Some of the answers above aren't exactly true. Most CD-r burners don't make perfect bit for bit copies and can introduce errors as multiple generations are produced. This is in part due to the large amount of data involved with digital audio. The only way I've seen to make true bit for bit exact audio copies of CD's is to use a PC (or MAc) with software that does DAE (digital audio extraction) from the CD and then reburns that data onto the CD-r. Exact Audio Copy is company that makes the only software that I'm familar with that checks the extracted audio bit for bit with the original to make sure the copy is exact.
