How BASS Works (In Rooms) - Acoustic Geometry

This video shows what happens to bass - low-frequencies below 200 Hz - in rooms like recording studios, home theaters, and stereo rooms. A six-foot acrylic tube, a few action figures, funhouse glasses, and a tennis ball help simplify the otherwise complicated physics involved in how room dimensions interfere with the sound you hear.
CornerSorbers
acousticgeometry.com/products...
Curve Diffusors
acousticgeometry.com/products...

[@locust108]

I like how I learned something and was sold an ad at the same time.

[@dimitriward1449]

😂

[@ianhosier4042]

I had a stupid cadburys ad - if their chocolate wasn't so bloody expensive I would buy it

[@Stan_the_Belgian]

😂😂😂

[@caiomeirinho6383]

YOU STINK

[@VictoryAviation]

This demo knocks it out of the park explaining the acoustic anomalies associated with smaller rooms. Thanks so much for putting this together.

[@BenBrossMusic]

As a musician who has significant hearing loss, listening to KZbin videos through earbuds for the last three hours, I'm struck by how clear and beautiful the sound of this video is compared to all the other videos I've watched today. Good to know there are people who understand and care about sound.

[@brianabbinanti7021]

Clear, concise, and easy to watch. Love it!

[@mrileeks]

The use of props in this and every other video has been astounding. Props to you sir!

[@johncalder8490]

Ha! Nicely played!

[@naKuhito]

I see what you did there

[@nicholashenry4133]

Like the irony👌

[@YellowWalkman]

Prop squared!

[@warpacademy]

Nice video production. I really liked the visual examples and education on how bass works in rooms. You've said that porous absorption is not effective under 200 Hz though, and that's just untrue. If that was true, and the only thing that worked were pressure-based treatments, then you'd never see professional studio builders filling their rooms with rock wool and fiberglass at depths up to several meters. Those treatments absolutely work, way down to 30 Hz, when you build them with correct depth and density. I can support that statement with a real world experience and acoustic testing data. It's definitely correct that as particle velocity decreases the effectiveness of porous treatments declines, that's why airgaps are used. Even without airgaps, fiberglass can damp room modes down very low in the LF. In my control room we have a front-back axial room mode of 35 Hz that we treated with 1 m of fiberglass and slats. The low end is completely controlled. And of course pressure treatments have their place and use. But it's off base to claim that under the Schroeder frequency you cannot use porous absorption. People like myself are doing it with excellent effectiveness.

[@musergio1]

Keep making these videos! This channel and the people behind it are amazing

[@Acousticgeometry]

We appreciate the kind words!

[@lebohang8405]

Thanks a million John, I saw one of your videos about speaker isolation a couple of days ago and I decided to test it. Went and bought rubber cushions for my mains and sub woofer. The difference is night and day. Magic 👌🏾👌🏾

[@Whitefox-pc7lp]

I'm constantly researching sound related information and so I'm glad that I found this channel!

[@caseym6272]

Found your videos recently and I gotta say, I appreciate every single one of them. It's so cool and informative!

[@sebastianlopeziii]

Absolutely brilliant!! John - thank you so much for your unrivaled advancement of acoustic education on KZbin. Bravo!

[@johncalder8490]

Thanks!

[@duythai5442]

Some of the very best demonstrations! Awesome work!

[@Acousticgeometry]

Thank you for the support!

[@StupidEarthlings]

I wouldn't really call this video "demonstrations" as much as pictures and graphs.

[@auxilix]

You described so many concepts so quickly and well thank you.

[@SideGateStudios]

Love love love this video, well put.

[@YellowWalkman]

This video is actually phenomenal. I learned so much knowledge!

[@VenVile]

This is brilliant and beautiful. Thank you!

[@Pippo.Langstrumpf]

Great description. Thanks

[@DrSamE]

Wow. A video that was actually good info! Props also to testing at NWAA labs, Ron is a valuable source of knowledge!

[@Maynard0504]

I finally understand "bass precision". Great channel!

[@johanvanhuyssteen9217]

Awesome video. Thanks for sharing.

[@MusicLiberator]

yoooooooo this is actually insightful. nice work!!!

