Recording from two microphones concurrently

[philipt18]

What's the best way to record from two microphones at the same time, so the recordings are time-synced? I assume I can record to two separate channels and split the channels into separate mono audio files later if I want, but what hardware works with Audacity for this purpose? Can I use an M-Audio MobilePre USB and hook up two microphones? Any other hardware people are using to record multiple channels? I need something that will let me record on the go, so it needs to run connected to a MacBook Pro, and preferably bus-powered.

Thanks,

Philip

[steve]

Can I use an M-Audio MobilePre USB and hook up two microphones?

I've never used one, but it looks like it could do the job.
How about asking on the M-Audio user forum? http://forums.m-audio.com/

If you end up getting one, do let us know how you get on with it.

[kozikowski]

I know you're bottom feeding ("My budget is $100 for everything") but I've used one of these for field recording...

http://www.sounddevices.com/products/mx2master.htm

Before you gasp at the price, just know that this thing is completely battery operated, has internal headphone amplifiers and control and all the microphone low-pass filters and two layers of phantom power built in. It connects to my PowerBook with the Line-In connection and a simple 1/8" to 1/8" stereo cable, so there are no USB conflicts or noise problems. Because of the analog connection, I can get 30 or 40 feet away from the computer if I need.

It will drive anything including satellite or phone company equipment.

And it will certainly give you one microphone on Left and the other on Right so you can split them up later as you need. It has a built-in slating microphone ("Friday, January third, morning shoot with Steve Henderson") and a tone generator.

This is the teensy version of the one movie crews use.

Koz

[philipt18]

My budget is not the problem. That said, however, I just realized for what I need theoretically I could plug in two sound sources directly to the mac, but let's say I have both audio sources shwoing up in the Sound preference panel - how do I record both sources at the same time? Under preferences I only see the ability to select one of the audio sources for recording. Is there a way within Audacity to record two sources at the same time? Thanks.

[kozikowski]

The Mac will not let you select two of anything. If you select Line-In--Audio Line In Port it will give you the left and right channels of that one connector. That said, you need to bring two microphones up to Line Level (high) from microphone Level (low) before you plug them in. Hence the mixing desk, field mixer, or MicPre(s) and special cables.

Even if you did manage to get two different "things" plugged into your Mac, Audacity will only record from one "device" at a time.

This said, people who deal with these problems go to USB and an external mixer that will amplify and pre-mix several sources or microphones and deliver the whole package down the USB port. If you play your cards right, Audacity will recognize all the individual pieces of the mix--up to 16. I've seen digital mixers that will do that.

But probably not for $100.

Koz

[philipt18]

Just out of curiosity, why do you keep mentioning $100?

So back to my original question, I guess the solution is something along the lines of the M-Audio MobilePre USB. Has anyone here used one and can confirm that I can get the two microphone inputs as separate channels in Audacity? Thanks.

[kozikowski]

<<<Just out of curiosity, why do you keep mentioning $100?>>>

Probably because somebody else on the forum is asking almost these exact same questions using almost the same English words. It's a popular question. Their budget is $100. That's also pretty popular, if unrealistic.

The Phrase That Pays is "Pan Pots." If the mixer will allow you to pan one microphone all the way over to the left and the other to the right, that will give you two separate mono shows with one microphone on each--after you split the tracks in Audacity.

OK, I'm just looking at the M-Audio MobilePre USB and it may not have enough controls. I need to look more.

Koz

[kozikowski]

That's fascinating. I think it uses the USB connection for power and nothing else. There's nothing so hidden as an instruction book that wants to hide something. It has many varieties of analog output and I think those may be the only outputs. No digital.

Nothing in the instructions suggests pan pots, so I think any microphone automatically gets mixed to both channels which kills it for you.

Somebody will correct me.

Koz

[steve]

I also looked at the specifications for the M-Audio MobilePre USB.
They are very vague.

I got the impression that the device will do audio in and out through the USB, and that left and right inputs to the device would go to left and right in your recording application (Audacity). If this is the case, then it will do what you want. This is just my "guess", the documentation seems very unclear.

It may be best to look for a retailer that has one in stock, and go along for a demo, armed with "Audacity Portable" on a memory stick. http://portableapps.com/apps/music_vide ... y_portable

[philipt18]

I ended up getting a MOTU Traveler as it provides 4 pre-amps that can be powered via the firewire bus, as well as by battery pack. Still having trouble getting specific inputs assigned to specific tracks. Any advice?