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Re: 2 Q's: Digital dropouts & low con prints

Lon writes:

> johnmcd at one.net writes:
>> and irreparable audio dropouts (couldn't layback the audio after multiple
>> attempts). This was on the first playback after recording the transfer. Can
>> these dropouts be detected during the transfer process at the lab facility
>> via some confidence mode (automated even?) before shipping?
> My experience is that usually what passes as digital audio dropouts
> actually turn out to be uncorrected errors.  A true dropout would usually be
> covered by error correction.  But an uncorrectable error will often invoke a
> momentary mute.  This can be perceived as a dropout.


The terminology is used unclearly (at least by me). I guess that you could
say that a dropout is a "detectable" error, ie: a muting of the audio or a
audible degradation that is beyond correction by the error correcting
algorithm. OTOH, a correction is correcting something and that something
would be a media failure; aka: a dropout. The problem with error correcting
media is deciding on what constitutes an acceptable correction. Some
"corrected" errors on DAT can be perceived as stereo image shifts, apparent
volume drops or very momentary degradations of one or both channels. More
noticeable are those that sound like extremely short bursts of static.
Depending upon the program material, these may not be very noticeable. I've
sat in the studio with people who didn't notice them at all while they were
driving me up the wall (I have a pet peeve about tiny ticks and pops).

On the DigiBeta in question, repeated attempts to perform an audio insert
resulted in audio dropouts in the  same place. The tape was toast.

Regards, John McDaniel

Thanks to Philips for support in 1999
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