplitude changing signal resulting in two frequencies next to each other. The amplitude changing frequency is then approximately the difference of the two involved frequencies (in first order). Was an effect very used by musicians on their analog synthesizers ;-)
Really nice video. I also wondered what this setting was. And wow, you still have a Casio SK-1? That's amazing. One of the very few sampling keyboards and one of the best.
Thanks, VWestlife, for your in-depth video about the beat cut switch. I recall seeing that switch on some of my previous boomboxes from the mid-1980's to the 90's (Prosonic, Samsung, Fisher, etc.) and never understood what it was for. Now I know and knowing is half the battle. G.I. Joe! All the best. :)
😂Wow I don't remember this at all, probably because I would never have used it. But as soon as you mentioned AM radio I knew exactly what it was for 😊I could hear the AM beat in my head, my mom used to listen to a lot of am radio, she was older and AM played music from the 40s and 50s etc. Great video 🖖
I've had a few stereos that had this beat cut switch but I could never figure out what it did. I now know thanks to your video. Back in the 80s my parents had a JCPenney stereo system which was a receiver, a tape deck, and turntable up top. I remember it having those function symbols in blue on your stereo seen in the beginning of the video but clear because they lit up on a gray background when a function is selected.
WAIT A GODDAMN SECOND, the beat from the keyboard at 2:25 is the very beginning from a German Song from EAV called "Burli"! Whaaaaaaaaat... did they really sample THAT keyboard???
I always wanted a SW boom box with a BFO. Beat cutting is fine, and thanks for telling us. But I like to be able to listen to SSB transmissions too. :)
I remember those switches. I think there was even one one, or the markings for one, on a boombox that had a flip-out erase magnet and wouldn't have needed such a switch. The other mysterious switch I remember from that era was the "stereo wide" switch, which emphasized the sounds that were different from left to right, making the stereo effect more pronounced, despite the close spacing between the speakers. It was a cool feature, but if the speakers had been angled out on more boomboxes, there would have been less of a need for it.
Very interesting, I never knew what it was, and I'm 49 years old. I mainly recorded from the FM band, so it wouldn't have been really an issue for me back in the day. AM still going strong here in Australia. They have mainly voice for AM and FM for music with exceptions. I live in Country Victoria and they have a music radio station on AM (531 khz). Nothing beats the range of those low frequency AM broadcast stations.
I can imagine a country the size of Australia needs something better than line of sight for transmission. I once picked up a faint signal from radio Ceylon in Mumbai on a pocket handheld, I remember it was during a power cut back in the 80s so local interference was probably low enough to let it through. still, that signal travelled over a 1000 miles with a few mountains in between!
"...I know this topic may be of diminishing relevance..." It certainly isn't. This is an excellent representation of the phase shift in frequencies that college physics students learn about that you can hear. When you are doing the calculations, it's hard to visualize what they mean. This is a great tutorial.
Me trying to figure out that beat cut switch: Step 1: Presses the mysterious button Step 2: Listens intently Step 3: Nothing happens Step 4: Starts questioning the meaning of life
Always wondered why it was sometimes called an oscillator switch. I’d assumed it introduced a 180° out of phase signal into the tape recording to filter out something from the radio, didn’t realise it was the tape deck’s own bias frequency. Slightly altering the frequency so it’s no longer harmonic makes much more sense than a phase inversion too, especially since you need the switch in one position for some frequencies, another for others, and makes no difference in yet others. Nice demonstration. Also makes your recent poll contextualised ;) I always saw MW called AM or AM/MW here because I’m a child of the 90s, but had figured it was “medium” by means of exclusion from being included alongside SW and LW even though it wasn’t labelled MW on my dad’s fancy receiver.
I've owned several stereos with a beat cut switch, when the time I was about 9 or 10 I discovered that if I was recording on AM radio and played with the switch, I'd hear that whistling noise, I have a recording of a radio program on a tape and I was playing with the beat cut switch while recording, so you hear lots of whistling noises. I remember Mum had a Sanyo portable stereo with a beat cut switch, and I remember recording on it in around 1991 and the switch was set in the wrong place, so all through that recording, you hear that bloody howling noise. I was only 7, so I didn't understand that I needed to change the switch setting. My own tape recorders were DC Bias, so didn't need a beat cut switch. This video makes me wish TH-cam had been around in the 90s. BTW, I love your collection of radios and tape recorders, I wish I had more like that. I have a Sony CFD-S28L that has, I believe, 5 ISS settings, and I never knew what that did. Mind you I've never used that unit to record AM radio, only FM.
Crazy to see my little AIWA stereo/radio cassette deck AND my Casio SK-1 looking in such great condition. Mine look like they've been through a partially successful raid on the Death Star
I have not had this problem (Radio stations here in Norway typically used FM, and those were the ones I recorded off of) but I am still thrilled that I now know more about recording and radio and such. So thank you for that, mr. Westlife.
This is the most useful video on TH-cam I have ever watched, I have a GPX AM FM & tape player, I bought way back in the 80s, "still works LOL", it has a Beat switch on the end by the power input cord, never in my life, could I figure out what it did, thanks to you video, I now can get a good night sleep, without the perplexed worry I always felt from that Beat unsolved mystery
It's interesting to me that that one switch for beat cut on the bigger stereo system is also used for the stereo mode when in FM, and the tape type when in playback mode. I think it would be a pain in the butt to have to keep switching that forth and back depending on what you're doing with and using in what mode, even when you don't have to, just because you had to switch it for something in a different mode.
