DIY Speakers and Acoustic Panels
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- เผยแพร่เมื่อ 24 ก.ย. 2020
- We compare different speaker enclosures, the effect of helium on speaker performance and evaluate a wide variety of sound absorbing materials.
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www.techingredients.com/ - วิทยาศาสตร์และเทคโนโลยี
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As an (acoustics) engineer, and a generally curious individual, I seriously appreciate the diversity, depth, and quality of this channels content. While some of the comments pointed out some of the 'flaws' in this video, I think that they are not so important in the big picture. The reason this channel is so great is because they show the experimental thinking behind a creative individual. Thank you tech ingredients!
Just read your comment.
Thanks for saying how I feel better than I could.
Myself saying same thing,
“ thanks for the video, headed to Home Depot”.
Critical thoughtocasting. Proballama slottening. Connecto dotterdings just as pee wee herman says. Connect the slots. La la la la. Injecło bołs na nah nah na. Infect yo hahtrs c lot lotta clołs. Time fo fooorf shlotss. Insanity dots. Nan no bołs. You are now sending out your own wave bending. Mák ad drèss says yes when scännd they all ünknowns man. 7639 code types. Medïcull pröbés?? Hmm whatta ya kniw. Gotta download a bootoof skanner appp as your phone wont unoesss its older and has nfc specific abilities or so,thing. An old android i once had i bet would do it
I agree as a audio enthusiast, and occasionally speaker repair man for my local community and friends
This channel is a gold mine of information, I have acoustical panels (thick compressed wool) in my listening room. And it made a world of difference in overall measurements (almost linear well beyond human hearing range)
Never had it sound this good thanks to videos like this . It makes the audio community forum feel like a , absolute joke (in terms of legitimate information)
I agree completely. It's a "nerds" heaven.
👏🏾👏🏾👏🏾👏🏾👏🏾👏🏾👏🏾👏🏾
An hour and a half ago I was complaining that I couldn't find data-based comparison of DIY soundproofing/noise isolation methods, made with a good understanding of acoustics, and a friend sent me to this channel. This is fantastic.
One of the Best Ideas of SoundProofing is "SoundProof Curtains" That Stops Outside Noise by 80% (25 Db) Tested. Check Here: livesoundproof.com/best-soundproof-curtains/
Me too!
@@laurabrown7556 doesnt work on low frequencies.
Manufacturers of glass or rockwool usually have absorption efficiency's measured and listed and are far more accurate than any DIY methods. That's really the info you need.
@@arpakyna no info beats doing it yourself.
The reality is,
They are trying to get you to buy their product.
Far too many sellers/resellers openly advertise false and misleading info in public, take Ebay for example...
If one was to click every listing for chinese electronics and report each and every one which was not 100% accurate....
Fark.... it would take a lifetime...
In every one of your videos, you answer dozens of questions I've been pondering for years. no hype, no bs, no sales pitch, just the facts! THANK YOU!
100%
It just show that no material is "perfect" for damping, and the ammount of money you put into purdy acoustic treatment panels for your home studio is insane and absolutely not worth the cost unless your a perfectionist and know exactly whats your problem frequencies is or the need of a bass trap at your listening point. The egg shells works pretty well for beeing "free" but so will having just regular carpets and curtains placed around the room, and some bed linnen placed on a hard wood ceiling can remove the worst reflections. Really fun to see all those materials react. It's also pretty inexpensive to just purchase some Rockwool and cut them into manageable blocks and ceil them by sowing some covers for them.
What a complex video to make. Good job, and very interesting results.
Thanks!
I just realized your comment lines right up with the dates you were working on soundproofing your live streaming nook. :D
clive is the fucking coolest!
@@BRUXXUS I just realised TH-cam recommends that I watch the same stuff as Clive, 4 weeks after Clive does.
@@laurabrown7556 why am i not surprised you're just trying to send us to your amazon referral links? how lame is that.
"Human malware event", that's a good one
it's my fav. think it comes from gamers nexus
@@maxlee6676 GN gang
Chinese biology rejects.
Yepper that's the term I'm going to use... that, or the abbreviation: HME!
@@maxlee6676 Spot on. I heard him say it during a video a while ago.
I gutted my house in Brooklyn and at one point it was all exposed walls & ceilings with the Roxul installed.
The acoustics in these rooms was unreal. Your voice would just die in the room. I loved it but unfortunately the wife insisted that the walls be covered in drywall.
Stupid drywall smh 🤣
Couldve got sound absorbing sheetrock
damn, owning a house in Brooklyn, you must be either rich or old
Would consider replacing the wife before the walls but that might just be me. :) j/k ofc
Im working on a office building and almost everywhere is getting double layered 5/8s dry wall with sound glue in between then 1/2 in plywood on top and a layer of finish wood paneling. There is also Rockwool insulation inside the walls. I bet you could scream inside and you wouldnt hear it 1 foot away on the other side
I love the fact that these videos are not sped up. It's relaxing and gives you the time to follow along and digest the information. You're doing a great job! Keep it up!
Thanks!
As someone who's into DIY speakers, I had some issues with the speaker talk in this video. Not that everything was incorrect necessarily, but there were some blanket statements made from this one test that doesn't really even test that specific thing.
The rigidity of the enclosure for example. The anechoic chamber will reduce some of the issues that not-rigid-enough enclosure would have.
Additionally, we don't really know from this test where the line is for this driver. Maybe the first enclosure is completely fine for this driver at these volumes and doesn't need to be more rigid. Saying generally that there's no benefit for it is false.
