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Originally Posted by 666666  A bass trap needs to accept and absorb sound waves, how is this directly correlated to air movement and being able to "blow through" a bass trap membrane? When standing in front of a source of sound, one does not typically feel air moving. |
You're asking about absorbing sound, not blocking sound. Sound is not air motion like you feel standing in front of a fan. In that case the air actually moves, so air over a smelly garbage can travels across the room to your nose. But with sound waves, the air molecules bump into each other rather than physically travel. So it's more like someone at the end of a ticket line pushing the person in front of them, who pushes the next person, and so forth. The guy at the end of the line never gets to the front of the line, but the
energy of his bumping does go to the front.
None of this has anything to do with blowing through a membrane, which doesn't happen anyway. But it explains how sound travels, and why it's not the same as air flow. Being able to blow through fabric is a simple test for reflectivity, which lowers HF absorption. It's not the air flow that actually matters, but it's sort of related so it's still a useful test.
--Ethan