A/D and D/A configuration

[cantabile]

I need to record (my) solo voice or solo voice plus keyboard. I would like to monitor the recording real time through either loudspeakers or (preferably) a headphone.

I am considering buying an A/D converter and a D/A converter, to be connected to a laptop computer. It seems that the first step is to consider the configuration, e.g. combined unit vs. separate units.

My questions are -

1. Is there any drawback (e.g. problems with grounding, master-slave issue, clock incompatibility etc.) about buying separate A/D and D/A from different manufacturers, instead of buying a combined A/D-plus-D/A unit like MOTU or UA 2192? Will I be missing important functions or compromising anything by going separate? Will it be invariably difficult for the A/D and D/A from different manufacturers to work together (without crashes, sync problem or slow latency)?

2. In general how are the separate A/D and D/A connected to the laptop? It seems from this forum that there are (at least) three options -

(a) some of you connect both the A/D converter and the D/A converter via spdif to a third interface (such as an spdif to firewire converter), which in turn is connected to the laptop via a single firewire cable.

(b) some of you connect the A/D and the D/A directly to the laptop via (two) firewire cables. In this case you may need two firewire ports on the laptop.

(c) some of you connect the A/D directly to the laptop via toslink, and the D/A directly to the laptop via firewire.

Which option is better in your experience/opinion, or is there a fourth (or better) option that hasn't occured to me?

3. Should I be looking for A/D with ADAT?

Thanks for your help. I need to get this clear before proceeding further.

 

[dgatwood]

(b) some of you connect the A/D and the D/A directly to the laptop via (two) firewire cables. In this case you may need two firewire ports on the laptop.

By definition, anything that connects via FireWire is NOT an A/D or D/A converter. It is an interface. An A/D or D/A converter deals only in S/PDIF (TOSLink), AES/EBU or ADAT Lightpipe.

Also, if you're dealing with two FireWire audio interfaces from different manufacturers, it is unlikely you will get them working together reliably. That said, I've also never seen any FireWire interface that didn't provide both inputs and outputs, so the issue is largely moot in that case. Oh, okay, so you could use a camcorder and that would typically provide only input or output at any given time, but....

(c) some of you connect the A/D directly to the laptop via toslink, and the D/A directly to the laptop via firewire.

While you could do that, the on-board S/PDIF support in most computers is intended primarily for connecting to home theater equipment, so I'd be amazed if it were up to the latency standards needed for recording. I've never tried it—that's more of a gut reaction than anything else—but it doesn't seem like a path that is likely to meet with much success.

Also, every piece of audio gear I've seen for doing A/D and D/A has been S/PDIF coaxial rather than optical, while every laptop TOSLink connector I've ever seen has been S/PDIF optical. Just to do conversion back and forth, you're looking at $50 worth of format converters. So for all practical purposes, this option is also out.

IMHO, your best bet is to just get a decent two-channel or four-channel audio interface and don't bother with stand-alone A/D or D/A converters.

 

[Ethan Winer]

I need to record (my) solo voice or solo voice plus keyboard.

All you need is a basic USB or Firewire sound card. There are so many affordable models out there that all work fine I won't even suggest one in particular. But you also need a minimal mixer, connected as described in this article from EQ Magazine:

Using a Mixer with a DAW

--Ethan

 

[cantabile]

thanks

Thank you, dgatwood and Ethan, for your advice.

I should explain that I'd been thinking about buying separate A/D and D/A (such as Lavry or similar brands) in the hope of achieving better sound and higher flexibility than what is achievable by integrated interfaces like Edirol or EMU. The threads I've read in this forum also gave the impression that integrated interfaces may not compare well with separate A/D and D/A in terms of audio quality.

These days there are D/A converters that provide not only spdif but also a built-in computer interface. Examples include Apogee mini-dac with the firewire option, or Benchmark DAC1 with USB. Both of them provide a convenient one-box solution between the computer and the pre-amp. If I needed only D/A but not A/D, I'd probably try out one of those. Unfortunately I am looking for not only D/A but also D/A. Hence the agony.

Given the difficulties you described with separate A/D and D/A in computer recording, however, I think I'll just go for a firewire interface with built-in A/D and D/A.

 

[Ethan Winer]

The threads I've read in this forum also gave the impression that integrated interfaces may not compare well with separate A/D and D/A in terms of audio quality.

That's just wrong. These days all but the cheapest POS sound cards are audibly transparent. If you have quality issues I promise that your sound card is not the weak link. Far more important are the microphone you use and the acoustics of the room you record in.

--Ethan