Cabling: how do I run stereo audio from my mixer to my breakout box?

December 20, 2005 12:27 PM

Audio Cables 101: tell me exactly how to feed a stereo mix from my mixer to my breakout box.

This cannot be hard. I have got to just be stupid. Please take pity on me. Here's what I've got:

Mixer: a Yamaha MG10/2.
Breakout box: an M-Audio Fast Track USB

Simple task: take a stereo mix from the mixer and feed it into the breakout box. The mixer has a variety of output options -- stereo RCA, stereo 1/4" headphone jack, etc. The breakout box has two inputs -- a stereo** 1/8" minijack, and an XLR female jack.

(**Is it possible? fathomable? reasonable? that M-Audio would have a mono input jack here?)

I ought to be able to do something simple like run an RCA-pair-to-stereo-1/8" cable from the mixer to the jack on the breakout box and just call it a day. And I tried that, and it didn't effin' work. Buh?

I've been getting by on a frankensteinian kluge, handling each half of the stereo singal with a seperate solution:
- single-RCA-to-1/8" running from one channel of the mixer's stereo RCA out into the minijack on the box
- 1/4"-phone-jack-to-XLR-male cable running from an unrelated output channel on the mixer into the XLR-in on the box.

And doing some crazy panning and leveling control on the mixer to get these signals isolated to left-and-right respectively and approximately equalized in volume.

And that's been working, but it's a pain in the ass and just seems wrong besides. And all I can figure is that I am just plain missing something, something obvious/essential/basic. Help! Reveal my fundamental ignorance!

posted by cortex to technology (11 comments total)

Uh, your breakout box only has a mono 1/4 input, according to the website. What you're missing is a sound card with stereo inputs.
posted by jon_kill at 12:40 PM on December 20, 2005

Heh. Yes, the 1/8" minijack-in I was talking about is a 1/4". That's what I get for posting on the fly from memory.

But is it explicitly mono? That's partly what I'm afraid of. The text on the site says: "switchable instrument/line input (1/4”)" and I had been operating on the naive, hopeful notion that it'd be a stereo TRS-style jack rather than a mono TS-style jack.

Being wrong about that would certainly clarify things a bit, but it also leaves me confused further:

Why, if I have a mono 1/4" jack and a (mono?) XLR jack, can I get from out of that box and into my computer a stereo signal with the 1/4" input delivering one isolated half of my mixer's stereo signal and the XLR delivering the other isolated half? Have I been distracted by the box's assignment of it's two mono input channels to complementary side of it's stereo output channel?

And if that's the case, am I going to (with this pair of mixer-and-box) every going to get less frankenstein?
posted by cortex at 12:49 PM on December 20, 2005

What jon_kill said. You prolly need something like a MobilePre instead.

Once you've got enough channels to work with, use nothing but XLRs unless you have no other choice. Markertek is a good supplier of such cables.

On preview: The XLR is a balanced connector. Are you sure you've got real stereo, and not some strange half-signal which is causing phaseyness that sounds like stereo?
posted by Triode at 12:54 PM on December 20, 2005

Clarifiying -- the output to your headphones is 1/8" stereo. The Guitar input is a 1/4" plug -- the question before the house is -- is it stereo or mono input?

I think your interface is not designed to take a stereo input. There's only one channel of a-d conversion (that's why it is cheaper!) The box has some built-in reverb functionality -- that's how it takes a mono signal and makes stereo.

Ask M-Audio if the 1/4-inch input jack is mono or stereo; I can't tell from the info on the page.

This will probably suit your needs better -- you already have instrument / mic preamps on your mixer, so what you need is hi-quality analog/digital conversion in stereo. Also you will get higher-quality conversion out of M-Audio's "audiophile" line than their basic line.

For the same $ as what you have, and far higher quality (if you can deal with a PCI card install), get this.

But to answer your "can I get less Frankenstein" with this box? I think no.
posted by omnidrew at 12:54 PM on December 20, 2005

omnidrew: there's reverb on my Fast Track? Are you looking at the same thing as I am?

Triode: I wouldn't know phasiness if it punched me in the face. I can tell you only that I've got mixer-left-to-XLR, mixer-right-to-1/4" and am getting a stereo signal into my computer with no bleed between the two channels. ?

PCI card is out -- this is a laptop setup. That's what motivated the move to a small, inexpensive breakout box in the first place: none of my equipment is awesome enough to make the soundcard a serious fidelity bottleneck at this point. :/
posted by cortex at 1:04 PM on December 20, 2005

mono vs. stereo: It definitely is mono. jon_kill for the win on that! (From the context of some product support questions on the m-audio site that refer to the two inputs as being mono to left and right of the outpet respectively.)
posted by cortex at 1:11 PM on December 20, 2005

Reverb -- oops I misinterpreted the phrase "The included GT Player Express software gives you killer effects and virtual stomp boxes" - still wonder tho why they bothered with the mono-stereo switch...

Given that you are on a laptop, definitely ditch the FastTrack and get a Transit. All you need is stereo in and out from your machine -- besides, playback will likely sound better thru the M-Audio box than the internal outputs.
posted by omnidrew at 2:09 PM on December 20, 2005

Well, that might be a plan. I appreciate all the input, folks. Thanks for pointing out the obvious.
posted by cortex at 2:19 PM on December 20, 2005

omnidrew, the mono-stereo switch on the box is handy if you're only using one input -- otherwise you'd be stuck monitoring on only one side of your headphones, for example.
posted by cortex at 3:06 PM on December 20, 2005

Sorry if I misunderstand some of the things going on in this thread, reading some of it made me feel a bit drunk..

What you're doing sounds a little rigged, but workable. Adding a Line-Mic Level adapter might be appropriate, I wouldn't be surprised if you overloaded the input on the FastTrack, attenuating the signal before it gets to the mic-level input would be appropriate. Of course that adapter is $50. But then you'd be working with a set of outputs on the mixer that are supposed to be connected at least, so panning, etc.. would be very straightforward.

If you have aux outputs, with a master aux output level control, you could assign channels to your aux output, and try to use the aux output level control to "calibrate" the difference between the two signal levels. I guess..
posted by Jack Karaoke at 5:23 PM on December 22, 2005

The obvious continues to be obvious. My Frankenstein kluge continues to work just fine; if (when) it ever stops being enough, I'll drop some cash on a proper multi-channel firewire interface, I think.
posted by cortex at 8:52 AM on June 28, 2006