Vinyl Asylum

RE: Why are CDs digitized from master tapes?

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This Post Has Been Edited by the Author

In Reply to: RE: Why are CDs digitized from master tapes? posted by magiccarpetride on March 19, 2017 at 10:22:19

One of the most significant differences between CD (or FM, or streaming, or ...) and LP playback is the cartridge generates the AC signal used as the source of the performance directly.
Everything else uses a power supply which is then modulated to form the source of the performance. Thus, everything except a phono cartridge (or many types of microphone) is dependent on the power supply for it's sonic qualities, and there are not many people who would argue that power supply quality isn't relevant. Nor is it cheap, so it's often a target of compromises.
If you are cutting a CD master from magnetic tape (which is the old way, although some producers and engineers still use it today) alongside a concurrent master for vinyl, you have no choice but to experience the high 3rd Harmonic Distortion that is inherent in the magnetic tape format*. So it's not a matter of lower distortion on the CD.
* The term "THD" was first applied in the early 1950's as a measure of the distortion characteristic of open reel tape decks, and meant at the time, "Third Harmonic Distortion".
3HD on a tape machine will begin to rise and is typically in the whole percentage range at levels above -20dB (say, up to 3%) and could rise to as much as 10% at +3~+8 Vu. People who listen to old recordings are familiar of the sound of tape saturation on vocal peaks as singers, recorded live, moved too close to the mike.
Similarly, as an effect, the acoustic guitar and snare on the Rolling Stones "Beggars Banquet" album (1968) were recorded into a cassette deck to generate high 3rd order distortion effects. And the cassette decks of 1968 were considered suitable only for dictation. They were far from the HiFi decks of the mid to late 70's.

Edits: 03/27/17 03/27/17 03/27/17

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