Dear David,
Am 07.03.19 um 20:49 schrieb David W. Jones:
I took a short look at the cited publication, Phys. Rev. B99, 024302.
While the device is surely interesting, it won't help you in studios.
You can put the ring on a tube to block a small frequency window.
The device is based on on Fano-resonance and is there relatively narrow.
In the publication the centre frequency of the near perfect damping
is ~ 460Hz, and a width of ~20 Hz (estimated from the figure).
So this might be interesting to filter noise from an air-conditioning,
which may make managing sound a bit easier during a hot summer,
otherwise it won't help much.
Best regards,
Peter