The "beat" is basically beating two signals together. It's the "B" in BFO, the Beat Frequency Oscillator, which mixes a second signal with a received single sideband (SSB) one to allow it to be heard normally.
there are also cases where the beat cut is omitted and the bias is permanently set and can't be changed. My Philips AZ1310 boombox, as well as a cheap Chinese stereo I have, that is so Chinese, everything on it is in Chinese, both have a bias coil on their tape deck boards, but no beat cut switch.
I haven’t noticed this at all on my HiFi equipment, but I’m sure that some do have something just like this. That actually makes a big difference in the audio, cool to see that it is included on many systems. (Although it’s not super helpful when it has several different names.)
Love the videos!!! Everything you post is both informative and educational. Thanks for taking the time to make these, even if it’s simple stuff. Greeting from Northeast PA
Assuming you could find the manual, Sanyo actually did a pretty good job of explaining what the switch would do. I was quite young when I first saw a boom box with a beat cancel switch, and while I didn't understand the "why" back then, it didn't take long to figure out that toggling it would suppress the whistling that popped up while recording certain AM stations. I picked up one of those Sony boomboxes a while back and was quite surprised they actually included that feature.
Wow! I used to have that very GE boombox at 9:14. that was a good little unit. I had it in my art studio and it was painted with extra paint and a little splattered as well.
Not to be confused with an MPX filter, which rolls off the frequency response around 19 kHz to prevent the FM stereo multiplex signal from interfering with the bias of cassette recorders that can record above 19 kHz. Unfortunately, some high-end cassette decks did not have the option of turning this filter off so you could never record above 19 kHz, even if the deck was capable of it. (Although today I would be absolutely thrilled if I could hear anything above 13K.)
Let me see if I understand it: the FM stereo signal is amplitude-modulated onto a 38kHz subcarrier. This subcarrier is then suppressed from the transmitted signal, and substituted with a “pilot tone” at 19.5kHz, exactly half the subcarrier frequency. This can be picked up by the stereo decoder and used to regenerate the phase-accurate subcarrier so the AM stereo signal can be correctly decoded, and then applied to the mono baseband signal to regenerate the separate left and right audio channels. Not sure why this carrier-suppression scheme was used; something about reducing the overall bandwidth requirements of the signal?
In 2003, I had a dual-well cassette/CD combo karaoke machine and I thought the Beat Cut switch was for the purpose of configuring the meter in proprietary The Singing Machine MIDI CD karaoke songs. For instance, if a song was in 4/4 time, the Beat Cut would interact with the CD player to toggle a 3/4 time signature version.
Great explanation, thanks! I have not recorded off AM in 40+ years but good to know exactly what that little beat cut button did, not to mention its the same as OSC, ISS, etc. 😊
A brilliant video. I always wondered what the hell this function was on portable stereos back in the day, and it was also poorly described. It's been a question circling around in my brain for years. Thanks dude.
When I last visited the USA I was amazed at how good the quality of AM was (stereo in some cases). In the UK AM has always sounded very poor. I would often hear that beating whistle on a stand alone radio without any cassette recorder near by.
Very interesting. I never bothered to record anything on AM (I was a kid when AM was still relevant and I couldn't have cared less (and still can't) about Rush Limbaugh, Baptist revivals, or most country music) so I would've never noticed the BEAT CUT function effects. It sounds like something you'd turn on as a bass reducer, honestly. A better name would probably be AM OSC MODE (AM oscillator mode) or REC INT CANCEL (record interference cancel). At least these suggest what the function is a little more clearly than BEAT CUT.
I had always wondered what that was. I had played around with it thinking beat cut literally meant it cut the drum beat out of a song. Of course it didn't. Thanks for sharing this!
Thank you for making this. Always wondered what it was supposed to do. In UK, in the mid eighties when I was recording from the radio, pretty much all music stations had gone to FM, or VHF as we liked to call it, so no wonder couldn't work out what it did
Fascinating video, I didn't know what it was for either! What I do know is that after seeing this many folks will be flocking to MW, popping in a tape, pressing record and seeing if their old machine rocks a 'beat cut' facility... Let the good times and the cassette decks roll!))
Where were you in 1968 to 1973, when I made all my AM radio recordings? Well, back then, there were all kinds of problems, but that beat interference did plague a lot of my recordings, but I don't think my recorders had any kind of "beat cut" feature. The biggest problem I found back then was if I was in my room trying to record from 93 KHJ in Los Angeles, and someone had the big (25 inches!) color TV on in the living room, that would really mess up my recordings. It took me a while to figure out it was the TV! So, another piece of advice for recording AM radio is to make sure no one is watching a late 1960s tube color TV nearby! And also make sure you don't pick a DJ who really likes to talk over music. (I'm looking at you, ghost of The Real Don Steele!)
I had zero idea what this did. I thought it was to remove low-end bass. Also, here on the east coast of Canada. We have....one AM station left. It's not very good either.
Thank you so much for addressing this! It’s an unsolved mystery from a crappy boom box I had as a child. The completely unnecessary, meaningless “beat cancel” switch. It was only to fill space.
Adding my thanks for the explanation as well. As a young audiophile, I too was perplexed by this switch many, many years ago - for some reason I equated "beats" to "bass" and was wondering why anyone would want to cut the bass. I never did try to record from AM though as my recordings were primarily audio off FM.
