Hi

I am not an expert, but I have noticed that many hifi friends do not understand the use of DSP in hifi set-ups, so here is my view and (simple) explanation of how it is used and why.
Have fun!
Using DSP unit as a pre-amp with crossover and frequency correction.
Source is digital, like CD, Squeezebox etc.
Files are Wave or Flac, so no compression.
The source in connected to the DSP unit by coax or optical cable, the digital signal is digitally processed, can be split in, for example, stereo 3 way, low, mid, high, and can be changed in output in many ways, after that is goes to the DAC (s) to make it an analog output, that , when volume control is in the DSP, goes to the poweramps, with stereo 3 way active, at least six of them that each feed one ls unit in the speaker.
There are different types of DSP units, some with volume control (analog) like the Najda DSP and some without, like the Behringer DCX2496, that needs an external multiple volume control, most Behringer used in hifi set-ups are modified for better sound quality.
The advantage is far greater flexibility in setting up the speaker system, very elaborate room correction possible, no passive components for the speakers, when 2 or 3 way, less intermodulation when using steep cross over settings, with other words music can be played louder without distortion problems compared to the same speaker set-up with passive components.
Because all the fiddling is done in the digital domain, there is no extra hiss or other distortion in the output, when correctly set.
Big disadvantage is the need for many poweramps (the wife!) and the costs of the used DSP with or without mods.

Regards, Tom.