Based on:		Where: Fb = Helmholtz box resonance c = wave velocity       (1120 ft/sec, 341.4 m/sec) A = duct area L = duct length d = duct diameter V = effective box volume
Vgross = L x W x H,   Vnet ≈ 0.9 Vgross  (gross less basket, port, bracing, etc.)  With lavish damping material (eg: fiberglass insulation),  V = 1.4 Vnet For vented enclosure with moderate damping material,  V ≈ 1.12 Vnet

Ref:

1) Fundamentals of Acoustics - 2nd Ed Lawrence E. Kinsler & Austin R. Frey © 1962 John Wiley & Sons, Inc. (p. 187, 193)

2) American Institute of Physics Handbook © 1957 McGraw Hill, Inc. (p. 3-104)

Last tinkered with November 25, 2004 - R. A. Booty Return to Bob's Audio Index.