With perfectionist audio, a perfect digital chain is often described as “bit-perfect”. When two player applications are both bit-perfect; there should be no audible difference between them (when the rest of the chain remains unchanged of course). People now realize this is wrong; they hear differences between players such as Amarra, Decibel and Itunes. Actually this observation is not heavily discussed; most people can hear it. So clearly bit-perfect alone is not enough to describe the quality of a digital audio player. When describing a DAC; bit-perfect is not a point of discussion, however another parameter called ‘jitter’ is (check wiki for background on jitter).