It saddens this 52 year old that AM will be extinct in the US in my lifetime. I too, used to record AM broadcasts when I was a kid, most notable the Mighty 690 in San Diego whose antenna was located across the border in Tijuana, MX. Truthfully, I have such fond memories of listening to AM on my Realistic hand-held transistor radio while sitting in my bean bag chair reading the latest issue of Daredevil.
Consider that DAB can offer FM-or-better quality within the same bandwidth as an AM signal. The MW band offers better range than FM/VHF/UHF ones; wouldn’t it be handy to be able to put some DAB stations on the MW band?
We didn't have much AM here in the Netherlands after WW2 , just FM because it had much better sound quality. any advantage of AM (larger distances, I assume?) was not needed in our small country only some pirate radio stations used AM (and some official news channels, but those were also on FM )
I had multiple gadgets with this switch as a kid and never knew what it did. As I never recorded anything from AM radio I guess I didn't need to know anyway!
I have always wondered what the purpose of those switches were on radios from decades ago. I never did record anything from AM onto cassette tapes so I never figured this out. Excellent explanation and demonstrations too!
Obviously they couldn't use "Beat Off" as the nomenclature for that switch.
😂 nice!
It's like on a fishing boat. They never call the person in charged of the bait the "Master Baiter"
They should have called it "Whistle Out"
"Sometimes you just gotta 'choke the chicken' when recording AM radio" ~ every AM radio recording enthusiast ever.
Kinky
Dude. You took the time to demonstrate for the world a puzzling mystery for me and my generation of radio geeks. Thank you!
Agreed. I would’ve paid to know what the beat cancel button meant on my boom box on 1980!
Lol, would have been helpful three decades ago! 😂
I figured it out a few years in to my adulthood and experimentation with radio receivers (building them and such) that they were referring to "beat frequency". But, when I was 10, I was just as perplexed as to what is this "beat" switch for as switching it on or off did nothing.
Before the internet you just had to ask around. Any book at the public library which might have helped was already stolen and that was that. Nowadays no one on You Tube even knows what a library is any more.
Exactly!
I have been tinkering with radios and recording since I was a kid and those devices were new, have a full amateur radio license and have a degree in high frequency electronic engineering AND I NEVER KNEW UNTIL TODAY WHERE THAT SWITCH WAS FOR! Thank you for explaining this unusual but very useful feature. 😅
I think it’s interesting that over the years they didn’t come out with a marketing term that would explain its function better for people who had no idea. Something like “Radio Noise Reduction” akin to Dolby.
Sony got close: ISS "interference suppression switch"
@@rijjhb9467 The term Beat is technically correct it is a beat frequency.
@@GaryKeepItSimple And the technically correct term for what Dolby Noise Reduction does is compansion, but they sure as hell didn't market it as a compander to the general public.
The all new (beat) function allows you to cut the whining noise when recording AM stations lol
Marketing timing 50 years too late lol
Why would they. It's like "2000W PMPO" found on boom boxes in the late '90's, early 2000's. No one actually knew what that meant, either - except maybe for people like me. Another fictitious marketing measurement of perceived output power. It's interesting that they can get 2000 watts from an amplifier that was running on 12V maximum producing under 3 watts.
Having parts of your narration play from cassettes was a really cool touch in this!
This was very well done and explained so you can easily understand. Next, you should do a video on the "MPX' filter button on cassette decks.
Yes, sort of a related topic but different.
Yes please, if anybody can make me understand MPX it is Mr VW 👌
MPX is FM stereo. It works with a nearly inaudible 19kHz carrier tone which could beat with the recorder's bias oscillator. The MPX filter removes this high frequency so this doesn't happen.
MPX is short for "multiplex". An FM signal can have up to 6 signals mixed together - L+R, 19kHz pilot, L-R, 57kHz RDS (scrolling text) plus 2 hidden subcarriers at 67kHz & 92kHz. I've never seen an MPX filter button but it would work on the same principle. I have seen MPX line-out sockets on vintage Sonys (mid-70's). This was when FM was new and allowed outboard equipment to decode the stereo or subcarriers.
@@Anon-fv9ee wow, that’s very cool. As fascinating as the Beat Cut issue although I never saw an MPX marking on the many radio recorders I had growing up, unlike Beat Cut which was a constant mystery. I’d love to know what the optional FM subcarriers were used for - audio? Surely not? Do the illuminati have their own commercial free versions of popular radio stations? Military use?
When recording from FM radio it's actually the opposite: The 19kHz pilot tone of the stereo multiplex interferes with the bias frequency or the frequency of the erase head, causing a beat frequency resulting in an audible whine. That's what the MPX filter is for: It's just a notch filter that removes the 19kHz pilot tone and the 38kHz subcarrier.
The 19kHz can also interfere with Dolby noise reduction when recording tapes.
I also discovered another use for the MPX filter, some CD's and even LP's were very hard to record, they'd produce distortion on cymbals when recording. Changing the bias and recording levels reduced but would not eliminate the problem. Other cassette decks and even reel to reel would also have the problem. I finally realized frequencies in the cymbal sound were mixing with the tape bias in a nonlinear way and producing an unpleasant sound. I don't know if this was intentional analog copy protection or just an artifact. MPX filter would almost completely solve the problem even though the recording was from CD or LP and not FM stereo.
@@davidg4288 Did this happen mainly with rock music recordings? I guess the reason is because the drum sounds and cymbals are always very compressed on that genre of music making them consistently loud at a relatively high level. That would do it.
@@circattle This was a long time ago, I recall it happening in progressive rock and fusion jazz which was NOT very compressed but did have all the highs they could record. Recording at a lower level did not fix it, it was more frequency than loudness related. I no longer have working tape machines to test with.