Another thing that was a bit questionable was the port test. When you design an enclosure, sealed and ported will not be the same size for the same driver. If the idea was just to show that having a port will give you more db in the low end, sure, but I think it should have been mentioned that this is not how you should do it. You don't just add a port to sealed enclosure, you calculate a completely different enclosure volume and then you need to add the volume that the port itself takes up. Also, what fq was the port tuned in the test? Was there a tube even? As it wasn't mentioned in the video, one could think there was just holes drilled to it.
Then there's the dampening in the enclosure. Having the speaker in an anechoic chamber mitigates some of the benefits from the padding. Even if, without it, something would escape the enclosure, it would be absorbed in the walls of the chamber and would not be picked up by the mic. And again, maybe the enclosure itself is already dead enough for this specific driver. So if the dampening worked, how would you know?
With both the rigidity test and the dampening test, you should measure the sound from the side of the speaker, not on axis with the driver.
I do love this channel and I enjoyed the anechoic chamber part of the video, although I think you could have shown it's effectiveness a bit better.
For example: Get a speaker that has fairly flat response, put it in the chamber, do the measurement, use a dsp to get the response as flat as possible and measure it again. This would be the control. Then you take the setup to a normal room and run the test again. This would make it very clear what the chamber does.
As you stated we demonstrated the effect of porting, but did not intend to provide guidance on optimizing porting for a particular driver.
The reason the mic was aimed at the driver was that the enclosure material's effect on the driver performance was what we demonstrated, not how well a particular material blocked the rearward sound pressure.
@@TechIngredients Fair enough.
@@TechIngredients Precisely!
@@vonantero9458 If you're into DIY speakers you might have the same equipment and talent I'm assuming. Would be happy if you could demonstrate your claims in a scientific and measurable way in a video
@Von Antero - I agree with your analysis. I saw several problems with the methods. In my opinion, frequency response isn't something that should be used along to determine the quality of sound. Two different drivers could have nearly identical frequency responses but sound completely different base on cone mass, cone material, stored mechanical and electrical energy, port loading, etc. So saying that the concrete/sound absorber made the sound "worse" in not wholly accurate. liter box with wool will not load the same as a 2 liter box without wool. Still a fun video though; regardless its issues.
the production and content quality of this channel beats all "pop-science" channels combined, with all their "after effects" and schite
Yup, this is quality content right here.
And that's an understatement.
When all you have to show is flashy intro sequences, that's all you have to show. Even then, those intros are SO SO OLD, no one wants to see 2m+ of stupid neon text whizzing around in a starfield with some "music" in the BG.
Engineering bob Ross / mr Rogers, just calmly telling us cool stuff, rather than yelling and shouting
Yup, it's like the difference between a full peer reviewed study and the 'science daily' breakdown of said study.
I leave everything. I put things aside. I give every priority, second priority and start watching your videos as soon as you upload them. These are the best tech videos I have even seen on youtube. Thank you!
Me too! I do this with videos from Applied Science as well, though I wish Ben's videos would be longer. Even though they are long videos I watch them all the way through in one go, unlike many videos from other science channels which are much shorter. It's because I expect to actually learn something new from Tech Ingredients and Applied Science and not hear the same general information about a topic I already know again and again like on the popular science channels. And I also think engineers make the best educational content for some reason.
@@guffaw1711 check out thought emporium if you like content like tech ingrediens.
At least Im not the only one who does that. I saw a new video was posted and stopped painting the kitchen, threw the brushes and rollers in the tub with some soapy water and clicked the play button.
Sheep
I couldn't agree any more with your comment! Thank you!
when you flush with helium you should feed at the top and vent at the bottom
...and that lower vent should be piped back outside the main chamber (or the "door" opened for a short time just prior to the test) to prevent gas contamination in the main chamber.
Then attach a helium-colostomy bag to catch and recycle the helium while its working.
One can learn so much from you in only a single video. I am truly blown away by the sheer breadth of your knowledge Mr. Main Presenter. You are astounding to me.
Thank you very much for taking out the time to shoot and edit these videos for us. I really appreciate it and you. Fred
Thank you and you're welcome!
This man's patience and commitment to methodical science is exactly what's missing in the A.D.D. world of 5-min learning.
Please do not conflate idiotic MainStream Media's proclivity for SoundBitey-ness with actual, clinical AD(H)D.
Those of us with the latter would rather not be blamed for the former
:-(
in the what?
@@mikeclarke952 shorter please!
tl;dr 🤷♂️
@@RogerBarraud I agree! I hate those other youtuber editing their voice so they "talk faster". I got ADD and i love this slow pace in-depth info from Mr. Tech ingredients. :D
Tech Ingredients and DIY Perks are my two favourite DIY channels.
I was trying to remember where i saw the towel panels when he mentioned diy perks :)
Have you guys checked out Robert Murray-Smith's channel? The main focus is around energy generation and storage but they'll discuss other educational diy content.
The thing with the panels, they work better if you don't have them solid to the wall, as then you have the sound travel more distance and like twice the thickness.
@@wobblysauce Yes, double-insulating, constrained layers, airs gaps - call it what you will. They all help.
Incredible how much work and effort you put in these videos. Thanks for sharing these and please keep on doing that. Appreciate it a lot!
I was doing a renovation of a basement that had full concrete walls for the foundation. After framing it out and then adding RockWool insulation I was amazed at the effect it had on my hearing and sound. It was like everything was being muted and silenced the usual background noises present in life … which was extremely discomforting and unpleasant. Not to mention communicating with the others became extremely difficult when we weren’t in near vicinity.
As soon as the drywall went up the entire effect was mitigated and all was back to normal. Watching you put your head in the sound chamber reminded me of the experience but i can only imagine how much worse that chamber was.
According to legend, some workers would have panic attacks when entering an anechoic chamber. I believe it.
