the zapco is a full digital signal processor:
Zapco - Processors
it is 6 channel in 6 channel out, computer controlled with GUI
you have individual controls of 10 band parametric crossover with 1 hz steps
hi/low/bandpass filters with two types of filter and 6 to 24 db/octave slopes
time alignment
input and output gain adjustment
this is on EVERY channel.
think of it this way.
say instead of car audio with high sound quality as the goal
lets say you are building a custom engine for maximum performance.
the DSP would be like a high end stand alone engine management system...that allows you fine tune everything to obtain the best results.
the DSP does the same, except for listening pleasure
b