Records only left stereo track

[g-raf]

I'm using a usb soundcard (m-audio fast track pro), Jack Audio Connection Kit and Audacity to record audio with a mic. The audio only records on the left stereo track. In the qjackctl settings, i have audio set to duplex and i have audacity set up to record stereo tracks. I'm not sure why only the left stereo track is capturing audio. This could have something to do with qjackctl, audacity or alsa settings, but I'm not sure how to start fixing it. I posted a vlog about this problem as well.
http://www.archive.org/download/VlogAbo ... /vlog1.mp4

[g-raf]

My alsa configuration only recognizes HDA Intel as a default mixer track and there is no way to configure the settings for each usb audio mic input in alsa. I would like to configure both mic inputs to record in stereo. Please share ideas, thanks.

[g-raf]

I made a new 10min vlog about the problem of ALSA recognizing the two mic inputs on M-Audio Fast Track Pro as left/right channels rather than as separate stereo or separate mono tracks. Click on the following link to download the vlog as an mp4 file: http://www.archive.org/download/Vlog2Au ... /vlog2.mp4

[steve]

In the "Connect" screen of Jack Control, do you have 2 inputs shown for your sound card?

[steve]

I have a look at your video, and at the Fast Track manual, and I think there may be some confusion about what the Fast Track device can do.
M-Audio give the impression that you can record 2 stereo inputs(4 inputs), but looking closer I think that is very misleading. With appropriate driver support, the device can handle 2 analogue inputs and 2 digital inputs. The left analogue input socket is mono and the same for the right analogue input. Either of these may be used with 3 pin XLR microphone lead, mono or stereo 1/4" jack. Using a stereo 1/4" jack is NOT for recording stereo - it is for connecting to a mono source, but with a 3 contact "balanced" output (basically the same as the 3 pin XLR but in a 1/4" jack format).

To record a stereo analogue input you need to use both the Left and Right analogue inputs.

There is no point recording a single mono microphone as a stereo track as even if you are able to do this, both channels will be identical, and as you say on the video you can easily create a 2 channel track from a mono track by duplicating the track and joining them (useful if you want to do stereo processing, such as adding stereo reverb - simple things like "pan" can be done with mono tracks).

In Jackd, you should see 2 inputs, one for left and one for right. If you want to record a microphone to both left and right of a stereo track in Audacity, set Audacity to record 2 channels, start recording and hit Pause. Open the Connect screen of Jack Control and expand the sound card entry in the left panel. If your microphone is plugged into the left input, then use Jack Connect to join the left microphone input to both left and right inputs of the sound card (in the Right panel). When you "un-pause" Audacity, the microphone will be recorded onto both the left and right channels of the stereo track (of course it will still be mono).

[g-raf]

I tried your suggestion, but it didn't work. Did i do it right? I paused audacity in the middle of recording, open the jack connections and they were already connected like you said.

[steve]

Did i do it right?

Not quite.
That's showing;

capture 1 ________ In 6
capture 2 ________ In 7

which is exactly what you want if you are using 2 microphones,
but for one microphone you need to click on "capture 1" so that it is highlighted (as shown in your picture) and "In 7" so that it is also highlighted, then select the "Connect" button. You will see that an extra connection is made so that capture 1 is now connected to both PortAudio inputs.

Note that each time you do this the PortAudio numbers will change, but that does not matter as long as you connect it to both PortAudio inputs.

I think that capture 1 will be the left microphone input.

Unfortunately, I don't think that Jack will remember this setting, so you need to repeat it (in record-pause mode) every time you want to record one input onto both tracks. Most times it's probably easier just to record onto one track and duplicate the track if required.

Of course there are more exciting things that you can do now that you know how to rout your microphone through to Audacity. For example, if you install Jack Rack, you can load up some LADSPA effects into Jack Rack, then set Audacity recording and hit "P" (pause). Then go to Jack connect and rewire the whole thing so that your "capture 1" (microphone) connects to the inputs of Jack Rack, and the outputs of Jack Rack go to the PortAudio inputs. When you start recording you have live REAL-TIME EFFECTS on your microphone. It may not be very useful, (no more useful than your video cheese), but it's fun.

[g-raf]

stevethefiddle, thank you so much. This works perfectly. Do you use Gnome ALSA Mixer, by chance? I'm trying to figure out how I can set up the Fast Track Pro usb soundcard as the default mixer track so that i can use it in the mixer.

[steve]

I use the "GNOME Volume Control" and the "Pulse Audio Volume Control".
The GNOME Volume Control controls the hardware drivers, and the Pulse Audio Volume Control controls the audio data streams.
The GNOME Volume Control can be configured to be the mixer for any drivers that are installed by simply selecting the required device from the button at the top of the mixer.

When using Jack (which I don't very often), the set-up is slightly different.
Jack is configured to use Pulse Audio, and the Pulse Audio Volume Control is used to select which devices will be used by Jack. The GNOME Volume Control is then used to adjust input and output levels of the chosen device. It's a bit complicated, but very versatile.

On my laptop I frequently want to switch between the (poor quality but convenient) on-board sound card and the (better quality but it needs plugging in) Behringer UCA-202 USB sound card. To do this is just a matter of opening the Pulse Audio Volume Control and selecting one or the other (or both simultaneously) as the default device. Input and output are selected independently. Of course this only applies if you use PulseAudio.