BNMRR .. Beat Noise Mitigation for Radio Recording!😉
A long time ago back when I was a kid I didn't know what that button did, so I tried it and smoke came out! It was obviously faulty but for a long time after that I stayed away from ever using that on anything else that had it.
So it did what it said, it "cut your beats".
😂
I think you had a Mission Impossible tape recorder
"Beat Cut" is why Edward Scissorhands never looked at naughty magazines
lol
😂
Hahahaha
🥇
🤣
For anyone who doesn't know, "beat" in this sense can refer to the observable difference between *any* two frequencies, not just audio (although audio is where the term is encountered most often, which no doubt adds to the confusion with the musical homonym.) But for example, if the turn signals on two cars seem to be flashing in sync, but the signal on car A is just a little bit slower and starts flashing more and more behind that of car B, you're seeing the signals' beat frequency
Pilots of multi engined bombers during ww2 used to synchronise their engines to prevent the loud "pulsing" of the beat frequencies between the engines. Allegedly the Germans didn't bother so much and people could tell the difference between formations of German and allied planes because the German aircraft had a distinctive drone caused by the beats.
100%. If it's of interest: before the days of digital tuning meters this is exactly how pipe-organ tuners used to "lay down" the middle octave of a set of pipes, playing fifths and fourths - each interval between 2 notes should have a specific number of "beats" (different for each two notes) in the same way as you describe. Once you've laid the bearings of that reference octave, you then simply tune the rest to exact octaves of each note with no beat audible.
Irc another example is when you see wheels or propellers in films, slow right down or even reverse as the vehicle is moving. This happens because the "frame speed" or frequency of the camera is interacting with the frequency of rotation of the wheel or propellor. When the frequencies get close to each other, you start to see the beat frequency or difference between them. This is what gives the odd looking effects and can often be seen best in old movies with stage coaches or steam trains with spoked wheels.
In music I have heard it referred to as "beating" which can be a clearer term
@@crabby7668 not true. Germans used tiny propelers on their wings that would create siren-like sounds during high speed dives so they can psychologically dominate over people by frightening them further more. Look it up
Finally! The answer to one of those technical quandaries that used to drive me crazy, and an answer I had all but forgotten that I wanted to know. LOL! I wish I had been able to solve this about 35 years ago, but better late than never. Although I am unlikely to ever use one of these switches again, this satisfies me greatly. Great demonstration, too. Thank you! 😁
This video was so nice to watch, I love both cassettes and AM/FM Radio, I used to record music from the air broadcasts of my city on my tapes back when I was a kid, and oh boy, I miss those days with my little and cheap Lennox all-in-one.
My god I had it too in the 80s and never had any idea of what it was! But here in Italy AM radio was never used, even back then. I remember asking my cousin (expert in all kind of audio equipment) and he was like "uh sure that's... uhm... the beat... cut" and changed topic 😂
OK!.... "It's Official" - You are NOW my New Hero! - They NEVER taught is this stuff back at Berklee in Boston in the 80s! - So GLAD I found your channel!!! 🙂
I think it was somewhere around the year 2006 when AM radio was switched off for over here in Holland. I live approximately 15 kilometers from where a big transmission site was, one megaWatt of power and all over the band there were hums and hisses, clicks and tones, everything else was completely unlistenable caused by the disturbance.
Recently I bought again an AM radio and to my surprise the disturbance was gone and so where all AM radio stations, I knew that the biggest part of them were closing down, but I never bothered to try. Now there is some talk radio in foreign languages and so now and then a far away station with unrecognisable local pop music. It sounds like going on a holiday, then I always listen to whatever station that is on the air. Recipes and politics in French and people worrying about nothing important. Goodbye AM, it was nice 40 years ago, but not any more.
I'm also from The Netherlands, the last high power AM transmitter here was switched off in 2019: 1008 kHz from the Flevoland transmitter. Originally 400 kW daytime power, only 100 kW or so in the later years. Shortly after the final closedown, the transmitter was demolished. It was a nice piece of engineering, an anti fading antenna transmitting on both 747 and 1008 kHz, 400 kW each. 747 went off air in 2015.
Nowadays, several low power AM stations are legally on air all over the country on numerous frequencies, power levels between 1 W and 100 W. Maybe one of them is nearby, maybe you're able to receive several after dark. I like that :) Apart from that, I tune in to Radio Caroline on 648 kHz broadcasting from Orfordness, UK from time to time. One of the few music stations transmitting on AM/medium wave.
@@JesperD87 Yes, it was a year in the two thousand range, the programmes were aimed at elderly women ("de Muzikale Fruitmand" and that programme with Willy Walden and Ase Rasmussen, "Raad een Lied of Niet").
I'm from Bosnia. I sometimes catch a Romanian AM station but they seem to be exclusively a talk show station. Other times, when I'm out in the field, I catch a (I think) military station all the way from Russia at night.
An excellent video. Despite being big into recording I never knew this, but then pretty much all my radio recordings were from FM and like many others I obviously didn't read manuals as fully as I could have. Thinking about it, I feel the switch should really be called AM Whine Cut.
@Vaquero357 But that is superheterodyne beating caused by two stations in close proximity, rather than that caused by the tape bias oscillator. I think the marketing departments of these products wouldn't want to claim they are solving that problem which is actually most of the whistling sounds on AM.
