DUBBING or DUB
A general term referring to the copying or transferring of audio material. Each time an analog copy (dub) is made, some quality is lost.
When an original source has been copied (i.e. dubbed) once, this copy is known as a first generation copy. A copy made from this first copy is called a second generation copy. With each successive generation, the quality of the original sound is reduced and the BACKGROUND NOISE is increased. This problem occurs only with analog audio signals, as stored on MAGNETIC TAPE, for instance, and not at all in DIGITAL RECORDING as long as the copy is error-free.
See: HISS, PRESENCE, SIGNAL-TO-NOISE RATIO. Compare: MIXING, SOUND-ON-SOUND.