[Ardour-Users] Experience? Rework an external 44.1 KHz 16 bit recording

[Ralf Mardorf]

On Thu, 2010-08-19 at 09:45 -0700, Mark Knecht wrote:
> On Thu, Aug 19, 2010 at 9:18 AM, Ralf Mardorf
> <ralf.mardorf at alice-dsl.net> wrote:
> > On Thu, 2010-08-19 at 11:54 -0400, Paul Davis wrote:
> >> On Thu, Aug 19, 2010 at 11:38 AM, Ralf Mardorf
> >> <ralf.mardorf at alice-dsl.net> wrote:
> >>
> >> > A million years ago I copied using coaxial S/PDIF, but it wasn't a 75
> >> > ohm cable, from my AIWA HD-S1 DAT to my Sony DTC-670 DAT and there was
> >> > loss, not dramatic, but audible. I don't have coaxial usable for my
> >> > sound cards, hence I would need to use a 2 m or 6 m optical waveguide.
> >> > S/PDIF indeed seems to have loss.
> >>
> >> digital signal transmission isn't "lossy". it either works or it
> >> fails. that's the whole point.
> >
> > Okay.
> >
> > Is 'lossy' just the wrong word? I 'guess' I did hear loss when doing a
> > copy from DAT to DAT, using an audio cable, but a 75 ohm cable. I read
> > about this as a common issue for optical waveguide in the audiophile
> > mags at my dentist :D, but they do write a lot of nonsense. I always
> > wondered why there seems to be loss when doing the S/PDIF copy from DAT
> > to DAT, but at the same time DAT also is used to backup computer data. I
> > guess for the computer it's not called DAT, but they use the same tapes
> > and mechanics.
> >
> > Anyway, you explained why ripping the CD might be more safe, than using
> > S/PDIF. Let's they at least for CD the fail would cause loss ;).
> >
> > Btw. thank you for the CD explanation,
> > Ralf
> 
> If you used an audio cable to copy, you weren't really copying. You
> were doing playback and record. That will be lossy.

I was using an audio cable for S/PDIF. It was a short cable and product
contents as S/PDIF cable for my AIWA DAT recorder. S/PDIF should be 75
ohm while audio cables might not be 75 ohm.

> You can put digital data on tape, and as Paul and others have said, if
> you make a digital copy then it's lossless. It either works or it
> doesn't. If you playback an audio recording held on DAT then that
> digital data is turned into analog, and at the other DAT it's turned
> back into digital. That always works but is lossy.

No, I was talking about issues with S/PDIF. That's why I asked and
several people would prefer at least for the CD to rip the data, but to
use S/PDIF. The 'bad block' issue might be for CD only, but perhaps
there's something similar for DAT. 

> I'm assuming here that we're talking about an ADAT interface. If I'm
> wrong about that assumption let me know. As far as I know ADAT
> interfaces come in two or possibly 3 varieties:
> 
> 1) Some sort of older style parallel wire cable. I don't own any of
> this sort of equipment.
> 2) A laser interface to optical cable, which is what I use. (Glows red, right?_

That's what I've got now for S/PDIF, but never used it.

> 3) Probably a spdif output.

S/PDIF could use optical waveguide or coaxial 75 ohm with any kind of
jack, not only cinch (or BNC), but also mini stereo jacks as my AIWA DAT
has got.

> All 3 are digital only TTBOMK.

Correct!

> The DAT machine may also have built in
> D/A and A/D. If you use those you get analog with all of it's inherent
> beauty and faults.
> 
> - Mark

Anyway, I even will start ripping the CD now.