Re: arsclist Arhoolie foundation project.

[David Ackerman <dackerm@xxxxxxxxxxxxxxx>]

On Sun, 18 Feb 2001, Steven Smolian wrote:

> 
> 
> I thought George B-N's comments on 24 bit, which is primarily to
> increase signal to noise- in other words, level were interesting,
> considering we are trying to save so much with a dynamic range in the
> 25-45 db range.

Steve,

Perhaps I am misreading your comment, but it is my understanding that the
key difference between 24 and 16 bit is the decrease in the signal:error
ratio that comes with the higher resolution. I would think that this
characteristic of 24-bit would be most noticeable when dealing
with low level audio.

> 
> This whole thread comes out of a response from Harvard's engineer who
> seems to have infinite $$.  Many of the respondents are answering at
> the same financial level.  It's pretty impractical for most, but
> supports my point, posted to the AV and Sound-L listserves about using
> 44.1 and 16 bit for oldies.


Well, I'm glad to know I started something here ;-) To clarify my original
response, I don't believe anyone has infinite resources - but not having
heard or inspected the material the original poster plans to preserve - I
feel that they should be presented with a range of options. Starting with
an approach that will produce the highest quality re-recording and then
working down from that to a reasonable approach that they can afford.
Also, I did try to offer some sense of priority for where to spend money
when putting together a system for digitizing (i.e. that the A/D converter
and a bit tranparent system are of paramount importance).


> 
> 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.  As far as
ruling out a CD recorder [I guess  you mean in the same pass eliminating
the need to downsample], again it all comes down to what you use to get
the job done.  As I said in my last post, generally speaking you get what
you pay for.  For example the prism AD2 converter can output multiple
sample rates simultaneously. So you could record 88.2 or 96k into your
workstation or to a genex or whatever, and feed 44.1k to your stand alone
CD recorder.

> 
> With all the hundreds of small operations with the dire need to
> preserve older folk and other audio recordings, I think what we're
> looking for is "the greatest good for the greatest number," rather
> than "the greatest great for the few using the highest numbers."

Actually I thought I was responding to one persons inquiry about what
options exist for digitizing their collection. Not making policy for
anyone. As an aside on equipment cost - Is it even possible to buy a
modern DAW or converter today that does not handle 24-bits?


 ------------------------------------------------------------------
|  David Ackerman               |  Telephone: 617-495-2794         |
|  Audio Preservation Engineer  |  Fax: 617-496-4636               |
|  Archive World Music          |  e-mail: dackerm@xxxxxxxxxxxxxxx |
|  Harvard University           |                                  |
|  Cambridge, MA 02138          |  PGP key 0xE928B52F              |
 ------------------------------------------------------------------