Concrete: The expected advantage would be hidden by the anechoic chamber. A problem in speaker design is that non rigid enclosures vibrate (as pointed out in Tech Ingredients previous speaker videos!) - so they produce sound. That sound isn't aimed (mostly) at your mic - so it's absorbed by the walls. If you had a less absorbent chamber, you might see spikes where the enclosure resonates.
For sure. Ears are pretty sensitive and enclosure noise is noticeable to someone critically listening when it's the cabinet ringing and not in the actual recording. Human brain will pay attention to the noticeable frequencies which usual mean louder and sustained ringing from the resonant frequency is easiest to hear. Concrete would if anything be quieter since it so heavy and take more energy to resonate Usually non rigid enclosures are more obvious that its a boxed speaker type sound. Would be good for Tech Ingredients to add a crossover and tweeter and get them sounding decent. Then sit and listen to some test tracks with all those cabinets they made in blind listening tests in a quiet small room. Not the Lab. I think they will notice all those speakers they made with the same woofer sound different in a minor way even though they all measure close in the anechoic chamber.
I came here to say the same. It would probably be easier to see looking at the waterfall graphics, not the frequecy responde chart. But I dont think it would do a huge difference anyway. Also, it would affect the harmonic distortion of the set.
25-30dB below the original sound (direct sound from speaker) is sufficient to our brain to ignore cabinet panels vibrations; that works consistently with music, spoken voice (intelligibility), total harmonic distortion (THD), etc
In the lower frec regions, time delay (waterfall grafics, electrical phase delay and pulse response) are more relevant
@@pedrova8058 The cabinet will be out of phase with the main signal so you will have some interference which can be a big deal at lower frequencies. The main vibration will be in a limited range of frequencies causing a spike or hump and often can be very audible. But it is well established that cabinet vibrations are audible (not subtly). Anyway, wasn't the point to test whether it made a difference? And doesn't an anechoic test make it hard to detect? Check out the Audio Science Review forums and read any speaker review (for a speaker with a crappy enclosure) .
yup, it is, but at higer modes also makes interferences. Thats why damping low and high modes (via stifness, weight, density, internal bracing, viscoelastic materials, very high "pitched" panels, etc) its relevant.
In HiFi world there a lot of "grey" zones in technical evidence (scientific know well correlated with human perception ) ,like power cable effect in response for example (you can measure it, but its imposible to ear it in blind tests); in PA and professional sound studio conditions, the technical info on acoustics and human perception is abundant and well established
21:57..."now I may need a little help from you to feed that helium line in"
Me: mmh, OK, but how do I do that from here?
Also me: oh, he's talking to his son!
Love these videos. Really enjoy them. Thorough, dedicated, and great presentation.
Thanks
He does not mean you, but me.
Why didn't the speaker float if it was filled with helium?
@@chrisreid1644 The buoyancy is equal to the difference of masses between the helium and the volume of air that it displaced. Lets say that the speaker was a 30 cm box, that would contain 27 l of air the density of air is about 1.2 g/l so the box would have 32 grams of air, if replaced with helium as its density is about 0.18 g/l it would have had 4.86 grams instead. So if the speaker and enclosure were less than 27 grams its combination with the helium filing would have been lighter than the surrounding air so it would have floated but they were much heavier so they didn't but a scale would have shown the speaker to be 27 grams lighter (if it was those 30 cm, I am sure that the speakers in this video are some other size). A floating helium speaker might be doable with a styrofoam case and a tiny piezoelectric speaker.
Got a bit of a Mister Rogers vibe from that bit :-)
I had a Dora moment too
Well done, thanks! I'd like to see the result of using soft cotton towels over the mattress foam in your chamber. It seems that they might cause a disruption and dispersal to the waves before and after hitting the foam surface.
Thanks again for another great video!
I am beginning to get the impression that he owns a ceiling tile company.
and his latest inspiration is to sell us tiles hold toilet papers.
I've been watching Tech Ingredients for a couple years and every episode makes me feel nostalgic for my high school Physics classes with Mr. Mathis
Yeah, Johnny could sure sing up a great lesson...
You were lucky so...
You know ......... "Physics is Everything!"?
I’ve been in a real anechoic chamber, the sensation is very strange, you could hear the shift in your microphone when you had your head In The chamber, seems very effective for a DIY chamber
Being a retired old guy myself, I sensed your stress and slight grunt when hefting those speakers around. I offer two suggestions: 1. Swap the positions of the microphone with the DUT Device Under Test. This way the speakers can be suspended inside the shallow door and you won't need the loading floor. 2. let one of your undergrad students do the bull work. Your videos are really awesome and on point. Keep them coming!
Thanks a lot, this will be of great help for improving my recordings!
Note to myself : Conclusion for which type of acoustic panels to use --> 47:16
* floor : carpet
* ceiling : acoustic ceiling tile
* walls : acoustic panels or Rockwool panels covered with a thin layer of cloth (silk or polyester) to prevent the fibers from dispersing into the air
oh i just noticed, 50 minutes. for most content that's too much. way too much. for tech ingredients content well i guess that'll do... could be longer tho ;)
so sad..!
At 2x speed it's only 25 mins
Seems the barrage of adverts filled it out
More? yes please :-)
@@procactus9109 - Firefox has a snap-in to stop the adverts from breaking up the video you're watching. I would recommend this snap-in.
I just want to toss in general support and encouragement-- I love your methodical approach and careful analysis. Keep on doing your thing.
Every single time I watch a new video, I'm absolutely astonished where you get all those ideas and all that knowledge from.
When the host is in proximity to the center of the camber, I could actually hear the difference in audible volume and tone, that the mic picked up. Very impressive!
