Symphony Hall, Boston (1900)- good ìshow boxî:
dimensions 45m long, 24m wide, 17m high
early lateral reflection: distance to side wall 12m = 35msec
shallow balconies.
reverb time (1000Hz) 2.05 sec
example: calculate average absorption of walls
2.05 sec = 0.161V/A A = Saave
V = 18740 m3 -> A = 1472 m2
surface area of walls, ceiling, floor approx S=4500 m2
thus ave absorption of walls a= A/S = 1472/4500 = 0.32
example of application: what is effect of carpeting the aisles?
a increases from 0.03 (concrete) to 0.37 (heavy carpet
on concrete) over about 15% of floor area (homework)
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