D/A -> A/D How Bad?

J

jeffoest

New member
I've always tried to maintain as much digital in my signal chain as possible but it's not always the easiest thing to do.

For example - I record my vocals on my Akai DPS16 hard disk recorder in 24-bit. Then I run it to an outboard analog compresser (RNC) (D->A) though a digital effects unit (A->D) which goes digitally back into my hard disk recorder.

So my first question is - how bad is this? I don't really think I can hear the difference but then others may and I may not know it. Am I degrading my 'chain' horribly - am I an idiot to daring to leave the digital realm? lol Supposedly the A/D converters on the Akai DPS16 and the TC Electronics M-OneXL are 24-bit and decent but I don't know...

Next question on A/D D/A conversion. Because of the technology of the Akai DPS16 (which I love!) there is no way for me to efficiently bring my digital data to the computer for finalizaing/some mixing/mastering/ etc... I always end up writing it to a disk (using SCSI because that's all there is) which takes a LONG time (especially for 30-minute mixed podcasts which I'm starting to do) and wastes a perfectly good CD disk.

I'm thinking about buying a portable digital device like the Edirol R-1 as a 'transfer' unit to my computer. Unfortunatley the Edirol has no digital input so again I would have to record the mix from the Akai in real time to the Edirol using the Edirol's A/D converter. From there I'd be in 24-bit digital the rest of the way. Question is - am I being dumb for considering this? Or is it a reasonable idea to save me some time. How do you judge the quality of a a/d d/a converter? Is there a better digital storage device that can accept digital in/outs?

As an extensionor worst case, if you took a piece of digital audio through say 20 d/a->a/d conversions - how bad would it be?

Thanks all!

Jeff
 
jeffoest said:
As an extensionor worst case, if you took a piece of digital audio through say 20 d/a->a/d conversions - how bad would it be?
Click to expand...

Run a series of test tones, every octave from 1kHz up (2,4,8,16) through the whole chain and see what it looks like.
 
Interesting thread - thanks for finding that for me.

So it sounds like if the converters are good, then a generation or two won't make any real practicle difference (at least that's what I get out of it). Now - how do I know if my converters are any good? They are all "24-bit" if that makes any difference but I suspect there is more to it than that. ;-)

But given the D/A converters I would go through are all parts of other equipment (i.e. not the main 'event') and all pretty much consumer-grade type stuff, my guess is that the converters are crappy at worst and average at best. Which means my question remains alive! lol Can it sustain a couple of generations of conversion?
 
Out of curiousity, can you hear a difference? I've never played with all the conversions like that, so just wondering if you can tell by listening, or is it subtle.
 
I don't know if I can hear any difference when I have been using the outboard compressor but then again I don't have anything to A/B with - I can't go to the outboard analog compresser digitally... so it's a conundrum. Also, I don't think I have the subtlest ears so I'm not sure what I hear makes as much difference....
 
To test just the convertors, just patch an output on you interface back into a line in and record. Repeat as many times as it takes for you to notice a difference.
 
In a/b'ing the same source, mic's and pre's, using my Lucid vs. RME Digi96 converters I can hear a big difference just in the A/D. If I ever pick up a Lucid D/A, I might consider going through extra conversions for processing, but definately not with anything less. And the Lucid is a good but just mid-level converter. Haven't had the pleasure of a/b'ing with a Prism, Lavry, or the like.

The difference I hear is similar to the difference between my Great River and Mackie pre's. The low end is richer without being boomy or woofy, highs are sweet and clear without hard edged transients or a grainy veil, mids are more detailed.

Just my 2c,
Tim
 
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