Love it when ya'll do audio! Gets my EE brain all happy.
This channel really deserves more subscribers. Thank you for the great content.
Discovering this channel has changed pertty much everything. For me the videos are powerful and challenging learning experiences. I liken the channel to meeting a new best friend. By watchig just one and looking at the list of titles I have new ideas and things to discuss with others. This channel makes me even more thankful TH-cam exists today. I have often told others had there been a TH-cam when I was a child my life would be even better than it has been now for 75 years.
Back in the 70's I had the great fortune of my next door neighbor becoming a mentor for me . I'll never forget the experience of knowing a guy as advanced as he is . If I may brag for a second while I remember those days . Dave had two pairs of Bose 901's (series 1 & 2) He had two Wharfedale cabinet subwoofers . A really elegant Nakamichi 700 / 3 head cassette player , a carver pre-amp and a studio quality S.A.E. equalizer , as well as the active Bose equalizers . All of this was coupled by monster cable w/gold fittings . If that weren't enough , he also had a Thorens turntable with the famed 'Rabco' arm . (Every) once in awhile he would ask me to sit in the middle of the room while he played a pink noise album that guided him through the set-up for his SAE . He said my young 17 y/o ears could pick up nuances he'd probably miss . About 45 minutes later we'd be listening to the 1812 overture with live canon fire and all . Man those were good times . I'm 57 these days but that set-up was unforgettable . Thanks for listening .
I've not seen so many adverts in a single video for a long time. Thanks for reminding me to install adblock
I enjoy these optimization-type videos. I'd like to watch you 3D-print, test, and optimize various, unique fan designs with your typical clever thinking.
I used to use fleece blankets tacked to the my walls to deaden the echo in my house. It helped that I tacked the top and bottom of the blanket to a strip of 1x2" wood, hanging it so that it is pulled taught, about a 1/2" off the wall itself. As far as recording, I threw a blanket over my head, and above my computer, draping around my entire desk. The sound was more than marginally improved by this low tech simple use of blankets. Its fascinating to me how low tech materials can be used to produce professional results.
Forget the smoke bombs and the noise(well, not really but just making a point) and keep these awesome detailed, informative, educational videos that are gems. These types of videos are in great shortage on TH-cam. Great work guys, keep it up. It makes me happy to see your channel succeed.
Thanks Tech Ingredients. Even with the background of previous videos, this video could be improved by more up-front explanation of what constitutes a good result (including what the ideal graph looks like)
this channel feeds my intellect, thank you for being thorough
Brasileiro?
Thank you for saving me an enormous amount of testing & time that would have sent me into a sweeping upwards wail. Really, thank you.
I do appreciate the detail you go through these videos. I get a lot out of these, and try to teach these principals to my kids.
Great!
Combining these with the "Active Noise Cancellation" video you made 2 years ago would be useful and cool.
Back then you did promise some updates on the box "in the next weeks" but that never happened.
Ooooh!!! Can't *wait* for the LRAD video!!
The best "DIY Science" video about sound/acoustics I've ever seen on TH-cam! Enjoyed every minute of it!
Really appreciate all the explanations of what you've done and why. Thank you all.
I dived into acoustics year ago having a goal to fix terrible reverberation time (RT60 > 5 sec) in a lecture room. After hours of research over Internet ended up buying absorbing material (panels) to hanger it under the ceiling. But before putting it in place I couldn't miss the chance to check how it would improve acoustic properties of my room at home. So, now I have about 30 measurements done with REW with different number of panels put in different places. Next I'll compare the RT60 curves to see if the results correlate with my intuition and how to actually treat such a small room to get optimal acoustic properties.
Here comes the question: Are you going to compare absorbing properties of materials?
Having the anechoic chamber you can check how thickness of rock-wool changes its absorbing property, how it compares to others (DIY Perks actually tried reduce reverberation time with towels). The best, to my opinion, would be to evaluate acoustic properties of your, say, living room, and fix it if there are some problems, with all this fantastic scientific approach you have.
Thank you again.
Some links you and others can find useful:
* Safety of mineral fibers (a review): www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/347314-comparative-safety-rockwool-fiberglass-organic-fibers-review.html
* Room Acoustic Calculator (many producers, see at the bottom): www.sarooma.de/en/apps/web.html
* Master Handbook of Acoustics, Fourth Edition (PDF): www.researchgate.net/publication/243525251_Master_Handbook_of_Acoustics_Fourth_Edition
* The Sound Blog of Trevor Cox: acousticengineering.wordpress.com/trevor-cox/
Lots of your explanations, make a good sense, and helps ALL learning this technique. Thanks for the tutorial.
2 mins in and i am excited af to see these results
What's up up with the all the TP on your wall?
Oh you know, acoustics and crap.
Would epoxy infused fecal matter be a good acoustic dampener?
@@tiberiu_nicolae could be. Might need to test it.
For when "it" hits the fan.
It cleans the sound?
That TP wall would have been the most expensive to construct of the bunch back in May 2020
This video helps me understand the efficacy of. Low frequency radio and why it is used by the navy to communicate with their ships over vast distances .
They have antennas that are thousands of feet across to pick up the low frequencies.
Thanks for the edifying video !
manners and respect professor, as a young music engineer / artist you show me how fix my listen room , nice one thanks again
Hardly an expert, but I had always thought that both the internal 'stuffing' in speakers as well as the avoidance of ported speakers were to reduce distortion, improve phase response, not to flatten the frequency response, and that using dense materials was to try to make the driver be the only vibrating element, rather than the sides of the enclosure. Your SPL tests don't really address either of these factors, and if I understand how REW is measuring here, it's generating a stimulus signal and either bandpass filtering the response and measuring SPL, or just measuring total SPL, so harmonic resonances here would probably show as 'improvement' or 'no change' even if it sounds horrible? And any off-axis output will be attenuated by your anechoic chamber, and even if it were measured would again just increase SPL even if it results in 'multipath'.
