DAMPA whitepaper acoustics - Flipbook - Page 14
Resonance Absorbers
The resonance absorber is an advanced version of the membrane absorber. It still relies on a hard surface, but here,
the key element is the perforation, which are small holes added to the metal plate.
These holes contain ”air plugs” that, when hit by sound waves, begin to vibrate. This movement is counteracted by
the air or porous material in the cavity behind, which acts like a spring, working to return the vibrating air plugs to a
resting state.
The energy driving this system comes from the sound waves, meaning that instead of reflecting back into the room,
much of the sound is absorbed.
As illustrated below, resonance absorbers are effective across a range of frequencies, though less so in very low and
very high frequencies.
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