8  Acoustics

Resonant Frequencies in Rooms

Rayleigh’s formula for the frequencies of modes in a rectangular room:


where nL, nW and nH are positive integers, including 0, L, W and H are the room dimensions and c is the velocity of sound.

Modal density. If the number of resonant modes N below the frequency f is fairly high then a reasonable approximation is given by


whereV is the volume,
S is the total surface area, 2(LW + WH + HL) and
L is the sum of the edge lengths 4(L + W + H).

Reverberation time (RT, r.t. or T60)

This is defined as the ...

Get Sound Engineer's Pocket Book, 2nd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.