Modulation And Delay Line Based Digital Audio Effects
Sascha Disch, Udo Zölzer · 1999
In the field of musicians and recording engineers audio effects are mainly described and indicated by their acoustical effect. Audio effects can also be categorized from a technical point of view. The main criterion is found to be the type of modulation technique used to achieve the effect. After a short introduction to the different modulation types, three more sophisticated audio effect applications are presented, namely single sideband domain vibrato (mechanical vibrato bar simulation), a rotary speaker simulation, and an enhanced pitch transposing scheme. 1. EFFECT CLASSIFICATION Many audio effects are based on mixing the original signal with delayed and/or amplified copies of it. The delay is implemented in integer multiples of the unit delay. If the delay is greater than one unit delay, the chain of unit delays is referred to as delay line. If the delay time and the corresponding coefficients are constant, the well known FIR (finite impulse response) and IIR (infinite impulse r...