Date:         Fri, 1 Feb 2008 19:10:47 -0500
Reply-To:     Association for Recorded Sound Discussion List
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Sender:       Association for Recorded Sound Discussion List
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From:         "Richard L. Hess" <[log in to unmask]>
Subject:      Re: Digital File Specs and StoryCorps
Comments: To: Jon Noring <[log in to unmask]>
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At 06:03 PM 2008-02-01, Jon Noring wrote:
>Richard asked:
>
> > Please tell me again why some archives insist on digitizing oral
> > history cassettes at 96 ks/s, 24 bit, when they were recorded in
> > lower quality than this rig is capable of?
>
>There is a difference between "born digital" and "born analog".
>
>For digitizing cassettes and other analog sources, 96/24 seem
>reasonable to get a good reproduction of the background noise
>characteristic of all analog recordings. I believe having this
>information may aid any future attempts at restoration.

I think here is where we disagree. I completely agree that discs 
should be digitized at 96/24 and stereo to capture the noise 
footprint which has bandwidth out that far.

On the other hand, higher-level cassette machines than were generally 
used for oral histories are spec'd record-play +/- 6 dB at 12.5 kHz. 
If my Nakamichi Dragons are pulling anything off the cassette tapes > 
20 kHz (which is doubtful even with Dragons) it is noise--and it's 
not high enough to be bias. Since there is no useful information 
coming out of the RCA jacks of the Dragon > 20 kHz, I don't see the 
need to digitize the white noise of the playback preamp.

In discs, there are sharp transients with important components > 20 
kHz while in tape, gap loss, thickness loss, and spacing loss all 
conspire to limit the bandwidth and there is nothing useful > 20 kHz. 
Anything out there is pure white noise, mostly generated in the 
playback deck's electronics.

I don't think that's a great enough justification to double the 
storage for "just in case". I'd much rather preserve stereo 
reproductions of cassettes (since there are no good mono players) than 96 kHz.

In fact, there might be arguments more in favor of "born digital" 
recordings being wider bandwidth if  you wish to remove ambient 
noises like door slams and other things, as the mics to some extent 
and the mixer (at least at StoryCorps) can pass > 20 kHz  (mixer -1 
dB at 50 kHz).

I just don't see the ROI on digitizing poorly recorded oral histories 
at > 44.1 (or 48 depending on what you want to standardize on). In 
fact IASA TC-04 does not demand 96/24 but says something to the 
effect that some recordings may benefit from higher sample rates.

Because I'm paying for storage and the end result is a CD, I'm 
recording some community projects all at 44.1/24 (stereo or 
multitrack) and I've done some experiments at 96/24 and don't find 
the improvement. I'm using a pair of DPA 4006 TLs and a Sound Devices 
722 for this...and/or a MOTU 828 MKII.

>But if born digital, I'd keep it at the same sampling at whatever it
>was born at.

Of course!

>Audiophile grade recording of music should be
>captured at 96/24 or similar. imho of course...

Even non-Audiophile music should be captured at 96/24


> > I'm glad to see some sanity here!
>
>LOL. People have said I am crazy, so not sure on that...

I have a friend who replies to "How are you?" with "Crazy, thank you!"

Cheers,

Richard


Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.