I think it's important to remember two things here.
1. We're talking about preservation.
2. the A/D converter is arguably the most important part of the chain in digital preservation.
If there are places where price point has to be a determining factor, don't make one of them the A/D converter. This is not to say, go out and spend a ton of money, but don't go for the cheapest thing you can get. There are major jumps you can take from a soundcard A/D converter without going to the expense of Prism converters. This is one of the reasons I like the Digital Audio Denmark and db Technologies converters. I think you definitely get what you pay for up to a certain point, and then you reach a point where there is little to no improvement between a converter that costs $2k and one that costs $6k. The Digital Audio Denmark is an A/D and D/A all in one box for a very reasonable price and in my opinion stands up to the more expensive converters out there. The db Technologies converter allows you to purchase just the A/D and hits at a bit lower of a price point and also stands up to the more expensive converters.
From what I understand, many A/D converters actually use the same converter chip. Where the difference comes in is in the design and implementation of the clocking, anti-aliasing, oversampling, filtering etc... These are all very important factors.
Think of the A/D chip as a wheel. You can design a lot of things around a wheel. You can design and build a Volvo, a Honda or a motorcycle around that wheel. All of them can get you and your family somewhere, but all with varying amounts of ease and risk. Each one has different suspension, handling, safety features, etc. They all agree that the vehicle needs to get you from point A to point B. Which one would you use when going on a long road trip with your family though? Well, my guess is the Volvo. The Honda may be more fun and easier for running errands, and the motorcycle may be fun for short day rides. Preservation is that long road trip. Call running errands and the short day ride whatever you like, but when the margin for error is next to none it's not time to go taking risks. This is an item which you are placing a significant burden on. The result of your choice represents the path by which the digital preservation master is created. Chances are good you will not be going back to redigitize, and your analog master will continue to degrade. The digital file you create should not only meet preservation guidelines with regard to a faithful reproduction, but should capture enough information, accurately, to allow the opportunity for sonic restoration in the future. This is the point where poor jitter specs, signal to noise ratio, utilization of bit depth, noise from interference, and so on will be introduced and remain in your digital file forever.
The obvious argument to this thought process is that reality presents things such as budgets to factor into this equation. This is one we all know, and I'm not ignoring that fact, but we all must reference the "vision" behind our efforts, for guidance in finding our way through the myriad of obstacles in our path.
So one person says "I'd rather get a $500 sound card and preserve content than never be able to afford a Prism converter and never preserve anything" Okay that's fair. Another says "Anything less than perfect is not worth doing" And that's noble, but there is an in between here. I'd say finding a way to get something more than $500 and less than $6000 is a worthy cause, given the consequences of the choice. Maybe this means waiting for "x" more months to save/acquire funds. Maybe it means sacrificing some less significant thing(s) in the budget. And maybe you have to balance that on the other end by settling on the Volvo 240 workhorse instead of the 960 Luxury model, but at least you get away from the motorcycle. Whatever the case may be it's worthwhile to do the best you can at this phase.
My advice would be to know what you are shopping for. When your shopping for a car you've got some ideas about what features you need. What aspects are important to you in an A/D? Do you know? Are they definable? By what parameters? If you don't know, you should before making the purchase. If someone is referring an A/D to you, do they have the same goals and needs as you do? How did they choose theirs?
Pure listening tests will get you part of the way there, but the listening environment must be up to par if you are to make a decision based on that. And I'd still back up listening information with supporting data. There's a lot of subjectivity in listening tests and there is little room for subjectivity in preservation.
From: David Seubert [mailto:seubert@xxxxxxxxxxxxxxxx]
Sent: Wednesday, January 21, 2004 4:13 PM
Subject: Re: [ARSCLIST] External A/D converter with AES/EBU output
Richard, Andy and the list,
We use the CardDelux in both of our DAWs and we are very pleased with them. As I indicated in my last post, I think the DAL converters sound fine. In addition to high-quality converters, they have balanced I/O as well as digital I/O. This is something that is hard to find in a simple, inexpensive two channel card with high-quality converters. I would never use a card with unbalanced analog I/O. However, DAL is wrong if they say their cards are not affected by machine noise. Our machines run on balanced AC power from an isolation transformer, so our power is very clean, but we still got noise induced into the signal from the computer's power supply, fans or something. I don't know where the noise came from, but it was there, so we switched to external converters. I don't think there is an inherent problem with using an internal card for some types of work, as long as you are aware that there could be noise from the computer. If I had spent $6K on Prism converters, I'd probably poo-poo anybody that used a $500 sound card, but that is not as much an issue or sound quality, but of attitude.
At 10:07 AM 1/21/2004 -0800, you wrote:
>I think there is a missing piece here:
>Why are you bypassing the converters in the DAL CardDeluxe? They are
>rather competent as I understand it (it was on my short list--I ended
>up with an RME Multiface). Even Bruel and Kjaer have used it in the
>acoustics PC-based instrumentation, as I understand it.
>Http://www.pcavtech.com who actually tests cards in depth gives it an
>While you're asking for AES/EBU output and the DAL CardDeluxe is SPDIF
>in natively, DAL sells an AES/EBU and TOSLINK input adapter for $92.
>I'd be curious if the other responders to this feel that the CardDeluxe
>converters are inferior, and in what way.
>I can see applications where you'd rather route/run AES/EBU data than
>analog audio, but I'd like to understand the application. Many transfer
>suites are compact enough that the runs aren't long.
>Richard L. Hess
>Quoting andy kolovos <akolovos@xxxxxxxxxxxxxxxxxxxxxxxxx>:
> > Folks,
> > Since we're on a product-suggestion line right now, I'm looking for
> > recommendations for an external 24/96 A/D converter with AES/EBU
> > output. Not interested in USB.
> > Price range is $200-$2,000 or so, but leaning toward the middle of
> > that range. Would be going into a PC via a DAL CardDeluxe.
> > Any thoughts?
> > Thanks,
> > andy
> > *********************************
> > Andy Kolovos
> > Archivist/Folklorist
> > Vermont Folklife Center
> > P.O. Box 442
> > Middlebury, VT 05753
> > (802) 388-4964
> > akolovos@xxxxxxxxxxxxxxxxxxxxxxxxx
> > http://www.vermontfolklifecenter.org
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