Re: arsclist ["David Satz" <DSatz@msn.com>]

[David Ackerman <dackerm@xxxxxxxxxxxxxxx>]

David,

I appreciate your comments.  I'm starting to feel like I am playing a game
of telephone with this stuff, so I am going to make one last attempt to
clarify my view. Responding to a post I read on Sound-L I sent out a list
of characteristics I would consider when assembling a system for
digitizing TAPE recordings (reels and cassettes if memory serves).
Although I am not certain in that persons case, it strikes me that the
potential exists with the format for a wide dynamic range. Also somehow I
managed to read Steve's comment to be an issue of level and not dynamic
range. When I went back and looked this morning it was clear that I was in
error.  I appologise to the list for not reading more carefully. And
lastly, I was simply echoing Steve's assertion that it seems more straight
forward to convert from 88.2 to 44.1k.  I'm still not sure what his point
was.  Perhaps it was just a reaction to my earlier stating it as one of
many possible sample rates? 

Oh and I agree with you that proper dither is the key to eliminating
quantize distortion. I believe I even said so in my original post, though
perhaps not as clearly as I should. Of course not all systems
automatically implement dither.  In fact often it is the better
workstations that leave when to dither and what kind of dither to use in
the hands of the engineer. So in some situations care must still be taken
to avoid the distortion you mention.

Best regards,

Dave


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On Mon, 19 Feb 2001, Esther Gillie wrote:



> This is a fairly common misunderstanding.  I don't think it's the
> purpose of this list to argue technical details, so as a broad but
> reasonably usable generalization:  given proper dither, the main
> difference between 16- and 24-bit A/D conversion will be the noise
> level of the result.  Low-level signals in a properly dithered system
> are not a special problem.  The old scare stories about low-level
> signals being turned into square waves and "digital deafness" at
> low levels are holdovers from the early 1980s, when dither was
> not always uniformly or properly employed in, for example, Sony's
> PCM 1600-series studio recording system (which was used to
> record the master tapes for many early digital recordings).
> 
> If that problem may be regarded as solved, then you need only
> make certain that the medium you're using for a transfer is 10+
> dB quieter than the source material, so that the process will not
> raise the overall noise level.  16-bit PCM fulfills that requirement
> by a very wide margin, given the source material mentioned here.
> 
> Not all 16-bit recorders have the best sound quality that can be
> achieved in 16 bits, of course.  A particular 24-bit 96 kHz system
> could very well sound better than a particular 44.1 kHz 16-bit
> system--_or vice versa_.  Those specifications, without more,
> simply aren't any guarantee of quality sound.  They can't be.
> 
> 
>  >> The only advantage to using the higher number 88.2, divisible by 2,
>  >> not 96K which either leaves more fractions when brought down to 44.1
>  >> or rules out using the cheap compact disc recorder at all, is that the
>  >> processing occurs with fewer fractional numbers before coming back
>  >> down to 44.1.
>  >
>  > I put the subject of higher sample rates on the table, while clearly
>  > indicating that this is an area of debate. Regarding 88.2 and 96k, yes
>  > the math is much cleaner to convert down to 44.1khz from 88.2khz.
> 
> The math may be somewhat simpler, but will you be implementing
> the sampling rate converter yourself?  If not, then why is the ease or
> difficulty of the algorithm your concern, rather than the result?  Both
> hardware- and software-based converters are readily available which
> can handle the conversion to 44.1 kHz without compromising sound
> quality in any particular way.
> 
> However, I think for the purposes being discussed here, a good 16-bit,
> 44.1 kHz CD-R system is far more than adequate--there is no need to
> deal with the problems of storing 24 bits or converting sample rates.
> 
> --best regards,
> 
> David Satz
> Brooklyn, NY
> Esther Gillie, Sound Recording Archivist		Phone: 716-274-1330
> Eastman Audio Archive				Fax: 716-274-1088
> Eastman School of Music,  Sibley Music Library	esth@xxxxxxxxxxxxxxxxxx
> 27 Gibbs Street, Rochester, NY 14604
>