HELP!! Pace 2500-S5 sound quality problem!



My Satellite Setup
pace 2500S5
My Location

I just joined this site today as I need advice.

I know very little about satellite systems and am hoping somebody can help.

I have a surround sound system connected to an oldish Pace 2500-S5 receiver and DVD player.

I have noticed that all CDs and DVDs played through my av system sound clear and sharp, and surround sound is good.

Tv programmes and sky radio channels seem to lack that clarity and detail. The sound is good, but nothing compared to the cd or dvd, and I seem to get some surround sound but it is not like on a DVD.

I can only assume that my receiver can't handle digital cd-like sound quality.

I don't want Sky Plus or anything like that, but can somebody tell me if the above receiver being as old as it is is lacking in the right technology?

If so, can somebody tell me what to buy.

Also, am I right in thinking that tv programmes should work in surround sound, for example The Simpsons on Sky one?

Thanks in advance.