I'm curious to see well thought out and well presented empirical tests like this on these topics. Maybe I'm wrong (and would be interested to learn why these factors aren't!) but I don't think what you've done here has really addressed the reasons that designers choose dense materials, internal stuffing/insulation, or the tradeoff of adding ports.
Totally agree with you. Same goes for concrete vs std enclosure. Measuring spl doesn't say anything. You would have to measure harmonics, vibrations, etc. He could compare concrete vs standard when positioned backwards to the microphone. This could show something. Then again this anechoic chamber does nothing for low frequencies and those will have most impact on case resonance and effect of absorbtion inside enclosure...
I think cabinet resonance gets rapidly more of a problem as the size increases, as the stiffness of a wall falls as a high power of the dimensions, so that the resonances drop right into the most sensitive part of human hearing. Speakers around 40 x 60 x 100 cm would be a better test for this, more the PA speaker size than bookshelf sized.
The whole section on wall rigidity and internal damping completely misrepresented why manufacturers strive for this.
If your objectives is to maximize dB/W by all means follow the advice. If you want fidelity please ignore it.
The acoustic panels section was more useful, however I don't understand why he didn't put the panel he was testing inside his chamber over a wooden panel.
I think you could possibly be labouring under a couple of misapprehensions.
The stuffing inside a speaker in effect makes the cabinet seem larger, it slows down the sound. It also helps absorb resonances and stop re reflected out of phase sound going through the driver cone. It is almost transparent to the re radiated sound from the inside back surface. Which confuses and muddies the sound.
A port or slot, Bass reflex port is to control the cone as it gets to it's resonant frequency. If designed correctly the air mass in the port will be out of phase with the driver when resonance occurs, damping cone excursion and making the output more linear. It also helps boost output when in phase, helping lower frequency output.
BTW. A speaker is the direct opposite of a musical instrument. It should ideally have no character, colour or impart anything extraneous or extra to the sound. That is the goal. Cabinet resonance is a killer. Stiff, solid and dead is the way.
So many considerations are being completely missed, or mischaracterized. For example, there's very little discussion about how the anechoic and partial test enclosures construct and destruct frequency modes (variously mischaracterized simply as "reflection" or "absorption" of sound). There's also nothing mentioned about the T/S parameters of the drivers, esp as regards their performance in sealed vs "ported" cabinet testing. Then using variable smoothing skews the results. This is a great example of someone who has 75% knowledge in the field, discussing things with confidence and conveying a sense of unfounded expertise. A bit of tweaking of his testing process employing the inverse square law could actually yield some legit results.
your channel is amazing! thanks for the high quality content - jarvi
I visited the anechoic chamber at NRK Marienlyst, the national broadcaster of Norway. It is situated in the cellar of the broadcast building, with hallways around it that further insulate it from base sounds. The control room was on another floor entirely. When you got into it, you could hear your own blood pumping in your veins... Which was pretty disconcerting. It's quite big, but I also had to speak a lot louder for my friends to hear me lol. The chamber was mostly used to record samples, sound effects and "clean" instruments for music, where they add reverberation later in the process. The main difference from your chamber, bessides size, was that NRK uses a foot long foam spikes, all from custom materials. And yeah, they got that base insulation covered lol.
Ooh, the long range acoustic projector seems like a nice project to tackle. I really liked this and the other videos you did on speaker designs. Keep up the good work
Towels hanging in 5cm distance to the walls would have been interesting too.
This was interesting but you missed the whole point of high density enclosures. It's not to improve the overall inline frequency response but is about reducing secondary sources of out of phase sound? This of course will be largely lost and barely measurable in your anechoic chamber. I don't live in an anechoic chamber and it will be much more pronounced in an ordinary room. To check , mount a piezo accelerometer to the side of the case (wax, or hot glue if you don't care) then measure the "noise" on the side of the enclosure. This is what's entering the room as part of the sound field and is in direct conflict with the intended sound from the driver. High mass also allows the driver to move fore and aft while keeping the enclosure at rest. physics of action reaction. If you hold the enclosures and feel it vibrate- it's not heavy enough.
I agree with your room treatment recommendations. In the test, your microphone was always at the same standing node as the chamber size was altered with various material thickness. This is why the dips shift around with thicker and thinner treatments. Different frequencies live in Different size boxes.
When you turned the speaker around in the chamber you should not have covered the back. The point being , we don't want any noise emanating from the backside so if it's louder it's bad.
Thanks for another great video and the time spent setting it all up. I enjoyed watching👍
Add to that the fact that different frequencies affects other frequencies in different ways. They can cancel eachother out or they can seemingly boost eachother. When it comes to sound, if it experienced as pleasure or pain, it's a question of how the different frequencies are combined. The combination is allways dependant on what you put through the speakers and the most pleasant sound experience is achived when you most effectively can reduce the unpleasant combinations of frequencies, which also are dependent on the dB for each frequency.
The above is what is used in film and music to affect the emotions, to bring forward feelings of joy, happiness, sadness etc. Different tunes sound in different frequencies with subfrequencies working in subliminal ways that brings your entire body to ring in different frequencies.
That said, I must also add that the toilet paper rolls seems to be the material that most easily could be fine tuned in the environment that they are used.
Living your life in a good sound environment is good your health and if you allways experience crappy sound, you most certainly will be in a worse situation healthwise. The right to good sound should be mandated by law. Crappy sound should not be allowed anywhere.
