Using Nonlinear Amplifier Simulation in Dynamic Range Controllers

Amplifying devices where the gain is automatically controlled by the level of the input signal performs dynamics processing. Non-linear components simulating tube amplifiers can be used in these devices to make musical signal audibly dense [1]. This paper deals with the simulation of tube amplifiers using the power polynomial approximation of transfer characteristic and their use in dynamic range controllers. The influence of various non-linear amplifying devices simulating tube amplifiers on the output signal spectrum of dynamic effects is presented as well. A non-linear amplifier placed after the dynamic effect makes no sense with the dynamic range controller. In addition to this it can increase level of the dynamic controller output signal and degrade the limiter and/or compressor operation. A non-linear amplifier placed before or after the delay block causes that the level measurement block follows envelope of signal that differs from signal entering the multiplier to weight the input signal. Fig. 2 shows static transfer characteristic of the envelope follower without any non-linear processing (dash line) and with a non-linear amplifier with transfer characteristic according to Fig. 4 placed before the delay block (solid line).