DSP! DSP?

[ukrcan]

So I was reading about may car's stereo today and in the manual it says - you have a DSP enabled radio and you can change the sound by selecting different modes...
I have tried selecting one of the three pre-set modes - Concert Hall, Jazzclub or Church but i did not hear any difference in sound. I also tried setting my own settings - same result. Tried both FM Radio and CD... am i doing something wrong? or is DSP busted?
Now, i do have an aftermarket Satellite Radio unit installed in the car ( A gift from the previous owner i guess) but it works over FM, so i don't think it should interfere with the DSP module, or should it?
Would be nice to be able to use the radio with its full potential...