WALT
> > Since CD audio is the same uncompressed audio, why do you not
>consider
> > it backup? It can be pulled back into the computer with no loss.
EVERT
>On some other forum or website (don't remember which one) I found out
>that although the actual sounds are not altered (compressed) there is
>one serious 'problem': the computer stores the wav file, and any
>other file for that matter, in a certain amounts of blocks.
>Typically these blocks are 4 kB (I am telling this out of my poor
>memory so the figure 4 might be wrong.)
>
>When the wav file is burned to an audio CD format the blocks files
>get another standard size, and that is why it is to my strict
>standard no longer a back-up since the original form of the data (in
>this case the blockfile size) has been changed.
>There could be mistakes which are unaudible, but after resizing
>againg from CD audio to WAV there is HUGE potential for loss of
>information.
Any digital transfer of information will involve reformatting of the
data, but I can assure you that these processes are totally
transparent to the data.
>If you ever tried to rip audio CD's with progrock - where there are
>no pauses between tracks, but the music just keeps on going, just
>like a live recording - you will often get problems at the beginning
>of each track.
>
>I fully realise that this is a problem that only occurs under certain
>circumstances that do not occur often. But still, there is an audible
>difference, so for me it is not a back up, it has become a dead-end
>user product.
The problem is with ripping, not with the CD audio format. Because
audio CDs are written in a continuous stream of CD frames instead of
physical sectors, it's very difficult to load them in at high speed.
The answer is to play them on a CD player with digital output, and
capture the digital output in a workstation. This produces
bit-perfect audio files unless the CD is grossly damaged.
>A bit off topic now:
>It is the same reason why bands do not - just copy that consumser CD
>1000 times - but use the master tape (or master optical disc).
>
>For instance a wonderful band called Iona recently re-released their
>first 4 albums, but they did not make the new release out of an
>easily available consumer CD, but instead had to go back to the
>original masters.
>
>Those masters were analog multitrack tapes.
>The tapes were so old they had to be baked again (yes: baked in a
>special oven)
I recommend the Excalibur food dehydrator, works great. The need to
bake tapes is -not- a matter of being "so old." Old tapes (e.g. 60s)
can be just fine. The problem is bad binder chemistry (adding
urethane) that was used by most manufacturers in the 70s-80s. I'm
sure you've encountered old foam rubber that's turned to goo?
Urethane, bad plastic! Seemed like a miracle substance at the time...
>then they were transferred to the computer where they
>were digitally re-pitched to concert A, because the original
>masterrecorder was a bit off pitch (machine was running slow).
>Why would a band go through all this trouble instead of just ripping
>the CD that was released a few years ago and just copy it a few
>thousand times? Because a ripped CD will not be the same as the
>original, partly because of the blockfile size matter and also due to
>possible errors during ripping: the CD could be slightly damaged and
>thus you 'copy' the mistakes too.
There are advantages in going back to the analog. Today's A/D
converters are better than those of a few years ago. Of course you
have to balance that advantage against the possibility that today's
transfer engineer might know less about analog recording, and might
not get azimuth, EQ, and levels right...
A ripped CD is likely not to be identical to the original files. A
digitally-copied CD is likely to be perfect unless the CD is badly
damaged.
>All this makes me and others state that an audio CD is not a back up.
I suggest archiving audio two ways:
1) as data CDRs of all the workstation session files including
original audio files and bounced finished track files. This enables
reloading the session when wanted for for further work, or loading
just the bounce files when you want to burn more CDs;
2) as an audio CDR, which is convenient for just listening to
something, and serves as a second archive of the bounce files if
needed.
The fly in the ointment of all CDR processes today is the changes in
the blank stock that have been made to accommodate higher speed
burning. Today's CDRs have lower modulation levels at any recording
speed, and thus are more likely to have problems with a player/reader
not in top condition.
-Dan Dugan
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