The point of the rotated speaker experiment was not testing whether the back side of it emits sound, but rather to see how well the wall material of the chamber reflects sound.
@@cschlater "When it comes to sound, if it experienced as pleasure or pain, it's a question of how the different frequencies are combined. " What an interesting concept you describe. What comes to mind is if various sounds add up to a major chord (for a sensation of joy) or a minor chord (for a sensation of sadness), etc.Then depending on where the peaks are, we could end up with a mournful sound or a happy sound. Is that what you are saying?
0dWHOHWb0 Yes. I understand that.
Kirk Creelman, YES that one particular Microphone model's sensitivity curve, mounting suspension and placement (Rx node location) were other variables to test and compare (and maybe adjust for); the test speaker's position (Tx node) would also affect results. Three of the chamber's inside walls could be moved off of those plumb/square 90 degree angles too.
Could electrostatically like-charged dust be suspended within the chamber air, be illuminated by laser or polarized light and photographed to "see" the standing sound compression and reflection waves?
Eliminate all those test chamber reflection challenges by thinking BIG: Take the entire test speaker and microphone apparatus up, way up, a few thousand feet up in the dead air of night, far from city noise source, separately suspended on elastic ropes hanging 100' below two (ground tethered?) hot air balloons. Be sure to also record the balloon separation distance with laser or GPS, the test altitude and air temperature.
I can't tell you enough how much I appreciate your channel. This is the type of DIY project I think about too often and never get around to doing!
*AND I ALREADY HAVE THE EGG CARTONS.* #MuchGratitude
I really like the DIY low cost/high performance approach. I built my home system around a Carver Holographic preamp (1985, bucket-brigade tech) and a half KW stereo amp and ported 2 driver speakers and acoustic panels positioned so reflected sound goes thru them twice. I'm still blown away by the audio hologram; it's got a fleshy, solid image that ordinary stereo can't match; Carver explains it well in the manual. That's my #2 favorite.
But my #1 favorite is the "heavenly voice". It's been around for thousands of years. If you've heard it even once briefly, you'll never forget it. This is tech that belongs to some guys from out of town-WAY out of town. I've got a Bachelor's in sense and perception psychology plus EE and physics, but I've got no idea whatsoever about how this is generated or perceived (do you?). It is loud, clear, with an ambient sound like rushing waters, but it comes from the entire sky simultaneously, as if the whole sky was a giant speaker cone, Clearly this tech predates and outperforms any human tech by a wide margin. It's always friendly, helpful, and reserved (e.g. "That car is following you" (it was); or if i"m done with a lucid dream where they are explaining some phenomenon I'm interested in, a female voice might call my name to awaken me, so I can log the explanation). These guys really like doing this; it's easy, fun, and very educational.
BTW. "Tokio Orchestra Active NEETs" have some great music on TH-cam. Each is miked close about 18 inches away to minimize reflections, nice equipment, each has their own monitor and equalizer. NEET means "neither employed nor being educated nor trained." Most NEETs drop out, stay in their room and play video games all day. These NEETs stay in their room all day to become absolute masters of their chosen instrument, and they are world-class.
Are you a retired physics/engineering Prof? You seem to know a heck of a lot about a lot of topics
He won't tell you. Pretty sure he's an alien. Shhh...
He has said in several videos he is a retired rocket scientist / engineer
"Tech Ingredients" + "Smarter every day" are REALLY REALLY intellectual, educated scientists with incredibly intelligent minds. They put 99% of the go-to, so-called "science" YooToobaz to shame.
Experience shows, and most of them don't know jack.
One think is certain, he is 100% engineering minded. I think an unintended byproduct is that engineers make excellent communicators and teachers. Their way of communication is always clear and concise.
I know, but I won't tell.
Radio Station KORN (from Hee-Haw) used egg cartons in their "sound booth." Thanks for the video!!
Charlie Farquharsen!
@@thedevilinthecircuit1414 THAT's the guy!! And proudly Canadian!
Stumbled across this information while searching for some information about monitor speakers and room optimization (as far as it's possible for the room and budget). The information is clear and interesting. Even if it's not the depth of information I was looking for right now. Understandable language and brought with a "no nonsense" attitude. I like it.
I had read somewhere that the porting is often times a way to use less expensive speakers especially concerning low frequencies because of the additional costs associated with reflex. It noted that the sound pressure is able to be relieved and therefore the speaker design could omit certain steps and features in the production phase. The voice coils are allowed to freely travel unobstructed while the pressure in an un-ported design would require significantly more amounts of precision to construct so they wouldn't bind under the un-relieved pressure. Also in the same article they spoke of tweeter horns having a very specific length tunnel depth to ensure a proper tuning in consideration of the mass of the enclosure and the individual driver specifications. This is necessary to provide proper phase alignment and frequency attenuation. Think of the differences in brass horns and or woodwinds and the physical relationships between them. It's all quite interesting and I absolutely love this video and the work you do. Thank You very much for producing such content. Two thumbs up it's a banger! :)
Your entire shop is so beautiful. I love how big the tall the upstairs portion is. Is that also your mancave in a sense? Did you build it?
Corey - Eugene, OR
Thanks!
Take a look at our video on "The Lab Tour"
Property taxes on something like this where I live would be at least 25000 dollars. No can do.
Guessing from the reverse speaker test your chamber has a slight resonance around 575 Hz. Probably just the right wavelength for the chamber dimension.
The chamber is way too small. You have to use huge anechoic chambers if you want accurate measurements
in the 80's in studio design, we used big 6 foot long, 4 foot wide industrial "dirt trapper mats" hung on the walls. A close weave poly type material on a rubber backing. Stapled at the top and "hanging" free at the sides and bottom. Worked really well an enabled, with the use of a spectrum analyser to get the room frequency response curve pretty much flat. What you heard was what came from the speakers.
