Re: [PLUG] USB audio interface w/linux support?

[Isaac Bennetch <bennetch@gmail.com>]

Hi,

On 6/13/11 10:51 AM, Adam Zion wrote:
> OK, here's an oddball question.
>
> I'm looking to play guitar on Second Life- seriously, people tip you
> to do this- and I'm told that a good thing would be to use a USB audio
> interface to combine the two audio channels- guitar (from a pickup)
> and voice- into a single mono channel + then feed this to a stream.
>
> I've seen a simple Behringer USB interface, but it appears to have
> only RCA inputs, where I'd need dual 1/4" inputs. Any suggestions for
> a USB audio adapter with 1/4" inputs that supports linux?
>
> Yes, I've Googled- that's where I found the small Behringer interface
> I mentioned.

What you need is a mixer -- either software or hardware -- to take in 
the mic and guitar signals and allow you to control the mix between the 
two. A decent sound card can do this (well, even a cheap sound card, but 
then you're putting more effort on getting the signal in than it's 
worth). You could also do it with a traditional audio mixer and send the 
outputs of that to whatever sound card you have laying around.

If it were me, I'd buy a cheap mixer and feed the output of that to my 
sound card. Some mixers even have USB outputs and do the analog to 
digital conversion so you don't need to use your sound card at all, 
which can help with the quality if you've got a cheap card. Using a 
mixer gives you direct control over the mix between the microphone and 
guitar...doing it in software means you'll have to get to the audio 
mixer settings to tweak the mix, which could be a problem if you're in a 
full screen application.

I guess it also depends what type of equipment you already own. Most 
sound cards have a mic and a line input; if you've got a cheap little 
computer  microphone that works with your existing soundcard you can 
probably find a way to get the guitar to the line input, mix it through 
the software audio controls, and you're set. I'm not sure offhand if the 
guitar pickup will have enough signal to drive a PC soundcard, and it 
limits your microphone choices. So one option is go with a small mixer 
and microphone, and feed it to your soundcard from the main outputs of 
the mixer.

The SM-58 made by Shure is a cheap, solid, quality microphone. I'd 
recommend that you get one and a decent boom stand (if you don't already 
have a microphone, of course).

A few mixers offhand:
* Behringer 302USB (not yet released, needs an adapter to get your 
guitar in, but has the USB interface. No word on Linux compatibility).
* Mackie 402-VLZ (doesn't have USB)
* Either the M-Audio Fast Track or MobilePre look like they would be 
perfect -- but I'm not sure about Linux support. It's not claimed on the 
M-Audio web site, but a quick Google search suggests that both can work.

In the time it's taken me to write this, Bhaskar has also written about 
the MobilePre, so that helps fill in what I didn't know about Linux 
support. That's what I'd do -- get an M-Audio MobilePre. They've got the 
best of both worlds -- it's a USB interface, so you don't have to worry 
about interfacing to your sound card, and it's got knobs on the front, 
so you don't have to dig down in menus just to turn your voice up a 
little bit.

Regards,
~isaac
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