I remember back in 1985 I was 12 years old and had saved up for months & months to buy a boombox costing AU$120 (AU$390 in today's money). It looked a lot like the one you used to show what DC bias sounds like. When I got home I was so disappointed and took it back saying the record function is broken, it sounds all hissy and distorted. So they gave me another unit, different brand, same build. It had exactly the same problem and I took it back again. This time the salesman got annoyed with me: "what are you talking about, it works fine, I can't hear a thing!" I played him the hissy FM recording & he stood there saying he couldn't hear anything. He must have known it was DC bias that was causing it. But anyway I had to keep it. These days I know what the issue was: they were indeed using cheap DC bias circuits in many "cheap" mid-80s boomboxes. Unbelievable that they were charging the equivalent of $400 for such a rubbish product! I was so upset I didn't buy another boombox for 4 years. Everyone's nostalgic for 80s gear now but it was mostly just one massive scam as I remember it. The quality of audio gear you can get for a fraction of the price nowadays is just incredible.
everything's still a scam.. the target just moved away from sound systems a bit
I am your age. I have misophonia, and I have very sensitive ears, but I also have extremely good hearing. I can hear people whispering across a room when I teach classes (I am an RN trainer, and sometimes surprise my students when I hear what they say). The point is, my ears picked up everything when the music coming out of a cassette or record player was good or bad. My parents had both good and bad stereos, and I had a good Walkman growing up. There weren't scams, unless you bought from a less than reputable dealer who gave you a fake product. There were, however, limitations in the technology available back then. We didn't have the dehissers that we have now, the ability to compress like we do now, etc. It was limited in the recording, so the sound coming out was less than ideal, therefore, the sound we heard was less than ideal. Stereo was a newer concept, and the mono songs were being converted. Some hiss was expected, because that was part of the original recording process, and needed to be removed by using the dials on your equipment and dialing the treble and bass, etc. Audiophiles, such as myself, have grown to love the familiar pops and crackles of vinyl. It's the imperfections of recordings that bring them to life. It's nostalgia. If you go back and listen to the original recordings, you will hear those same hissy (and in the case of mono, tinny) imperfections. It is what it is. The music was far superior back then, despite the technological recording limitations. We had creativity on our side. I will take the 80s any day.
Great explanation! While living in the UK, I had a 1980 mono radio-cassette recorder manufactured by PYE. The beat switch was labeled RIF. Later on, here in NJ I received a crappy Soundesign boombox (1988). It had a beat-cut switch.
I truly learned something today. And just because you have spoken about them the under appreciated cheap end stereo systems of the 80s might get the respect they deserve. There were some great systems produced round then, like the Aria FX series, even the cheapest FX 20 came with a neat linear tracking turntable. No kidding.
Wow, never knew that, also think there could be a reason to do a video on bias too, maybe comparing different methods and frequencies, could also record in Audacity and pitch shift so we can hear different AC bias signals, cool!
This was a genuinely good and informative video, even if AM is pretty much dead where I normally live.
I just recently even came across beat cut switches and at some point even mistakenly assumed they were for signal rewiring to cancel the centre portion of a stereo song (i.e., cut out vocals on cheap Karaoke systems). D'oh!
Thank you very much this video! For many years I've seen these switches again and again...but never could figure out any difference when turning them to a different position (because I never recorded AM radio).
Many ham radios and high-end shortwave radios have a "beat shift" or "clock shift" as well. The interference is from the local oscillators and CPU clocks. With CPUs, IFs, and internal buses now in the tens to hundreds of MHz, it can affect VHF/FM radio, and similarly, the feature changes oscillator frequency slightly to place the "birdies" off the frequency you're listening to. Most modern radios have firmware that automatically activates this when you punch in a problematic frequency, so you'd never know it's being used.
You solved a mystery for me I never knew I had. 😂
I grew up in the 80s and 90s. I think I owned (or more likely my parents owned) at least two of the exact stereos shown in this video. I used to record music from the radio all the time. I had no idea what that "beat"/"iss" button did. It only took like 40 years but now I finally understand it!
yeah... well... who in the 80 and 90's recorded from AM, regardless?
I remember I found what that switch is for, when I read the manual for my favorite soviet boombox - the VEF 260. That thing is an excellent AM receiver, with the regular medium wave band split in two for better selectivity, so the engineers who designed it put some care in explaining what the bias switch does. The switch has three positions, but what was NOT explained was that it would shift the bias frequency enough to allow recording on chrome tapes.
I love these mystery solving videos by VWestlife. Now I know.
In the 90's, I inherited my dad's 1982 F100 pickup that only had an AM radio in it (the kind with the 5 preset buttons that go KER-CHUNK when you press them.) The only station I could stand listening to that wasn't Hits of the 50's or hardline conservative talk radio was Radio Disney. But that station always had a high-pitched squeal that directly lined up with how hard I was pressing the gas pedal. So as I was accelerating, the sound would drown out whatever S Club 7 sounding stuff I was trying to rock out to. Now I think I understand what was happening.
High pitched squeals that change with the engine speed are almost always due to alternator noise. Either the radio or the alternator had a problem.
This video fixed my childhood! And I am pretty sure not just my childhood. Thanks for the explanation!
Thank you for the explanation, my younger self back in the 80's always wonder what the beat cut switch did.
Great video! Thanks for the knowledge!
As an amateur radio operator I immediately recognized the function.
More than 30 years I have been waiting for this explanation. Thank you so much.
I dont even own any tapes, records, or even cds anymore but i love watching your channel on subjects like this! Thanks for all the entertaining and educational videos!