[@steveg219]

Nice job on creating a brief explanation of a complex subject

[@drnandakumarakvelu1581]

Real Sounding Video.from massive Efforts..Thank you

[@Aks-jc3bq]

Best Video I Ever seen on YT . Very well Explained Thanku So Much .

[@roitadmor]

The way you teach is very unique

[@babloovyas1080]

Thanks to you for explaining all these facts.

[@chawlamohali]

Beautiful!

[@pingfunk]

Graham Hancock is schooling us on audio now too

[@nkemebenezer]

This video is very helpful. I have learned so much. Thank u lots and God bless you Sir

[@oldmal60]

Thank you. I learned something here can use. Plus your product looks good for my very small need.

[@kingdavidakinyemi]

I love this so much!

[@krsticmilosh]

Thank You this is fantastic video both as knowledge and study.

[@omegahyperes96]

For the love of awesome sound, thank you!

[@anunakigaviria1105]

YOU ARE THE BEST, THANKS FROM COLOMBIA.

[@GunnyPhillips]

A complex topic for sure but this helped me greatly. Thanks!

[@euphoriamusic9802]

very informative , thank you

[@jasonvotaw5966]

Love the action man props!

[@neolyth]

Love this video, thank you

[@keepitup3545]

Thank you so much to be with us ❤️💖

[@cptbamboo2217]

Studying audio engineering and this chanel is pure gold

[@murphyalvin1893]

Hey man, these are also extremely useful resources for studying the science of sound and recording if you're interested. kzbin.infovideos kzbin.info/door/N5UUY5P4IO1nCuQSfo-Uug kzbin.info/door/SCwzZX29jTILlsP4MhjQvg

[@cptbamboo2217]

@@murphyalvin1893 thanks bud!

[@michaelyolch79]

Holy smokes! An engineer with a sense of humor. Very rare! :)

[@norvillerodgersspeaks]

brilliant video.

[@SoundUnitedTraining]

Great video! Very informative and easy to understand.

[@unclejamesx9808]

Wow thats some informative stuff. Thanks

[@thomasriis1987]

Thanks Graham!

[@gaetanobruno5889]

amazing video

[@freereacher]

Excellent!

[@mr.wolfbeats3883]

Thanks for sharing! You're awesome

[@ChrisClark_808]

I just go sit in the corner and wish the whole room was that loud. 😂

[@PerpetuusTenebris]

Same! (Fun fact, by the way, if you put a sub in and facing a corner with an obstruction (like cabinets) a few feet above it, the output is greatly increased throughout the room with fewer noticeable modes. It's the same with putting it under a desk or something like that. The modes even out to give more accurate output. Why do I know this? Testing! How does it work? Reverb I guess. I don't know.)

[@drsumantamajumdar2771]

Brilliant !!.. Thank you Sir !

[@kian3548]

I love how when he says 'bass' I imagine the word having an extreme bass boost to it.

[@mortaldread9379]

Awesome - I'm sold :D

[@arjunxchauhan]

Nice done lads

[@justinbeck8459]

This was great

[@tungbif]

Great videos! Informative and made easy to understand. I'd love to see a video about the acoustics in a round room. I have a such room with a sound system and I'm having a hard time to understand how to manage the acoustics. It seems like the sound bounces in an almost chaotic way to different directions.

[@KingOath]

It still works in a similar way to a rectangular room at low frequencies, except for the length and width are identical every which way, meaning there is one very strong horizontal room mode right in the centre rather than many weaker ones.

[@santoshgujar5237]

Thank you, Sir

[@not_who_you_think]

great stuff yo!

[@ydlp7705]

Yeah science experiment with imperial system.. Gotta love laws of physics!

[@CoreZeroStudios]

This is a great video I sent it to my audio engineers! One of them asked what happens with bass in headphones or earbuds. I know this is not the area that you specialize in but can you think of any place that would cover this topic? Obviously aside from KZbin. Thanks!

[@PotatoflakeJake]

GOD YESS CANT WAIT TO WATCH EVERY FKING VIDEO YOU HAVE THANK YOUUUU

[@InsaneCarville]

Why wasn't this uploaded when I was treating my room for university studies over 2 months ago hahaha. Thank you though, informative as always.

