Selecting Jack input

[worik]

Frinds

I am running audacity 2.0.5 on linux mint.

I am using a PreSonus AudioBox USB device.

The PreSonus needs to have audacity's output sent to input ports 7,8 to get to the headphone jack, which I require. But whenever Auacity starts to play it connects to inport ports 1,2 (as "portaudio")

Is there a way to tell it to use sinks 7,8 each time?

cheers
Worik

[steve]

Unfortunately Audacity does not have "channel mapping" for input channels, so "input 1" of the audio device always goes to the first input channel in Audacity, "input 2" to the second, and so on. To record inputs 7 and 8 you will need to either:
1) Use software to remap the inputs to different channels before it gets to Audacity
or
2) Record 8 channels, and delete the unused tracks after recording.

The second option is the easier, if you system can handle recording 8 channels simultaneously.

The first option is better, but can be tricky to set up. You would need to install Jack Audio System. When using Jack Audio System, you can route audio signals between applications. You would set up a "dummy" application (such as "Jack Mixer") to which you would connect inputs 7 and 8 from your sound card, then open Audacity, set it to use Jack Audio System as the "host" and the "dummy" application as the recording input.

[worik]

Thank you for clearing that up

Worik

[worik]

My problem is I am using audacity to over dub tracks, so I need to monitor what is recorded already through the head phones.

Since audacity resets its connection t inputs 1,2 each time it plays (not on startup, later) I need to reset the connections to inputs 7,8 each time.

Hw can I use "1) Use software to remap the inputs to different channels before it gets to Audacity"? My channels are coming out of audacity. If I could tell audacity/portaudio to connect to JackMix each time it starts to play that would achieve my ends. But how do I do that?


Is this not possible to use Audacity/PreSonus for this?

cheers
Worik

[steve]

Ideally, we would just connect Input 7 of the sound card to Input 1 of Audacity, and Input 8 of the sound card to Input 2 of Audacity, then just leave it like that.

Unfortunately, that does not work because Audacity creates new input and output ports when it needs them, then closes the ports "on stop", and each time it creates ports, they are numbered differently. This is why we use a "dummy" device between the sound card and Audacity. The dummy device can be any Jack application that has at least 2 inputs and 2 outputs that can be set to do nothing. I used to use an instance of "Jack Rack" with no effects in it, but now I use "Jack Mixer" (which allows me to control the audio input level in real time).

So with Jack Mixer launched:

• In Audacity, "Transport menu > Rescan Audio device" (If necessary) so that Audacity can see Jack mixer. (Audacity only looks for available ports when Audacity is launched, so if you add Jack Mixer after Audacity you will need to "rescan").
• Add a stereo channel to Jack Mixer and name it "PreSonus 7 8" (or anything you like)
• Connect the input of jack Mixer to inputs 7 and 8 of your sound card to "PreSonus 7 8" of Jack Mixer
• Using the device toolbar in Audacity, select "Jack Mixer" as the recording input, and "system" as the output. Audacity will now automatically connect to the mixer when you start recording.

If you are using QJackCtl, you will see Audacity automatically connect to the mixer if you look in the "Connect" window.

When recording:

Connect.png (25.43 KiB) Viewed 1445 times

and like this when overdubbing:

Connect-overdun.png (25.03 KiB) Viewed 1445 times

[worik]

That works for me.

"Using the device toolbar in Audacity, select "Jack Mixer" as the recording input, and "system" as the output. Audacity will now automatically connect to the mixer when you start recording." is the key. Though I set "Jack Mixer" as output and system as input, naturally.

cheers
Worik