Is it possible to run a sub and amp off of a standard RCD510 and what cc is the box, has it been designed to work with a specific speaker brand?
You have to run a line out converted from an rcd510 (i have an rcd510 DAB myself so I know it works)
The cheap way is to get a £15 LOC and tap the rear speakers and run a sub from there. Then you can adjust sub level by adjusting front / rear fade.
The expensive way (which i've just done) is with something like an Audiocontrol LC2i. This give a strong clean pre out for front speakers and also a bass output. You can also run a bass control remote dial off this unit.
This is then feeding my JL HD600/4 amp which in turn is running front components and a sub in the rear.