New Research Into Sound Suppression

[John Ludlow]

For all y'all who have personally dealt with the issues of sound suppression in the studio, here's an article from MIT on a new fabric that is part silk, and part piezo-electric, that they say is being used to reduce sound by as much as 75%. The fabric is said to function in a role similar to noise-cancelling headphones in which an out of phase signal is produced to cancel out the original sound. Or, anyway, that's their first example.

When I think about it I wonder how they generate a signal that is exactly 180 degrees out of phase with the original? I would suppose that a delay would have to be built in to account for the sound waves traveling a distance from the source, and that would imply that all sounds to be muted originate the same distance away from the fabric. I guess maybe that works for studio monitors, but I don't see how for two performers, or a drum kit.

In their second example though, I think maybe they use the piezo to absorb the disturbance on the silk by turning it into electricity and shunting it off. In that case, no preemptive canceling signal would be necessary. But, I might be wrong - I don't think the author seems all that clear about what they're doing in that second example.

Still, though - interesting technology. I could see it solving a lot of problems. Maybe someday...

https://news.mit.edu/2024/sound-suppressing-silk-can-create-quiet-spaces-0507

[jmh]

Hi John,

This is pretty interesting. I was getting set for a post to wonder about the frequency response, when I hit, 'Moving forward, the researchers want to explore the use of their fabric to block sound of multiple frequencies.'

It is kind of funny all of the room mode issues I had commented about are usually set into motion by a couple of 7" cones moving a fraction of an inch. After that energy bounces around the room getting adsorbed or cancelled here and there, it seems by the time it propagates an audible node, the actual motion of the air particles has to be minuscule. It seems plausible that if that piezo material turns the mechanical energy into electricity a resistive component could turn it into heat. Unfortunately the reduction of fossil fuel consumption in cooler climates would be offset by air-conditioning demands in the warm seasons.

My little joke reminds me of an another forum, having a thread talking about large format consoles generating a ton of heat and needing cooling fans - something I've never considered when I've thought it would be cool to have one of those classic boards - but I'd find the heat and noise aspects annoying.

John

[John Ludlow]

It seems plausible that if that piezo material turns the mechanical energy into electricity a resistive component could turn it into heat. Unfortunately the reduction of fossil fuel consumption in cooler climates would be offset by air-conditioning demands in the warm seasons.

Hi back, John,

Yes, yes... if only we could convince the third world to play enough loud music - the rich/poor energy imbalance could be rectified. Perhaps it could even take the place of fossil fuels! EVs with loud stereos powering themselves. Need to go faster? Screw in the earplugs and turn it up...

John