New approach to sound treatment

[Doug Young]

Interesting article, mostly talking about noise suppression, but it seems like this technology might also help with room acoustics - someday... "Acoustic Silk"!

https://news.mit.edu/2024/sound-supp...et-spaces-0507

[b1j]

I wonder how the fabric could distinguish between unwanted sound and the sound you're trying to record.

[Bob Womack]

The major thrust in this study seems to have turned to transmission suppression, ie. keeping sounds from moving from one environment to another. If they are able to do so, it could be revolutionary.

I work in a state-of-the-art listening and recording environment. To keep outside noise out and inside noise in, the engineers had to build a shell of three walls, each comprised of three sheets of 3/4" sheet rock glued and screwed together. Each wall has its own studs and there is now connection between the walls. Each wall rests on a rubber gasket that absorbs rather than transmits sound. There are ten-inch spaces between the walls and the walls are treated with insulation within the spaces.



Each of the rooms is built in this way and each room is built upon a floor floated on a carpet of rubber blocks lying in Owens Corning insulation. Now think about that: there are six walls between the control room and the studio. All of that is built in order to keep the sound from the outside of the complex out and keep the sound from inside each room in the complex in. The principles involved are that wall rigidity, dead space, and absorption work together to attenuate sound transmission.

Imagine if we could erect two or three thin walls of this active silk between two exterior layers of sheet rock to create a wall that divides the rooms and attenuates the transmission of sound between. It could reduce bulk and possibly a bunch of cost.

Bob

[ACOUSTICDEWD]

I like the illustration of the guy sleeping in the same room as a live drum kit performance, separated only by an acoustic curtain. The transmission of lower frequencies will 100% need bulk and density to be reduced. Totally eliminating said frequencies will 100% require a decoupling of these into two rooms. The arrogance of thinking otherwise is appalling but MIT can change the laws of physics apparently.

[jim1960]

Originally Posted by ACOUSTICDEWD

The arrogance of thinking otherwise is appalling but MIT can change the laws of physics apparently.

I think you may be setting up a strawman here. There's no claim that the laws of physics have been broken or even require modification and I read nothing in the article that sounded like the creators were relying on the supernatural (which is what would be required to defy natural law). Incredible advancements come out of MIT all the time so there's little reason to think they're just making up the results in this case. Throughout our history, there is example after example of something once thought impossible becoming possible ...even things that seemingly defied the laws of physics.

Originally Posted by b1j

I wonder how the fabric could distinguish between unwanted sound and the sound you're trying to record.

Doesn't sound like it has to. It's changing what transmits from one side of the fabric to the other. If you're in a room recording, I'd think you'd be fine so long as you don't put that electrified fabric between the mic and the sound source.

[KevWind]

Originally Posted by ACOUSTICDEWD

I like the illustration of the guy sleeping in the same room as a live drum kit performance, separated only by an acoustic curtain. The transmission of lower frequencies will 100% need bulk and density to be reduced. Totally eliminating said frequencies will 100% require a decoupling of these into two rooms. The arrogance of thinking otherwise is appalling but MIT can change the laws of physics apparently.

I would think that the use of "bulk and density" and "decoupling" are some of the standard practices for sound proofing and likely not considered an actual "law of physics"
I would tend characterize MIT as engaging in "progress minded research " as opposed to "arrogant thinking" - But that's just me.

[b1j]

In a way, this reminds me of windows that can go dark (opaque) with the press of a button. Completely different principle, I guess, but analogous.

[kurth]

look at the funding...know what they're really up to.

[jim1960]

Originally Posted by KevWind

I would think that the use of "bulk and density" and "decoupling" are some of the standard practices for sound proofing and likely not considered an actual "law of physics"
I would tend characterize MIT as engaging in "progress minded research " as opposed to "arrogant thinking" - But that's just me.

And me.

If we tried to list all the inventions created at MIT that have influence in our lives, we'd be here all week. Yet, for some, controlling sound is a bridge too far, and I don't understand why we'd saddle ourselves with arbitrary limitations like that when our history is replete with examples of us smashing through previous arbitrary limitations.

[KevWind]

Originally Posted by kurth

look at the funding...know what they're really up to.

Huh ? The article itself already gives a brief overview of what "they are really up to".
i.e. Developing an ultra thin noise cancellation sound proofing layer apparently using electronics
The sources of funding suggest nothing more or otherwise

Kinda blatantly obvious why some of the sources of funding like the DOD the NIH and Private industry (especially construction) would have an interest is such research. There is no funding related mystery to "know what they're really up to"

[srick]

No politics please.

[Jamolay]

I wonder about the “sound mirror” effect. Blocking sound that efficiently would make life pretty difficult for the drummer on their side of the curtain.

I guess that helps reduce the noise on the sleeper side. No one wants to make any noise with a fully reflective wall. It is bad enough playing guitar near a large window.

[KevWind]

Originally Posted by Jamolay

I wonder about the “sound mirror” effect. Blocking sound that efficiently would make life pretty difficult for the drummer on their side of the curtain.

I guess that helps reduce the noise on the sleeper side. No one wants to make any noise with a fully reflective wall. It is bad enough playing guitar near a large window.

Indeed but it sounds like "sound mirror" mode is an additional possible but different effect than the sound suppression mode and obviously not what one would want for a music or recording space

From the Silky Silence paragraph in the article
"They control the vibrations of the piezoelectric fiber so that sound waves emitted by the fabric are opposite of unwanted sound waves that strike the fabric, which can cancel out the noise.".

Reminds me of sort of like the Null effect when playing back to audio files with switched polarity

[kurth]

Originally Posted by KevWind

Huh ? The article itself already gives a brief overview of what "they are really up to".
i.e. Developing an ultra thin noise cancellation sound proofing layer apparently using electronics
The sources of funding suggest nothing more or otherwise

Kinda blatantly obvious why some of the sources of funding like the DOD the NIH and Private industry (especially construction) would have an interest is such research. There is no funding related mystery to "know what they're really up to"

let me know when they make the first recording studio with this technology Kev....

[KevWind]

Originally Posted by kurth

let me know when they make the first recording studio with this technology Kev....

I would not hold my breath, I'm guessing practical application is a few years out at best