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Re: MD Technology review

Subject: Re: MD Technology review
From: Dan Dugan <>
Date: Mon, 8 Jul 2002 15:58:56 -0700
Walter Knapp, you wrote,

>What you are also saying is that a DAT recorded original transferred to
>CD is changed by the process. I would agree, everything we do changes
>the signal some. Even simple digital transfers are not 100% accurate.
>That's why there are error correction routines in the software.

Not so. Simple digital transfers (like CD or DAT into DAW, or 
vice-versa) are normally perfect, that is, bit-for-bit identical 
files are produced. When a DAT tape or CD is being played, it's 
normal for error correction to reconstruct data that can't be read. 
But that correction results in just that--correction of the read 
errors, and the output of the player is the original data unless 
gross errors bring the process up past the threshold of correction 
into the region of error concealment.

and further on,

>I realize there is this belief that something must have changed and if
>we listen just the right way, we will hear it and find out just which
>samples it threw out and which it kept. I, too know something had to
>have changed, the ATRAC threw out 100% of the original data (not some
>samples only), generated new data that described the original but took
>up 1/5 the storage space, and then used the new data to generate a
>reproduction of the original. One that's good enough we can't hear the
>difference, and neither can the animals we deal with. I do not expect to
>hear the differences, no matter what technique I apply. I do know I can
>find small differences by sonogram. I have come to these conclusions as
>a result of many years of recording with ATRAC encoding. I did not start
>out believing I would hear no difference.

An excellent, fresh description of the encoding process. One must 
also consider how much damage analog recording does to an audio 
signal!

-Dan Dugan


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