[@blancasusanamariles4655]

2021: Acoustic Engineer consultant Designed my music room w/grand pianos(2) 25x35'. It is not s rectangle but has built up corner absorbers; w/Glass Blocks to absorb 50% Street bus noises. Sound travels 100'/sec

[@paulsarodh5460]

Superb

[@Sykologist_Music]

Nice infomercial! I’ll consider buying two of those if I can afford em.

[@robduff]

Given all this information. What would be the ideal dimensions for a home recording studio?

[@sstefanos00]

Exceptional video! But what have "I" learned??? That I am not going to be able to sound treat my living room unless I buy expensive accoustic panels that must be placed by expensive specialists who know what they are doing....Oh well...

[@johngarbutt]

I agree. Interesting video but no help whatsoever with setting up my hi fi system and in particular my sub woofers. well its back to good old trial and error for set up.

[@jasonLJ]

​@@johngarbutt just buy reputable bass traps, the more the better basically

[@krismichalsky]

@@johngarbutt I agree guys, there is some nice knowledge in here, but as for me and my setup, this doesn't really do much for me other than to play around with my own testing of acoustical materials and where place them in the room and then for the hours of listening tests as in A to B and back to A....

[@TroyTurnerHifi]

I think this video is marketing targeted to the very specialists you mention.

[@chrisw5742]

@@jasonLJ bassically

[@jeremyuzan1169]

Awesome

[@victorygah]

So cool! Thanks. Where I can learn about this?

[@joshcrowe9105]

Awesome content! By chance could you do a video on a round room? Or a Yurt Shape? I am helping a friend build a Yurt recording Studio and struggling to find much information on the general acoustic response of the rooms. Thanks for any help and the great knowledge you've put out! Cheers!

[@johncalder9188]

Round is the second worst geometry for a sound room after sphere. It hugely magnifies one or two frequencies beyond repair. I'd advise against it. Thanks, John Calder

[@keepitup3545]

Love you sir ❤️❤️

[@andyh8239]

Absorbing the room effects... Does that also increase the sound pressures in certain areas that were otherwise cancelledbout by a room effect? I.e. Lower spl at resonance, and higher spl at a null?

[@MarcoAGJ]

Nice.

[@Frietpan]

when i look at the room correction results on my avr i can see there is a huge dip in response at around 80hz from a bunch of channels that dip also did not get corrected by the room correction. is that a room mode problem or a null as the video talked about?

[@adamskatharakis653]

Good selling skills-- I'm totally ready to buy me a nice set of bass traps, even though I only use headphones. ;-)

[@fuuuuuuuguuuuuuu]

And here I was, still subscribed to acoustic fields lol

[@audfrknaveen2256]

Hi ....is the soft copy/digital copy of the book MODERN ROOM ACOUSTICS is available yet ??

[@CobraChamp]

Do your bass absorbers absorb evenly at all low frequencies or do the target the resonance frequency of the room?

[@timmypena241]

You’re an internet hero.

[@snapascrew]

Kinda want to take my homemade tube traps to that lab and have a full test day hahaha

[@onlyKobo]

That tube is so cool

[@kloss213]

You can use multiple bass systems distributed around the room this allows a more even frequency response.

[@joecaljapan]

NWAA Labs gave me a chuckle

[@antesmeridano]

fantanstic music science

[@TriPham-xd9wk]

Would sound high intensity create tsunami too? Possible and by superposition freeway and drainage design accurately could be able to generate tsunami from freeway traffic

[@jcisme]

So these are a broadband membrane absorber ? I thought membrane absorbers only worked in a very narrow band and need to be build to for the room after extensive testing ?

