3D printed spiral sound killer

[Pano]

This looks rather intriguing. The linked article is poorly written, but the idea is cool.
I've requested a copy of the paper, would like to know in more detail what they've done. Looks like nested spirals.

BU researchers develop 'acoustic metamaterial' that cancels sound | EurekAlert! Science News

 

[avincenty]

I can imagine a custom fitted 3D printed unit on the back of a dipole OB driver magnet to make it cardioid. Kind of a shallow lxmini top driver.

 

[turk 182]

my wife say's she wants one made like a muzzle....what's up with tha....wait a second!

cool article
if this stuff works in strips...what that could do to resolve diffraction issues... we could go back to square box construction...no more round over worries!

 

[Godzilla]

Noise cancelling 'shape'

I was curious about this technology after reading the article but after watching the short video I wondered if all that's happening here is the tuning of the port... Can someone explain what's happening here?

Mathematically perfect rings could soundproof the world

 

[chris661]

Difficult to say exactly what's happening without seeing photos of the prototype.

Even then, they've managed to block most of the sound coming out of a plane wave tube. It's a start, but transferring that to large-scale deployment will be a hideous challenge.


I suspect a Helmholtz resonator also blocks a lot of sound. A rubber bung in the end of the tube would do very well.

I'd like to see attenuation vs frequency of their plane wave tube.

Chris

 

[Bicicletta]

Yes, it seems tuned around 480Hz.
Maybe nested damped pipes resonant at 1/4 wavelength (17cm).

 

[martin clark]

An application of Helmholtz resonation.
Not broadband-applicable.

Old news, except the implementation - which might be useful yet.

 

[Pano]

I have not heard from the authors. I requested a copy of the paper, but no luck.

 

[Bicicletta]

Have you looked at the images?

Phys. Rev. B 99, 024302 (2019) - Ultra-open acoustic metamaterial silencer based on Fano-like interference

They are quite explanatory.

The artifact has a diameter around 17cm, 7 tubes are a circumference long. They emphasize the qualities of the material, probably with damping capabilities. And the angles involved: perhaps they rely on friction.

I would like to try something similar on the length of an LT, to be used for marital multimedia.

 

[turk 182]

after rereading the article it does seem to be a broadband device, music was used and everyone could hear it after he removed the ring and noise can contain several frequencies which is why helmholtz resonators (like current muffler tech) do not fully resolve the problem.

 

[Bicicletta]

The (damping) six septa that separate the ducts are stressed by out-of-phase waves.
Maybe the relative position of the six ports matters.