I've used FLAC for years to make copies of my CDs. Being a little leary about reducing the size of the original, I also did extensive testing and found absolutely no difference at the bit level. Most of my FLACs are image copies of the entire CD including gaps, etc.

There should not be an audible difference between a FLAC copy and the original no matter how good the audio system. If there is, it is probably the FLAC decoder. I've never heard of such a problem, but if that is the case, find another decoder. The FLAC site is here.

R