Excellent stuff.
Always good. But, this one in particular scratched a very deep itch.
I already knew this... but found it completely by chance, tbh.
I actually found it with a faulty bias on a Sanyo G2005. It had support for ferric tapes and metal, but not chrome (why? Don't ask me what they were thinking about when they design it).
The faul was a transistor on the oscillator, and when I replaced it, the am station I had it tuned in started to whistle. I took me a good hour of troubleshooting until I found the beat cut switch in the back...
Very interesting. I’ve seen those buttons years ago in the 80’s and 90’s on my old boom box radios but as never recorded off mw radio I didn’t need it not that I knew what it did back then anyway!
I'm amazed and blown away that you even thought of a video like this. Only you Sir and what a great video !
Thank you for another interesting and informative video! I use those exact same AM loop antennas that you briefly showed in the video. I was wondering if you’d ever do a video on those types of antennas and the FM ones too, as I have always gotten mixed results using them. It feels like they’re super finicky trying to find the best position for them.
Loop antennas are indeed directional. That's not so good if you're trying to receive stations from different directions, but the advantage is that it also lets you position the antenna to null out interference or an unwanted signal.
In the Uk AM radio started being replaced in the 80s with most major stations swiching in that decade leaving some duplicate stations talk radio or smaller on AM. My recordings back in the 80s I always made off fm stations as they were stereo and no AM stations were. Thus the beat cut swich never got used, though I might deliberately try it out now.😂
Consider that DAB can offer FM-or-better quality within the same bandwidth as an AM signal. The MW band offers better range than FM/VHF/UHF ones; wouldn’t it be handy to be able to put some DAB stations on the MW band?
Great video, I never knew what this switch did either! Since you mentioned long wave, the Irish station on 252 kHz (RTÉ Radio 1) is closing it's LW transmitter on Friday 14th April, less than two weeks away. Not much left although BBC Radio 4 on 198 kHz is still clinging on for now.
I NEVER knew the difference in the sound quality of certain recorders was DC bias vs. AC bias. Holy crud! This video amped up my knowledge in several areas. Thank you!!
AC/DC
It becomes more confusing when, as on a couple of units in the video, the same switch has multiple functions, ie: tape playback eq, ISS mode, and FM stereo mode.
Nice clear explanation. I did always wonder about it back in the 80s but I never recorded AM. Still, it’s nice to get an explanation decades later. Thanks!
Holy Crow; that was a good explanation! Just based on the term "Beat Cut", I would have thought that it had something to do with adding blank sound, before the start of a recording, which wasn't even close.
Thank you for solving a 40 year old question for me. That switch has mystified me since my first boombox.
I still have the only two "boom boxes" I have ever owned, and neither of them have the switch. But, being the nostalgia hound I am, I'm certain I will own one at some point.
What a fascinating video - today I finally learned what the mysterious "beat cut" was all about! Thanks! 🙂
Thank you VWestlife for making these well done videos on topics few know about.
Great job explaining that. I myself have always wondered what that was all about. Very cool you had some real life samples and could duplicate the issue. Thanks for the new wrinkle in my brain!
Very well explained. I would imagine that the 'correct' setting moves the beat frequency above the audible range. I suppose it would even have been possible to automate this - with a modern radio tuner having a digital display, there's enough information available to pick a bias frequency that won't beat in the audible range without requiring user input, not that this would have ever been cost-effective in the sort of devices that actually needed it.
I learned now that "beat" or "beat frequency" is what is called in German "Schwebung" - the amplitude changing signal resulting in two frequencies next to each other. The amplitude changing frequency is then approximately the difference of the two involved frequencies (in first order).
Was an effect very used by musicians on their analog synthesizers ;-)
The English technical term is “heterodyne”. Also used as the basis for higher-frequency radio receivers (e.g. FM).
Really nice video. I also wondered what this setting was. And wow, you still have a Casio SK-1? That's amazing. One of the very few sampling keyboards and one of the best.
Thanks, VWestlife, for your in-depth video about the beat cut switch. I recall seeing that switch on some of my previous boomboxes from the mid-1980's to the 90's (Prosonic, Samsung, Fisher, etc.) and never understood what it was for.
Now I know and knowing is half the battle. G.I. Joe!
All the best. :)
😂Wow I don't remember this at all, probably because I would never have used it. But as soon as you mentioned AM radio I knew exactly what it was for 😊I could hear the AM beat in my head, my mom used to listen to a lot of am radio, she was older and AM played music from the 40s and 50s etc. Great video 🖖
I've had a few stereos that had this beat cut switch but I could never figure out what it did. I now know thanks to your video.
Back in the 80s my parents had a JCPenney stereo system which was a receiver, a tape deck, and turntable up top.
I remember it having those function symbols in blue on your stereo seen in the beginning of the video but clear because they lit up on a gray background when a function is selected.
I have it on my RCA boombox. Never knew what it was until now.
WAIT A GODDAMN SECOND, the beat from the keyboard at 2:25 is the very beginning from a German Song from EAV called "Burli"! Whaaaaaaaaat... did they really sample THAT keyboard???
I always wanted a SW boom box with a BFO. Beat cutting is fine, and thanks for telling us. But I like to be able to listen to SSB transmissions too. :)
I remember those switches. I think there was even one one, or the markings for one, on a boombox that had a flip-out erase magnet and wouldn't have needed such a switch. The other mysterious switch I remember from that era was the "stereo wide" switch, which emphasized the sounds that were different from left to right, making the stereo effect more pronounced, despite the close spacing between the speakers. It was a cool feature, but if the speakers had been angled out on more boomboxes, there would have been less of a need for it.
