EMULATION OF NOT-LINEAR, TIME-VARIANT DEVICES BY THE CONVOLUTION TECHNIQUE

In recent years, the convolution technique has been used (and abused) for emulating the reverberation of acoustical spaces and the functionality of hardware devices (loudspeakers, microphones, preamps, etc.). Now it is also being employed for attempting the emulation of strongly not linear and not time-invariant components, such as compressors, limiters, level maximizers, dynamic processors, automatic gain controllers. As the results obtained by purely linear convolution for emulating the behaviour of not-linear devices revealed to be completely unsatisfactory, two methods for obtaining not-linear convolution were pioneered by the authors: Impulse Response switching [1,2] and diagonal Volterra multiple convolution [3]. This paper describes these techniques, and provides an evaluation of their performances both in case of memoryless notlinear devices and in case of devices which show significant memory effects