the Tech 21 site recommends using it with other SansAmp products.
from the site
This single space rackmount model was adapted from our SansAmp Acoustic DI pedal, with the addition of a Drive control, and redesigned as an expanded multi-instrument tool. With a sweepable, semi-parametric EQ and variable gain, the SansAmp RPM is a supercharged tone shaper for any signal source.
So maybe you play your gtr and bass thru it.
maybe you runs vocals thru it
maybe you run drums thru it
I think you could get your whole studio, intern included, in that thing.
I still have the original SansAmp Rackmount in my rack, I'm pretty sure I've used it on
every instrument at one time or another.
Seems like you'd need to play with one for a while to see if it had any mojo fror you.