Very interesting, I never knew what it was, and I'm 49 years old. I mainly recorded from the FM band, so it wouldn't have been really an issue for me back in the day.
AM still going strong here in Australia. They have mainly voice for AM and FM for music with exceptions. I live in Country Victoria and they have a music radio station on AM (531 khz). Nothing beats the range of those low frequency AM broadcast stations.
I can imagine a country the size of Australia needs something better than line of sight for transmission. I once picked up a faint signal from radio Ceylon in Mumbai on a pocket handheld, I remember it was during a power cut back in the 80s so local interference was probably low enough to let it through. still, that signal travelled over a 1000 miles with a few mountains in between!
"...I know this topic may be of diminishing relevance..." It certainly isn't. This is an excellent representation of the phase shift in frequencies that college physics students learn about that you can hear. When you are doing the calculations, it's hard to visualize what they mean. This is a great tutorial.
thanks for this video, I always asked about it, but I never found a so clear and easy explanation
Nice to know, I remember seeing such a swich and also wondering about the purpose of those loop antennas.
Me trying to figure out that beat cut switch:
Step 1: Presses the mysterious button
Step 2: Listens intently
Step 3: Nothing happens
Step 4: Starts questioning the meaning of life
4:06 - Aww :( I was hoping to hear examples of the same track with too much and too little bias!
Always wondered why it was sometimes called an oscillator switch. I’d assumed it introduced a 180° out of phase signal into the tape recording to filter out something from the radio, didn’t realise it was the tape deck’s own bias frequency. Slightly altering the frequency so it’s no longer harmonic makes much more sense than a phase inversion too, especially since you need the switch in one position for some frequencies, another for others, and makes no difference in yet others.
Nice demonstration. Also makes your recent poll contextualised ;) I always saw MW called AM or AM/MW here because I’m a child of the 90s, but had figured it was “medium” by means of exclusion from being included alongside SW and LW even though it wasn’t labelled MW on my dad’s fancy receiver.
I've owned several stereos with a beat cut switch, when the time I was about 9 or 10 I discovered that if I was recording on AM radio and played with the switch, I'd hear that whistling noise, I have a recording of a radio program on a tape and I was playing with the beat cut switch while recording, so you hear lots of whistling noises. I remember Mum had a Sanyo portable stereo with a beat cut switch, and I remember recording on it in around 1991 and the switch was set in the wrong place, so all through that recording, you hear that bloody howling noise. I was only 7, so I didn't understand that I needed to change the switch setting. My own tape recorders were DC Bias, so didn't need a beat cut switch. This video makes me wish TH-cam had been around in the 90s. BTW, I love your collection of radios and tape recorders, I wish I had more like that. I have a Sony CFD-S28L that has, I believe, 5 ISS settings, and I never knew what that did. Mind you I've never used that unit to record AM radio, only FM.
Crazy to see my little AIWA stereo/radio cassette deck AND my Casio SK-1 looking in such great condition.
Mine look like they've been through a partially successful raid on the Death Star
I have not had this problem (Radio stations here in Norway typically used FM, and those were the ones I recorded off of) but I am still thrilled that I now know more about recording and radio and such. So thank you for that, mr. Westlife.
This is the most useful video on TH-cam I have ever watched, I have a GPX AM FM & tape player, I bought way back in the 80s, "still works LOL", it has a Beat switch on the end by the power input cord, never in my life, could I figure out what it did, thanks to you video, I now can get a good night sleep, without the perplexed worry I always felt from that Beat unsolved mystery
It's interesting to me that that one switch for beat cut on the bigger stereo system is also used for the stereo mode when in FM, and the tape type when in playback mode. I think it would be a pain in the butt to have to keep switching that forth and back depending on what you're doing with and using in what mode, even when you don't have to, just because you had to switch it for something in a different mode.
The "beat" is basically beating two signals together. It's the "B" in BFO, the Beat Frequency Oscillator, which mixes a second signal with a received single sideband (SSB) one to allow it to be heard normally.
Getting that frequency wrong produces some entertaining effects ...
We use those in ADF
there are also cases where the beat cut is omitted and the bias is permanently set and can't be changed. My Philips AZ1310 boombox, as well as a cheap Chinese stereo I have, that is so Chinese, everything on it is in Chinese, both have a bias coil on their tape deck boards, but no beat cut switch.
I haven’t noticed this at all on my HiFi equipment, but I’m sure that some do have something just like this. That actually makes a big difference in the audio, cool to see that it is included on many systems. (Although it’s not super helpful when it has several different names.)
Love the videos!!! Everything you post is both informative and educational. Thanks for taking the time to make these, even if it’s simple stuff.
Greeting from Northeast PA
Assuming you could find the manual, Sanyo actually did a pretty good job of explaining what the switch would do.
I was quite young when I first saw a boom box with a beat cancel switch, and while I didn't understand the "why" back then, it didn't take long to figure out that toggling it would suppress the whistling that popped up while recording certain AM stations. I picked up one of those Sony boomboxes a while back and was quite surprised they actually included that feature.
Wow! I used to have that very GE boombox at 9:14. that was a good little unit. I had it in my art studio and it was painted with extra paint and a little splattered as well.
