Convention Paper
Nonlinear Versus Parametric Effects in Compression Drivers
AES Convention 115 · Paper 5912 · October 2003
Abstract
The compression driver has always been and remains an essential component of sound reinforcement systems despite its unavoidable nonlinear distortion. This distortion is caused by various effects, including adiabatic compression of air in the front chamber, modulation of the chamber's air stiffness, and modulation of the chamber's viscous losses. Each of these sources of distortion is inherent in the compression driver's operation, each adversely affects the compression driver's performance in its own specific way, and each is characterized by a different nonlinear 'signature.' Comparative analysis of these distortion sources is undertaken. Nonlinear and parametric effects are explicitly expressed. The influence of diaphragm displacement, compression ratio, and chamber sound pressure on the generation of intermodulation and harmonic distortion is explored. Some design recommendations are given.
