Re: Copying minidiscs

[Tom Ritchford <tom@swirly.com>]

"Michael S. Yoder" <myoder@tamiu.edu> wrote:

>Saludos de la frontera!
>
>I have a question for those of you with experience in MD recording:
>
>Is it ABSOLUTELY crucial when making backup copies of MDs to record them
>digitally via the optical output and input?  Is there noticeable audible
>difference by going through the line outs of one MD machine into the line
>ins of another MD machine?
>
>I have experience with DATs, and can hear no difference between an 
>original
>DAT and the copy made via the line outs and line ins.  This must mean that
>the D/A and A/D converters are good in the Sony DAT machines I use.  I
>wondered if the (much cheaper) MD technology would be about the same.  One
>can get a Sony MD deck for just under $200, but without optical output.

This is an interesting question.

MDs perform their magic using a "lossy" compression that throws away
most of the raw sonic information received to compress the bandwidth
and fit all that sound onto that little disk.

The ATRAC encoding is very sophisticated and uses multiple
strategies to make sure that most of the information lost
is information that you could never possibly hear.

But information is lost on each encoding->decoding step.
This will snowball and after several generations, you'll
start to hear artefacts.  So I'd reckon, I've never tried
it, but this is universal to lossy compression methods.

Note that this will happen whether or not you go through
an analog stage.  And, as Michael says, a careful and
accurate analog copy is pretty indistinguishably close
to the original.


BUT, I'd still go with the digital I/O if you have
another device that reads it.  It's just far simpler
to make an exact digital copy than an exact analog copy.

Setting your levels wrong is a classic way to lose
bandwidth on a copy, not a problem with digital.

Crosstalk or hum from other channels or instruments,
static electricity, these are all things that have
ruined analog copies of mine in the past.

With digital, you plug them in and press record.
End of story.  No work.


This is terribly off-topic of course.