Not to be confused with an MPX filter, which rolls off the frequency response around 19 kHz to prevent the FM stereo multiplex signal from interfering with the bias of cassette recorders that can record above 19 kHz. Unfortunately, some high-end cassette decks did not have the option of turning this filter off so you could never record above 19 kHz, even if the deck was capable of it. (Although today I would be absolutely thrilled if I could hear anything above 13K.)
Let me see if I understand it: the FM stereo signal is amplitude-modulated onto a 38kHz subcarrier. This subcarrier is then suppressed from the transmitted signal, and substituted with a “pilot tone” at 19.5kHz, exactly half the subcarrier frequency. This can be picked up by the stereo decoder and used to regenerate the phase-accurate subcarrier so the AM stereo signal can be correctly decoded, and then applied to the mono baseband signal to regenerate the separate left and right audio channels.
Not sure why this carrier-suppression scheme was used; something about reducing the overall bandwidth requirements of the signal?
First, also good video Edit: the radio at 0:30 is the one I have!
In 2003, I had a dual-well cassette/CD combo karaoke machine and I thought the Beat Cut switch was for the purpose of configuring the meter in proprietary The Singing Machine MIDI CD karaoke songs. For instance, if a song was in 4/4 time, the Beat Cut would interact with the CD player to toggle a 3/4 time signature version.
Great explanation, thanks! I have not recorded off AM in 40+ years but good to know exactly what that little beat cut button did, not to mention its the same as OSC, ISS, etc. 😊
Wow, my dad had that Sanyo music centre - I now have it as a retro relic - always wondered what that button was for 😂
Obviously, buttons make things better, and that is why buttons were added.
A brilliant video. I always wondered what the hell this function was on portable stereos back in the day, and it was also poorly described. It's been a question circling around in my brain for years.
Thanks dude.
When I last visited the USA I was amazed at how good the quality of AM was (stereo in some cases). In the UK AM has always sounded very poor. I would often hear that beating whistle on a stand alone radio without any cassette recorder near by.
Very interesting. I never bothered to record anything on AM (I was a kid when AM was still relevant and I couldn't have cared less (and still can't) about Rush Limbaugh, Baptist revivals, or most country music) so I would've never noticed the BEAT CUT function effects. It sounds like something you'd turn on as a bass reducer, honestly. A better name would probably be AM OSC MODE (AM oscillator mode) or REC INT CANCEL (record interference cancel). At least these suggest what the function is a little more clearly than BEAT CUT.
I had always wondered what that was. I had played around with it thinking beat cut literally meant it cut the drum beat out of a song. Of course it didn't. Thanks for sharing this!
Thank you for making this. Always wondered what it was supposed to do. In UK, in the mid eighties when I was recording from the radio, pretty much all music stations had gone to FM, or VHF as we liked to call it, so no wonder couldn't work out what it did
Fascinating video, I didn't know what it was for either! What I do know is that after seeing this many folks will be flocking to MW, popping in a tape, pressing record and seeing if their old machine rocks a 'beat cut' facility... Let the good times and the cassette decks roll!))
Where were you in 1968 to 1973, when I made all my AM radio recordings? Well, back then, there were all kinds of problems, but that beat interference did plague a lot of my recordings, but I don't think my recorders had any kind of "beat cut" feature. The biggest problem I found back then was if I was in my room trying to record from 93 KHJ in Los Angeles, and someone had the big (25 inches!) color TV on in the living room, that would really mess up my recordings. It took me a while to figure out it was the TV! So, another piece of advice for recording AM radio is to make sure no one is watching a late 1960s tube color TV nearby! And also make sure you don't pick a DJ who really likes to talk over music. (I'm looking at you, ghost of The Real Don Steele!)
I had zero idea what this did. I thought it was to remove low-end bass. Also, here on the east coast of Canada. We have....one AM station left. It's not very good either.
Thank you so much for addressing this! It’s an unsolved mystery from a crappy boom box I had as a child. The completely unnecessary, meaningless “beat cancel” switch. It was only to fill space.
Adding my thanks for the explanation as well. As a young audiophile, I too was perplexed by this switch many, many years ago - for some reason I equated "beats" to "bass" and was wondering why anyone would want to cut the bass. I never did try to record from AM though as my recordings were primarily audio off FM.
It saddens this 52 year old that AM will be extinct in the US in my lifetime. I too, used to record AM broadcasts when I was a kid, most notable the Mighty 690 in San Diego whose antenna was located across the border in Tijuana, MX. Truthfully, I have such fond memories of listening to AM on my Realistic hand-held transistor radio while sitting in my bean bag chair reading the latest issue of Daredevil.
Consider that DAB can offer FM-or-better quality within the same bandwidth as an AM signal. The MW band offers better range than FM/VHF/UHF ones; wouldn’t it be handy to be able to put some DAB stations on the MW band?
@@lawrencedoliveiro9104 Google for digital radio mondiale
We didn't have much AM here in the Netherlands after WW2 , just FM because it had much better sound quality. any advantage of AM (larger distances, I assume?) was not needed in our small country
only some pirate radio stations used AM (and some official news channels, but those were also on FM )
I had multiple gadgets with this switch as a kid and never knew what it did. As I never recorded anything from AM radio I guess I didn't need to know anyway!
I've never recorded an AM broadcast to experience the oscillation issue but now I know what the cryptic B.P. switch on my boombox means.
I had a 1994 Sanyo boombox back in the day with this switch in the back. Thank you for answering this question after 29 years of head scratching.
I have always wondered what the purpose of those switches were on radios from decades ago. I never did record anything from AM onto cassette tapes so I never figured this out. Excellent explanation and demonstrations too!