Originally Posted by Anderson
A membrane-type of resonator looks like a big box or semi-cylinder, usually rather tall/large, which usually has a membrane as a front panel. Sometimes the membrane is hidden behind a wooden front panel. There can also be two membranes.
Anyway, a standing wave at the resonant frequency of the resonator, will cause the membrane to vibrate in sympathy to the standing wave, and "absorb" the standing wave with a much higher efficiency than a Helmholtz resonator. The larger the volume of air, the lower the frequency.
They are harder to calculate, but worth it. Since they are very efficient!
For control room use I've heard that membrane resonators don't work well at low volume since they need high energy to vibrate. Is this so? Can anyone confirm this?