Tuesday, May 28, 2019

Throwing a small ball at a membrane sheet of linoleum


First throwing the small rubber tennis size ball to a bare wall. Ball bounces dramatically, due to mechanical impedance mismatch. Energy reflects back.


Then throwing the ball at a membrane 1m x 1m or so of linoleum spaced from the wall. Ball dramatically freezes (velocity becomes 0 and stays 0).  Ball therefore drops vertically to floor.


A similar situation must be for bass acoustic energy finding linoleum on its path. Linoleum breaks the wave.


A nice 1m x 1m large woofer behaving as an anti woofer.


Energy is absorbed by linoleum ie converted to heat. Energy is dissipated to deform linoleum. Linoleum then gets back to its shape after a while. A nice elastomer hysterisis loop. The temperature of linoleum slightly increases. Good deal.





Linoleum as low frequency membrane absorber was first read on the great book:
Acoustics for Radio and Television Studios  - Gilford - BBC


























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