It has been almost twenty years since Sony first advertised the brand new audio compact disc with the slogan, "Perfect Sound Forever." That slogan signified the beliefs, then widespread in the commercial recording industry, that 1) the newly adopted Redbook compact disk standard, with recordings encoded with 16 bits, sampled over 44,000 times per second, was de facto perfect, i.e. when properly done was indistinguishable from the live sound, that 2)· older analog recordings (on tape) being less than perfect could be simply transferred to digital in sonically transparent recordings, and 3) that since the process of encoding was done digitally, digital copies, including those typical of making commercial discs from the master tape were absolutely identical in sound to the originals.