[@christianocean8998]

Amazing !!! The bass is always a problem in the room ... Which is the best bass trap to use in a small 17-18 m2 room ? Thank you

[@johncalder8490]

Hi Christian, thanks for your question! The room modes present in your room would depend on the room's dimensions - how many meters wide by length by height. Divide each dimension by 331.5 (speed of sound at 21 degrees C.) to give you the approximate modal frequencies for each axis (width, length, height). These "Axial Modes" are where your strongest mode additions and cancellations, depending on location in the room, will occur. We prefer to treat low-frequency (LF) modes with broadband absorption (we also prefer not to use the term "bass trap", as it has been widely misused). The combination of our two membrane LF absorbers work from about 45Hz to above 250Hz, fairly efficiently - the ratio of Curve Diffusor (each of which have a built-in LF absorption MLV membrane) and the CornerSorber (a dedicated LF corner membrane absorber) is about 3-4 Curves for each CornerSorber pair. When properly placed at 1/4-wavelength (room dimension) locations along each wall, Curves work very well to diminish modal energy. The CornerSorbers are placed in any room corner. I hope this helps! Thanks again!

[@Akshaibiloniya]

This video is like a bass poetry. ❤️

[@Borderlands808]

Anyone know what happened to “directional sound”? As in only people in front of a speaker can hear what’s coming out of it.

[@awookieandagerman]

Cool video! I wonder if you can talk about some design solutions to these bass problems. Like, what would be the ideally dimensioned room for accurate bass? Or what about a room with no parallel walls? Would that make it easier to achieve accurate bass? Could the walls be fitted with textured shapes that disperse sound, or would it be better to just have them angled away from each other, or maybe both?

[@ericfranke1637]

To answer that, you have to know ahead of time where the speakers and subs will be placed before the room dimensions can be optimized. See Floyd Toole.

[@johncalder8490]

Thanks for your questions! Designing a room without parallel walls and non-parallel floor-ceiling geometry is a great partial solution, and many recording studios and high-end listening rooms do just that. But volume-based low frequency resonances (the same effect as blowing across the top of an empty bottle) will continue to be a problem. Also, due to room crossover, there are no diffusion treatments that will diffuse wavelengths longer than the room dimensions. The best solution to room modes and bass resonances will include combining effective low frequency absorbers with optimal room geometry design (as well as optimizing speaker placements).

[@awookieandagerman]

@@johncalder8490 Thanks for the answer. Is there a program you use to determine optimal speaker placement and absorber placement in a given room? Also does room crossover cease to be a problem if your room is large enough to contain any anticipated bass wavelengths?

[@MykTAOfficial]

That why i love my concrete room as it makes a small bluetooth speaker into a large sounding subwoofer

[@christiantorma2440]

sehr sehr geiles Video 😎🤘😎🤘😎🤘

[@lilgigi8221]

Thanks for sauce, Sir

[@RealHIFIHelp]

Interesting.

[@marcaoliver2965]

Just curious, how does different densities of walls affect the sound, like is are hardwood walls and floors perhaps better than concrete floors and sound dampened drywall, like is there like a preference or just whatever is easiest to control in general is the goal

[@johncalder8490]

Good question! There are differing views, of course. To control low frequencies in rooms, some people hold that the most-dense wall structures are best, some believe semi-resonant drywall structures are best. My own preference is for solid non-resonant walls because it is very difficult to predict how a drywall or other non-dense structure will behave after installation. The stud centers, number of screws and their tightness, whether multiple layers are used (and if Green Glue or similar is used), and other construction variables seem to argue in favor of solid, dense, and isolated walls, ceilings, and floors. Then accurately-tested and effective low-frequency absorbers should be used to mitigate room modes. IMHO. Thanks for asking!

[@JoaoFarias07]

Bass is life.

[@ridefast0]

Hi - I use DSPeaker anti-mode filters with my '20Hz - 80Hz' subs, and I am happy with the results; would I still benefit from corner absorbers or any other pressure-based absorbers?

[@nicolasnaumceski9209]

top !

[@williamchen454]

What problem does the room crossover cause in practical terms? Longer decay times? Problems with amplitude?

[@johncalder8490]

Below room crossover, using fiber-based absorbers is far less effective for absorbing low frequencies than using membrane LF absorbers. The room mode resonances which are responsible for room crossover cause much longer decay times at and around the modal frequencies, which also results in widely varying low frequency amplitudes at modal frequencies at different dimension-based locations around the room.

[@undercrownhiphop9422]

aren’t membrane traps more targeted for a narrow freq range?

[@ahmedzengy]

How can i calculate L shape room mode?