Gerry, your question isn't entirely clear, but if you mean can a Blu-ray player play CDs just as well as a "dedicated" CD player can, the answer is yes. Playing CDs has reached a state of technological maturity quite a while ago and even very modestly priced players(including those that also play DVDs and Blu-rays)do so with audibly flat response and inaudibly low noise and distortion. Better than that isn't possible, despite manufacturer claims and fanciful reports of some reviewers.

Nope. It won't make any difference at all.