On Tue, 12 Feb 2013 18:35:04 +0000, Dick Pierce wrote:
Edmund wrote:
On Tue, 12 Feb 2013 14:50:01 +0000, Andrew Haley wrote:
Edmund wrote:
I don't know if you are wrong but there are at least other claims.
http://www.channld.com/vinylanalysis1.html
I don't dispute that spectrogram, but I do doubt that it's an accurate
copy of the master tape. What's to say that the upper harmonics aren't
distortion in the vinyl replay chain? It's hard to know without the
original master tape, but I'd lay a small wager on it.
I don't know either and I could not find more info on the internet
about what is or was possible with recording in the whole chain.
Examining the spectrogram reveals little in terms of a definite
diagnosis: the extended information is clearly harmonically related to
the below 20 kHz signal, so it could just as likely be due to simple
non-linearity in either the recording or playback process. Phone
cartridges, for example, are far from the perfect linear devices we
might like to think of them as.
Some people say there is vinyl with 35 and even 50 kHz on it.
I can say with some certainty that there IS information at those
frequencies on almost every LP I have ever examined,
and I can say with equal cerainty that those signals have little if
anything to do with the original signal AND they were very likely NOT
present when fed to the cutter head.
They consist of noise, distortion artifacts and the like.
Do you know if there are records with real music recorded in high(er)
frequencies to what frequency and is there is such information somewhere
to be found on the internet?
What about the half speed cut records?
What is true or not I don't know but I do know that even today I have a
hard time finding even a mic that is able to record those frequencies.
Yup, that's right. But ANY nonlinearity ANYWHERE in the chain is going
to produce high-frequency artifacts,
that might SEEM to be correlated with the signal, but are, in fact,
added by the reproduction chain and NOT present in the original suignal.
As for the journalist, although it is philosophic more then anything
he is right about the "infinite" ( not really ) amount of information
on the analog recording and he is completely right that any
information lost by the AD conversion is lost forever.
In what sense can he be right? The amount of information isn't
infinite or virtually infinite.
I know the information isn't infinite, it just hasn't the hard limit
that a digital master has given an certain sample rate.
You are mistaking simple "bandwidth" with information. You are ignoring,
it seems, the role of dynamic range. You are also,
it seems, assuming that all information is useful. Noise is information,
but it's arguably not useful in and of itself.
With a "perfect" analog recording -that doesn't exist either I know
that too- there is no such hard limit.
The limit is an awful lot harder than you, and at least one other
poster, might think. Yes, there might be ONE part of the change that has
maybe has a 6 dB or 12 dB/octave rolloff, but you have to account for
them all. And when you do, the "ugly" Nyquist limiting looks very nice
and neat by comparison.
Consider the typical microphone, which has a series of complex
resonances and cancellations and the like. Now consider the mic preamps
and the electronics associated with that. Next,
let's look at the tape recorder, for which the definition for the
equalization curves beyond 15-20 kHz doesn't exist,
now, look at the phenomenon of head cancellation as the wavelength
approaches the dimensions of the gap, and self- erasure and a similar
set of issues on playback, and the forced limitation of the bandwidth
being fed to the cutter head to prevent its self-immolation and the
physical, limits of the cutting stylus itself, and on and on and on and
on.
Please, the effective "analog rolloff" is not some simple, nice 6- or
12-dB/octave, it's MUCH greater than that and VERY messy.
I appreciate what you are saying, really but I wonder how and why some
analog recordings sound so good...
Edmund