thinner diffuser article

Would the exposed flat surface area over the different chamber inlet openings be more reflective than the older design because of more surface area?

Has this been done before?

https://phys.org/news/2017-06-diffuser-ten-thinner.html

It looks that it is efficient in a very narrow frequency range. I would like to see a chart of absorption in whole audio spectrum.  I'm not optimistic.

Gus said:

Has this been done before?

Click to expand...

Maybe.
http://www.lydogakustikk.no/schroeder-diffuser-using-a-metasurface-new-idea/?lang=nb

moamps

Thank you for the link.
I often wonder if papers about "new" discoveries that people publish might have been done before .

Gus said:

moamps

Thank you for the link.
I often wonder if papers about "new" discoveries that people publish might have been done before .

Click to expand...

The ancients are constantly stealing our new ideas.

The other question is does it really work as claimed for general applications.

JR

Gus said:

Would the exposed flat surface area over the different chamber inlet openings be more reflective than the older design because of more surface area?

Click to expand...

I would say, to me, it's not a Schroeder, it's a scattered Helmoltz. Schroeder is based on closed-pipe resonance that depends only on length. Helmoltz is based on a mass of air resonating against the compliance of a volume.
One of the possible drawbacks is that the wave-speed in the aperture reaches the turbulence speed, where the resonator is so damped it doesn't do anything good. That would limit the range of useful SPL.

Note that the article says it "works". Nothing about how well it works.

I call BS for research-grant-nutrition

Jakob E.

Here is the published paper: https://journals.aps.org/prx/pdf/10.1103/PhysRevX.7.021034