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Digital audio cable question

Posted: Mon Sep 26, 2011 7:39 pm
by derFunkenstein
I have an Alesis Multimix 16 USB (16-in, 4-out mixer) with an S/PDIF output, which outputs the main outputs (bus 1/2). I want to record it via the S/PDIF input of my Mbox 2. Both the mixer and my interface have the RCA-looking S/PDIF connector, so I'm good there.

My question is, can I just use any old RCA cable? Or are the special digital RCA cables absolutely necessary?

Re: Digital audio cable question

Posted: Mon Sep 26, 2011 7:55 pm
by StefanVonS
75ohm RCA cable is fine... which I believe is what all RCA cables are, however, I'll double check quick to be sure.

EDIT:

From Wikipedia:

Although nearly all audio-visual connectors, including audio, composite and component video, and S/PDIF audio can use identical 75 Ω cables, sales of special-purpose cables for each use have proliferated. Varying cable quality means that a cheap line-level audio cable might not successfully transfer component video or digital audio signals due to impedance mismatch and poor shielding quality (causing signal-to-noise ratio to be too low). Cables should meet the S/PDIF specification as defined by the international standard IEC 60958-3 for assured performance.

Re: Digital audio cable question

Posted: Mon Sep 26, 2011 8:15 pm
by just brew it!
So it would seem the answer is that *almost* any old RCA cable will do, but some really crappy ones might not cut it.

Re: Digital audio cable question

Posted: Mon Sep 26, 2011 8:50 pm
by destroy.all.monsters
Getting HOSA brand spdif cable is cheap as dirt and works fine. Better and cheaper to just do that than experiment.

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 11:48 am
by derFunkenstein
suh-weet. I mean, I own RCA cables so I can try one before I order, I just wanted to make sure I wasn't going to fry something first. I'll give it a go, but I've had good luck with Hosa-branded cables; they're what Guitar Center uses for their own store line of instrument and XLR cables, and they've always been good to me too. Thanks all.

If the cable I have won't work I'll grab a special-purpose one. Being a digital signal, it should be a matter of "it works" or "it doesn't work", not "working with varying degrees of quality" at least...

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 11:53 am
by morphine
derFunkenstein wrote:
suh-weet. I mean, I own RCA cables so I can try one before I order, I just wanted to make sure I wasn't going to fry something first. I'll give it a go, but I've had good luck with Hosa-branded cables; they're what Guitar Center uses for their own store line of instrument and XLR cables, and they've always been good to me too. Thanks all.

If the cable I have won't work I'll grab a special-purpose one. Being a digital signal, it should be a matter of "it works" or "it doesn't work", not "working with varying degrees of quality" at least...

Worst thing that can happen is that you don't get a sync, or can't use the highest sampling rates available.

But unless the cable you're using is especially nasty, you'll do fine.

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 11:56 am
by UberGerbil
Monster Cables is unhappy with this thread and would like you all to keep this information to yourselves. Bits much prefer to be wrapped in gold.

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 12:06 pm
by cphite
UberGerbil wrote:
Monster Cables is unhappy with this thread and would like you all to keep this information to yourselves. Bits much prefer to be wrapped in gold.


It always amazes me how much of a premium people are willing to pay for something that offers absolutely no additional value to what they're using it for.

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 12:11 pm
by morphine
cphite wrote:
It always amazes me how much of a premium people are willing to pay for something that offers absolutely no additional value to what they're using it for.

Simply a matter of convincing them that what they're buying is necessary or a lot better than the alternative. Marketing 101.

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 12:34 pm
by derFunkenstein
While I personally won't ever go premium for cabling, I can see where analog cable might benefit from better shielding, thicker wires, etc. But digital? Come on, guys. :p

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 1:21 pm
by cynan
Unless you have a high-end digital source (dedicated DAC), and are worried (anal retentively preoccupied) about getting every bit of digital information to said DAC, as may be warranted in precision critical applications (ie, commercial audio mixing, product testing, or if you have a very high-end/resolving audio system), then any old RCA cable should work fine. Most people don't have equipment that can detect, or themselves can't detect/don't care about, the odd dropped bit for normal A/V applications.

However, the crappier the RCA cable shielding, and the higher the impedance, the shorter the distance it will work over: Any old RCA cable should probably work (unless it's real garbage) for 6-8 feet or less. But if you want to do 20ft runs or more, you might need to invest in something more substantial. I like the RG6 cables from monoprice. I use them for everything at home from analog interconnects to digital coax to subwoofer cables. If you are/know a cable installer, and can get free RG6 cable, you can simply crimp RCA ends on that to make excellent digital cables...

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 1:59 pm
by derFunkenstein
I only need about 3 feet to get from the digital output on the mixer to the digital input on the Mbox. I'll definitely keep it as short as possible.

The goal here is to get 4 discrete audio channels - I'll use the pre-amps on my Mbox for 2 and hard pan the two pre-amps on the mixer when I bring them in so I have as much control as possible over those 4 mics.

I'm also kicking around the idea of getting something like a Fast Track Ultra (running Pro Tools 9 now so I am not locked into Avid hardware anymore), which would be a big step up over at least the pre-amps on the mixer, but I don't know how often I'd use more than 2 pre-amps, and the pres on the Mbox are already pretty quiet. I don't think it'd be enough of an upgrade to warrant spending the money.

Re: Digital audio cable question

Posted: Wed Sep 28, 2011 2:14 pm
by DLHM
Grab some RG6 and some gold RCA connectors. and it will be the best on the planet.

http://www.radioshack.com/product/index.jsp?productId=2103724