VO-BB - 20 YEARS OLD!

[Bish]

Currently, I feed all audio through a Mackie 1202VLZ3. The main XLR outs (both L&R) feed a Zoom H4n which is just serving as the USB interface for the Mac Pro. I want to change this out as using the H4n (a good field recorder) as just a USB interface is overkill.

My first thought was to just buy a good/cheap (two-channel) USB interface. I was considering things like the Lexicon Lambda or various M-Audio solutions when I started to root through my USB connectivity issues and realized that there was a perfectly good unused Toslink s/pdif input sitting there!

It seems that we always think of USB interfaces when trying to hook up external audio chains, but what are the pros/cons of using the optical path? At the cheap end ($33), the Behringer UCA222 will take two unbalanced line inputs and provide both USB and toslink s/pdif optical output. It'll have to be plugged into USB for power, but that's not an issue.

Does anyone have any experience with using the optical path on the Mac or with the UCA222 (or any other) basic optical A/D converter?
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Bish a.k.a. Bish
Smoke me a kipper... I'll be back for breakfast.
I will not feed the trolls... I will not feed the trolls... I will not feed the trolls... I will not feed the trolls.

[Mike Sommer]

I would just stay with a USB or Firewire interface.

Optical is known to have jitter, or sound smeary.
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The Blog:
http://voiceoveraudio.blogspot.com/

Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.

[Billy James]

So even USB is better than optical?

That's a bit of a surprise to hear, considering what I would imagine are the relatively low throughput demands of the typical dry voice track.

I thought optical was supposed to be the King Shiz interface for audio input/output. But like many here, I trust Mr. Sommer's opinion implicitly on all things audio. If he's that definitively unenthusiastic...

Rats. And I just found a really cheap optical cable in the clearance bin at Guitar Center too.

(Hmm. Come to think of it, maybe that proves the point...!)

[Bish]

I think I'm just having USB issues. I'm not down on the quality of the USB A/D process itself, it's just that I seem to spend too much time tracking down an annoying USB "whine" from my current interface (when working at 48KHz). Intermittently, it comes through from my line-outs and is a real annoyance when I'm mixing or just trying to listen to something. I'm constantly having to pull the USB cable to get some silence! Thankfully, it's not apparent in the recording path. Also, I have a limited number of ports and far too many USB devices. The noise is independent of whether I'm connected to a rear, front or hub port.

I'm currently looking at a firewire solution. The Apogee Duet looks to be nicely integrated with the Mac (and the Soundtrack Pro software) and while not cheap, it looks like a good solution with it's +4db balanced XLR inputs that will feed directly off my Mackie's main outs. Plus, it's very appealing to my Mac sensibilities
_________________
Bish a.k.a. Bish
Smoke me a kipper... I'll be back for breakfast.
I will not feed the trolls... I will not feed the trolls... I will not feed the trolls... I will not feed the trolls.

[Mike Sommer]

It was to be the shiz. Great for data.

I cant find the paper but this from Wiki pretty much sums it up:

"S/PDIF lacks flow control and retry facilities, which limits its usefulness in applications outside of synchronous playback.
Because the receiver cannot control the data rate, it instead has to avoid bit slip by synchronising its conversion with the source clock. This means that S/PDIF cannot fully decouple the final signal from influence by the analogue characteristics of the source or the interconnect, even though the digital audio data can normally be transmitted without loss. The source clock may carry inherent jitter or wander, and noise or distortion introduced in the data cable may further influence the process of clock recovery. If the DAC does not have a stable clock reference then noise will be introduced into the resulting analogue signal. However, receivers can implement various strategies which limit this influence.
TOSLINK cables do not work well (and may even suffer permanent damage) if tightly bent or squished by, say, a misplaced foot, and their high light-signal attenuation limits their effective range to 6.1 metres (20 ft) or so. On the other hand, TOSLINK cables are not susceptible to ground loops and RF interference, like coaxial cables."

NOW If you are talking about ADAT Lightpipe, that's a different story. But these devices usually talk to themselves- like the The PreSonus FireStudio Lightpipe, this unit still connects to your computer via Firewire.
_________________
The Blog:
http://voiceoveraudio.blogspot.com/

Acoustics are counter-intuitive. If one thing is certain about acoustics, it is that if anything seems obvious it is probably wrong.

[Billy James]

Hmm. So, as it turns out, optical too often sounds like ACTUAL shiz.

This tech nugget brought to you by vo-bb.com -- where anytime can be Sommertime.


Thanks Mike. Great as usual.