|
|
Posted by Mike Rivers on 04/21/06 15:07
Romeo Rondeau wrote:
> Trying to apply analog tape salvaging techniques to digital
> media (or sometimes no technique at all) and then complaining about how it
> doesn't work well isn't getting anybody anywhere. Damaged CD's and DVD's can
> be salvaged (some of the material will not be usable, just like analog
> tape... no difference there.) Putting the CD in the drive, then throwing
> your hands up and exclaming that digital storage cannot be salvaged when
> there is a problem is a bit like throwing the car away when a tire goes
> flat. There are plenty of tools out there to recover as much of the digital
> file as possible. That's the best you can do on analog as well. It's a lot
> easier to fix a dropout on a DAW than it is to fix it on analog tape.
Not necessarily easier, but you have more possibilities. WIth analog,
your choices are pretty much limited to ignoring it or editing, both of
which are done. But with digital tools (even when the source is a
digital copy of an analog recording) you have a lot more ways of making
the edit undectable to anyone who isn't specifically listening for it.
But one problem is in the way that things fail. Analog tape has
basically three failure modes:
(1) Dropouts - Unless a large length of tape has been physically
damaged, these are usually brief and sporadic, and can usually be fixed
through editing if you care
(2) Loss of high frequency response - Partial erasure can occur from
playing or storage, but it's generally uniform throughout the tape.
Crank up the high end, apply some hiss reduction, and you're good.
(3) Physical damage - splices and breaks can be repaired almost
perfectly, sometimes better than new. Stretches are tough, but digital
time/speed adjustments can fix them. We don't really count sticky shed
and loss of lubrication, because first you have to be able to move the
tape, and with the right technique, you can solve this problem, then
see what other problems you have.
Analog tapes don't build up crackles and pops with age like us old guys
do, and their distortion and background noise levels (other than from
magnetization) don't increase. All of the problems are mechanical in
nature.
Digital is a little different. There's really only one failure mode,
and that's loss of more data than your error correction system can
handle. While the change of one bit, if not caught, might cost your
bank millions of dollars, nobody's going to complain about the loss of
a single sample. In order for it to be a problem with audio, you need a
long string of sequential failures. That can be a result of media
failure. If it's something you can edit around, no problem. But if you
have enough errors so that you have continuous crackling or muting,
that's something that doesn't have a parallel to analog problems, and
you have to fix the source (what the data is read from) in order to fix
the problem.
There are standard and devilishly clever data recovery techniques.
Sometimes they work, sometimes the don't, and sometimes you can recover
some, but not all, of the project. You have more apporaches with
digital, which means you have more chances of performing a miracle, but
you also have more opportunities where you NEED to perform that
miracle.
But basically youre right on - shit happens, you fix what you can, and
you move on. Maybe someone a generation later can do more. One
advantage of digital is that you can always clone it in whatever state
it's in, so for as long as you want to keep fooling with it, it won't
deteriorate further, which analog media will almost certainly do,
eventually.
> Point is, if
> you throw the CD in the drive and it doesn't read, find out why, then fix
> it... if you can't fix it, get as much as you can salvage and try to make it
> inaudible (easier than you think), if you can do it, hire it out to someone
> that can. Anything less is unprofessional at best.
And, true, level of professionalism is important. Most "ordinary"
people like me don't really know much to do in order to fix a CD, and
most of us don't feel sufficiently committed to hire a professional to
give it a try (no guarantees from any of them either), but it's
certainly easy to whine about it. Thing with a CD is that there are
certain forms of damage that will keep any of it from playing until you
try to extract the data and make a new CD. With analog tape, you might
cringe because you know that quarter-note dropout in the middle of your
favorite trumpet solo on the tape is coming and there isn't a darn
thing that can be done about it since he never played that note again,
but at least you can enjoy the rest of the tape.
So which is superior? Whatever.
Navigation:
[Reply to this message]
|