Bren, I assume that Tom is talking about a connection from his CD player just a few feet long. Using the 44.1KHz sampling rate and applying the common 128 times sampling rate suggestion for flawless digital transmission, we get about 5.6MHz. For wavelength take speed of sound (300,000,000 m/sec) divided by 5.6 MHz to get a little over 50 meters. Using the common standard of characteristic impedance of an interconnect being significant when it's longer than about 1/4 wavelength, we get maybe 12 meters or 40 feet before characteristic impedance of a CD interconnect needs to be taken into account.
