wrote in message ...
On Oct 22, 3:35�pm, "Serge Auckland"
wrote:
In addition to all the above, don't forget that all pick-up cartridge
have
harmonic distortions of the order of 2-3%, some higher, some perhaps a
little lower. Considering that an analogue tape machine will also have 3%
distortion (that's how peak level is defined, the 3% distortion point)
and I
have no idea how much distortion the cutter itself has, plus springback
on
the lacquer which leads to harmonic distortion, the total is
considerable.
That's another form of inherent coloration.
S.
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A valid point. But how much of that harmonic distortion is audible?
It's hard to say as it depends on many factors. However, tests done on
harmonic distortion that I recall reading many years ago indicated that 1%
was the lower limit for audibility, but it depended on frequency and masking
by other sounds. As I recall, that was the origin of the 0.1% distortion
desiderata for amplifiers as it was 10x better than was likely to be
audible, and could therefore be comfortably taken as being completely
inaudible under all circumstances. Nothing in the intervening 50 years or so
has made this invalid as far as I know.
As to vinyl, I suppose one could cut a record from an unequalised digital
master and similarly produce a CD and compare the two. However, the limited
dynamic range that would result from having necessarily to cut from an
unequalised master would not be a valid comparison with "real world" LPs.
Practical LPs are cut from masters specially equalised and compressed to get
the best subjective result from the limited medium. There is also a great
deal of skill (art rather than science) on the part of the Cutting Engineer
who will try and balance the conflicting requirements of noise against
level, frequency response against level against distortion, level against
playing time and pre-echo, level against playability by less sophisticated
record players, managing stereo difference i.e stylus vertical movement, and
possibly other things I haven't thought of.
Can you imaging someone starting out today, with no knowledge of vinyl, and
trying to invent a mechanical engraving system to reproduce Hi-Fi sound? I
think anyone would conclude it's just not possible, and yet......
S.
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