Void chambers, in effect a wooden box with a port in it were used to absorb low frequencies... the size of the port centered on the frequency you needed to get rid of.
A happy trip down memory lane. Many thanks.
i have done much of this analysis myself, not in this depth but your results mirror my own. good data is all i can say. thank you.
When are you going to resume the rail gun project? I was really looking forward to it.
2:13 so THAT'S where all that toilet paper went
Best educational channel I know. I'm noise evironmental specialist at my work and yours movies about acoustics are best found online!
Thanks!
Some fascinating experiments. Thanks for taking the time to do them.
4 towels is simply not enough. It should be made just as thick as the roxul . I use 9 towels for absorption panels.
Plus the towels he used looked kind of new. I'm guessing that once a towel breaks in from use and gets all soft it's probably the best time to use them. The fibers have begun to fuzz up and that should enhance their sound deadening ability.
Well, I'm courious how you can read resonances from freq response graph. I'm not sure how exactly REW works, but i assume, that this graph is constructed paralelly to sweep which is playing e.g. when sweep is in particular freq this freq is than written to graph it that exact moment. In my understanding this is frequency response graph. I think you should use waterfall diagrams, to detect resonances, and to test thoose materials. As far as I know waterfall graphs also contains time as third axis, and there you can decet resonances.
I have to suggest Nathan's artiacle about this topic: www.sounddesignlive.com/how-to-measure-and-treat-resonances-like-room-modes-and-standing-waves-with-smaart/
yeah I think there's a fundamental flaw in the final part methods. Besides people care about reflected energy mostly, not resonance
This. He has some understanding of the topic, but his terminology is inaccurate and while his conclusions on a macro scale (the overall idea) have some validity, he is missing some of the details that really show what is going on. That said, the only way to learn is to play with it! I'll never begrudge a man time in his shop measuring speakers!
Agree. Perhaps the general knowledge he has is good, but the presentation fails miserable in conveying real understanding of the principals.
Resonances show up as spikes in a frequency chart, which is also the main reason that resonances are unwanted, they amplify or dampen the sound at the resonant frequency.
@@Anonymous-sb9rr How can you tell the difference between a spike from resonance or a spike from reflections or a spike from driver/cabinet design? More data , particularly in the time domain is required to make educated guesses about what causes each peak.
Excellent video. I really appreciate your thoroughness and analysis.
Your skill at improvised engineering is outstanding!
Thank you!
The helium part... Should have feed the hose in the upper connection, not the bottom one. Helium is lighter than air.
Yes! that would push the heavier air out the bottom.
There is a sound quality concern with porting; "transient response" can degrade vs sealed. Did you use TS parameters to design your boxes? Anyway, transient response would be difficult to objectively measure, but experimenting over time with subwoofer enclosures I can say there is an appreciable subjective difference. Also as far as reflections inside the speaker box, maybe as a future video you could construct and test different shape enclosures? Optimally the panel directly behind the loudspeaker would not be flat. The less flat surface area in the box (all sides but directly behind the speaker especially), the more smoother response overall. (Reference: Loud Speaker Cookbook from Vance Dickason)
Porting hurts and helps. It increases the deflection at a given current, but it returns to center much slower. It's what gives ported bass it's 'sloppy' sound. A sealed sub takes more energy to produce the same deflection, but the vaccuum generated behind the cone will help it return to center, speeding up the response of the speaker, making bass sound 'tighter'.
Ported bass will sound louder at a given wattage, but it will also almost seem lagged and loose.
This is great, thanks! I was just wondering if the towels were a good material to use but glad I came across this video afterwards.
I just came upon this channel today and I'm in heaven 😍 thank you for these thorough and inspired videos
With the vent, the helium is in front of the speaker as well.
>egg cartons
20 seconds in and I already know this is the video to end all "soundproofing" questions
Same thought here. I know, for anything I'd every be playing around with, I'm about to find out the answers to any questions I would ever have and some I wouldn't even think to ask
Thankyou for this lovely vid.. i have a couple of gipes.. When you tested the toilet rolls you didn't have a hard panel attached behind them.. this is the reason for the drop in the midband. Also Cabinet stiffness is extremely important but it's down to spl you are asking the speaker to produce aswell as the tone. At higher spl's the motion of a non ridged chamber's walls will radiate their version of the source material.
Also I would add that introduction of damping material into a sealed bass enclosure serves to lower the q of the chamber, relaxing the LF roll off of the system below the system resonance. You can perform an impedance sweep on the drivers to glimpse the effect. Midrange enclosures benefit from stuffing also as it can be used to ease the severity of modal peaks from the chamber. Much love xx
Love the various tests - great innovative use of materials...
"Human Malware"
Do you happen to partake in the content of a certain Tech Jesus?
Based on viewers suggestions to avoid TH-cam completely broken algorithms auto ban.
He seems like the hammer on box type of guy...
He saying SL-COV-WIV-1 and its genetic modified variants that we are suffering. Aka W#han flu.
Since the helium is lighter than air shouldn't you have put it in the top?
It will still float to the top and push the heavier air out of the bottom.
in audio there's so many myths and believes so i just love when someone comes along and shuts these people up with easy to understand experiments
Thanks for all the information and tests! It's very helpful.
TH-cam ads have become worse than TV...
Install Ad Block on PC and TH-cam Vanced on mobile.
Works like a charm 🙂👍
@@benmoreau6899 TH-cam vanced doesn't work for me. I already have adblock on pc tho
" In space, no one can hear you scream."
