It depends on how you handle your audio. If you send it to the receiver from the DVD or CD player via a digital input (coaxial or optical) then yes, it only really matters how good the DAC's (digital-analog converters) are in the receiver. That's because the receiver will receive the media digitally, convert it to analog, and then output it to the speakers.

However...if you have a high quality CD or DVD player with better DAC's than your receiver and you pass along the signal to the receiver via analog cables (RCA), the receiver would basically act as a passthrough and send your audio signal untouched to the speakers.

This is my understanding, and I believe it to be correct. If you still don't get it, perhaps someone else will be able to explain it more clearly or I'd be happy to try again. Either that or I'm wrong and someone will tell us that too!

My M60's make me listen
My M80's make my ears hear
Either way - I'm not deaf anymore