Does HK include DSP?

I guess I'm not too smart, but I'm not sure if I have DSP or not. I just bought a 2001 325i with the HK premium sound. Does that include the DSP or not?

I'm wondering because I need to know what kind of cd-changer I can purchase. Anybody have any good suggestions for a cd-changer while I'm on the subject?

Thanks!

dsp is standard,hk sound is not related