Oh come on! Someone had to say it ;)
I have an ex who I wouldn't mind clamping in a soundproof box. She's a singer too.....
I am faced with a dilemma. stay up and watch this, or restrain myself and go to bed. Flipped coin says BED. Oh well.
I'm betting the next event was "Screw you, stupid coin!!11!" and a binge watch of these videos :-)
*continues to watch anyway*
good call, this video at least will probably still be here tomorrow..
UPDATE. I did go to bed, and as I predicted completely forgot I wanted to watch this. So thanks to you all for reminding me I wanted to ;)
@@Godshole haha nice!
I felt like I was in college. I sat up straight and paid attention. He's good. Well done professor. I actually learned something and enjoyed it.
Thank you. A++
Excellent, informative. I'm building my home system and need and appreciate all the information I can get as a novice. I have looked for a concise video of the physics of just how audio systems function - input signals, preamps, amps, out puts etc and not finding that, am putting together videos and articles that I find informing. This was among the best and most informational. Thanks so much. I'm subscribed and looking forward to more...
31:10 Were you just talking during that sweep?
:-/
Good catch
Yea i hope it was voice over :)
@TechIngredients I appreciate that you are trying to make these fundamental acoustic principles and measurement techniques accessible to your audience. The most relevant aspect when doing measurements is to be aware of their limitations in particular under not "ideal" DIY conditions. Knowing the specific limitations helps of course to identify aspects that can be read with more or less reliability from the gathered data. Therefore, I have a couple of remarks regarding the measurements that you present in the video.
The information that you can gather on low frequency content in your anechoic chamber is limited. This is due to mainly four reasons:
1) Limited insulation from low frequency influences from the outside the chamber.
2) Limited efficiency of the porous materials to absorb low frequency reflections within the chamber (below lambda/4).
3) Strong influence standing wave reflections (room modes) at low frequencies within the chamber (above lamda/2 * N for integer multiples of the individual chamber wall dimensions) ... At least the first couple of modes will be present in the chamber.
4) Influence of near-field effects (sound pressure and sound velocity are not in phase) towards lower frequencies due to the limited distance from receiver to source.
As observed, these points mostly limit the reliability of your measurements towards lower frequencies. You could try to determine the lower limit of your measurements based on the theoretical models that I mentioned before or by conducting repeated test measurements in different arrangements where you would not expect the results to change. This would also be a valuable information for your viewers.
The placement of the source and the receiver very close to the walls is also not optimal. This means traditional techniques to omit the influences of adjacent surfaces, e.g. windowing of the acquired impulse responses in time domain to cut out reflections, cannot be applied. But to be fair, there is not much you can do about that with the limited amount of space.
Overall, I have some recommendations in order to improve the reliability of the anechoic and lab reflection measurements:
1) Employ averaging of multiple measurements of each individual condition. I believe this can be done automatically by REW. This help do eliminate anomalies in individual measurements as well as suppress influences from acoustic and electric noise (gain in signal-to-noise ratio due to coherent vs. incoherent addition).
2) Shorten the measurement sweep length since long sweeps are only required in particularly reverberant environments (which you don't have). This is especially relevant in combination with the suggestion before to employ averaging. By shortening the individual sweeps you can still achieve measurement results in a time efficient manner.
Also remember that the magnitude spectrum of the gathered measurements is only half of the information. Depending on the application it is also very helpful to look at other representation in order to understand the full picture. I believe REW has the appropriate tools included, e.g. for the following two aspects:
1) Part 1: comparison of wooden and the concrete speaker housing. It might be helpful to look at a waterfall representation in order to see if there is a difference in the decay pattern of the two cases (specifically at the cavity resonance frequencies).
2) Part 2: comparison of different absorbing wall materials. There could be some insight in looking at the impulse response representation in order to see if there are differences in the reflection patterns of the different materials.
So much effort! Thank you sir for keep doing this. Looking for the DIY Perk towel explanations! Exactly looking for that.
I appreciate very much your making these videos. I will probably never apply any of them directly; I'm here to observe your teaching ability, which I think is remarkable. Well, and the subject matter is very interesting too!
I really enjoyed this video and thank you for including the helium experiment. The results were very interesting. Keep up the good work!
Thanks as always, you guys do such a good job. straight forward, educational, practical, and helpful.
Thank you for sorting this out with egg cartons!
I myself am thinking of wool blankets, they are heavier and have previously been used as filling for speakers ...
Great stuff. Has given me a lot to think about in regards to my own home studio.
This was very cool video. A bit long but was informative and I understood all of it. In my younger days I did Live Sound Reinforcement for indoor events and used very similar tools to tune the EQ's for the rooms we were using. The sound difference is quite amazing when you properly tune a system to the room and then fine tune once the audience is in place. Did this for almost ten years for a great company called RMS (Results in the Management of Sound in Hollywood, California) and yes the name is a play on the word Root-Mean-Square. Unfortunately they went out of business in the mid to late 90's.
Mr. Tech you are amazing. Thank you for sharing your projects and interest.
Every video I watch on this channel leads me to watching another one. I may just end up never sleeping again.
Really awesome work! Loved every minute of this video. This was recommended to me from fellow audio producer after we were talking about how to treat my living room. Am blown away by how much good honest testing is going on here. And as if anyone could moan about your anechoic chamber, some people would still find something to moan about if the sun were shining and you handed them a million dollars. That chamber is awesome. I listened to this video on good big can headphones. when you kneeled in the chamber to place the speaker, you talked to the camera and the room sound went away and I hadn't realized how much room sound there was up till that point. That chamber is amazing.
Subscribed and about to binge this channel!
Thanks and welcome!