Record from two mics into two separate files simultaneously?

Hi all…

I do voice-over work, and I have a client who wants me to record my voice into one file, while simultaneouly recording information from a machine that measures my vocal chord vibrations as I speak into a second file. The two files need to be separate files.

I use Audacity 1.3.9 Beta on my PC with Vista, a Yamaha mixing board, and a real, non-USB mic. The vocal chord vibration measuring machine also has a real, non-USB mic. I currently have both mics plugged into the mixing board’s Mic inputs, as opposed to Line.

Try as I might, I can’t figure out how to end up with two separate files, with the voice in one and the “vibrations” in the other. Any help y’all can give would be very much appreciated! :slight_smile:

~ Jean

The easiest way is to get hold of a second computer and send an AUX out from the mixing desk to the second computer.
Audacity can only record from one device at a time so you can’t record from a USB microphone and from your sound card at the same time.

A more complicated method that may work on one Windows computer (I’ve not tried it, so no guarantees that this will work) would be to use virtual sound card technology, such as Virtual Audio Cable to combine the inputs from the USB microphone and the computer sound card, then set Audacity to record from the virtual sound card. Virtual Audio Cable is non-free commercial software but a time limited demo version is available.

I’ll be interested to hear which solution you use.

If you used Audacity’s frequency analysis, or spectrogram display, to a (single) recording of your voice it would show the “vibrations per second”, (i.e. frequency), of your voice.

Thanks for your replies! :slight_smile:

Steve, are you saying use two computers and have Audacity running on each one, with my voice mic going to one computer and my electroglottograph (that’s the vibration-measuring machine, ain’t that hilarious?) mic going to the other? I had considered that, so glad to hear someone else mention it. (My hubby thought I was nuts.) Then I guess I’d save the files separately? I wonder if that would mess up the “simultaneous-ness” that my client wants.

Also, Steve: when you say “USB mike”, is that because the mixer has a USB input to the computer? As I said, my actual mic and that of the machine are both analog mics, not USB mics, so I"m a bit confused by that part.

Trebor, would I be able to save the spectrogram display as a separate file from the actual voice file??? If so, that might work. Hmm…

Just to throw this out there, I do have a copy of CubaseAI recording software. Would my issue be more easily solved by just using that instead of Audacity? It would mean learning a new system, but perhaps that would be good for my skillset as well as my brain!

Thanks, everyone! Your help is much appreciated. :slight_smile:

~ Jean

Yes that’s what I was suggesting. It would be fairly easy to sync up the two tracks if you make some distinctive click type sounds at the beginning of the recording before you start the proper test (these can be trimmed off later).

My mistake, I must have misread your original post.

In that case it may be very much easier.
How is the mixing board connected to the computer? Can the computer make stereo recordings with how you have it set up?
If it can, then all you need to do is to pan one of the inputs all the way to the right and the other all the way to the left (use the “Pan” controls on the mixer board to do this).
Set Audacity to record a 2 channel stereo track (Edit menu > Preferences > Devices).
Aslong as your hardware is configured and capable of doing this, you will end up with a stereo track with one input on one channel and the other input on the other channel.

I recommend that you upgrade to the current version of Audacity (1.3.13 Audacity ® | Downloads)

If you click on the track name, there is an option in the drop down menu to “Split Stereo to Mono”. (I’m not sure if this feature is in 1.3.9)
This will give you two, perfectly synchronised mono tracks.
The tracks may then be Exported as two mono WAV files by using “Export Multiple” (based on tracks)

Steve, thanks so much! I’m not terribly computer adept, so your advice is really appreciated. Especially with a client breathing down my neck. :wink:

The mixing board is connected to the computer via an ethernet cable (?) I think, and yes, it does seem that it will allow recording two channels (?) into one stereo file. I don’t see any “pan” pots on my mixer, though… there are “gain” pots and “comp” pots. There is also a button that switches between “mono” and “stereo” when I have two mics plugged in. Any suggestions?

It looks like Audacity 1.3.9 (which I have) does allow the “split stereo” function. If I use that, will Audacity actually split the two individual channels (?) apart from the stereo track, and put them into two mono tracks, i.e. so that the input from one mic (my voice) and the input from the other mic (the vibrations) will end up in separate files? If so, that’s awesome!

And I will definitely upgrade to Audacity 1.3.13. Hopefully, my old brain won’t have to learn something too terribly brand new! :slight_smile:

Looking forward to your reply…

~ Jean

What’s the model number of the Yamaha?

In Audacity 1.3.13 there are two “split” options:
“Split Stereo Track”
“Split Stereo to Mono”.

The one that you want is “Split Stereo to Mono”.

The spectrogram display could be saved as an image using a screen-grab program, (e.g. the free Windows snipping tool).

I’d never heard of an electroglottograph: apparently it involves sticking electrodes to the persons neck and passing a electrical current through them, (very Frankensteinian),

To go to those lengths the electrode technique must provide some advantage over using a microphone, if so a spectrogram won’t be equivalent to electroglottogram (EGG) …

… microphone > and > EGG waveforms that are used in the exercises


I’ve got the Yamaha Audiogram 6 mixing deck.

When I tried this, Audacity opened two track windows, which appeared to record exactly the same info in each as I used both my voice mic and the machine mic. In other words, the tracks didn’t look like one was a left channel and one was a right, they just looked the same. And sounded the same when I played them back. I tried recording both in stereo mode and mono mode (the button on the Yamaha which supposedly changes the output of the two mics) and got the same results, two Audacity tracks that look and sound exactly alike.

When I tried this, although something appeared to happen (one of the two tracks – see above – got “highlighted”) it did not result in two separate tracks. There were still the same two tracks from the original recording.

Another thing I tried was just recording into one track (I turned the “2 channel stereo track” function off) since the Yamaha seems to be OK with recording both the mics into one track. However, when I looked for the “split stereo to mono” function, it was no longer there!

I’m sorry, I’m feeling stupid and frustrated with my lack of tech-nability! (I even tried to use Cubase today, and that really had me pulling my hair out!) It seems like it should be a simple thing to record one mic into one track and the other into a second track. But perhaps that’s just impossible with Audacity?

~ Jean

I can’t get the Yamaha web site to wake up, but from what I’ve seen so far, you can’t pan sources to left and right. If you plug a live microphone into one of the two connections, it automatically appears on both left and right of the stereo show. The “Comp” control on the mixer is an on-the fly compressor to help suppress loud sounds and overloads – always a problem when you record live.

So I don’t think you can do the stereo trick with this mixer. The voice cannot be panned. We’ll find out more when the Yamaha web site gets back from vacation.


This is a closeup of my mixer. The “Pan” control lets me push the microphone anywhere from far left in your headphones (the illustration) through center to far right.
Screen shot 2011-07-17 at 10.28.44 PM.png
That’s the knob you would need to do this voice on one side and analysis on the other business.

The Yamaha website says:

Using the PAN button, you can instantly turn the two mono input channels on your AUDIOGRAM6 into a fully-panned stereo channel and vice versa.

I presume that you are inputting into channels 1 and 2?
If so, the push the Pan button down for stereo.
When you record a stereo track into Audacity, channel 1 should be recorded onto the upper channel and channel 2 onto the lower channel of the stereo pair.

A stereo track looks like this:
After the track is split it should look like this: