Compressibility can also be of importance in acoustic problems.
The acoustic velocity, or wave speed is directly related to the bulk modulus and compressibility. If acoustic resonance occurs in the ductwork the acoustic velocity must be known to effect a successful cure. Acoustic resonance can be a very serious problem creating destructive ducting vibrations and large pressure pulsations. The acoustic velocity calculated from the bulk modulus applies to pure clean gas. If the gas has solid particles, the acoustic velocity will be greatly reduced from the theoretical value. Testing may be the only approach to find the true value.
Posted in Fans Ventilation A Practical Guide