Cadence's JACK duplex operation problems

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unfa
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Cadence's JACK duplex operation problems

Post by unfa »

This started a few months ago.

I want to use two audio interfaces with JACK, one for input, another one for output.

Input is Zoom H2, external via USB
Output is Intel Conexant Analog, built-in

I used to do this and everything worked fine, but now when I select two interfaces, I get only Conexant Analog used for both input and output.
How do I know? When I connect system:capture to system:playback I hear my buil-in, poor quality laptop mic. D'oh!

What's more strange - when I select Zoom H2 fro both input and output, it indeed works like this. Why is this strange? Becasue for years I wasn't able to do that, Zoom failed to work in duplex mode, it was capture only or playback onle, but not both. Now I can use it in duplex, and it sometimes even stops monitoring it's input (whitch is impossible to disable - or at least I can't disable input monitoring in the Zoom's USB I/F mode).

So one thing seems to broke, another seems to fix itself.

Now the only way to use built-in output, and external input is by using Conexant for both and running alsa_in process (command: alsa_in -d hw:H2 -J AUX), but this creates a need for manually routing all input to AUX input instead of system one - especially daunting for Ardour sessions I think.

Anybody has similar expirience? Maybe it's me doing stuff wrong? :)

Bless!
Last edited by unfa on Sat Feb 14, 2015 4:39 pm, edited 1 time in total.
bassmannate
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Re: Cadence's JACK duplex operation problems

Post by bassmannate »

Glad to see that I'm not the only one experiencing this. I've got the same problem only I'm using a M-Audio Fast Track Pro. Cadence seems to be completely ignoring the duplex settings and using the device that is in the greyed out dropdown box. This works great with the built in audio device.

However, the Fast Track Pro splits up the inputs and outputs to separate devices. I can get audio in and I can get audio out, but not at the same time. It always follows what's in the "Device/Interface" field even if it's greyed out and ignores the "Input Device" and "Output Device" fields.

Other than that, I'm loving Cadence! Just downloaded and installed KXStudio yesterday and just love how intuitive it is! No PulseAudio to work around or anything!

Edit: I just went in and looked at ~/.config/jack/conf-jack1.xml and noticed that I have 3 entries for my device.

Code: Select all

<option name="capture">hw:Pro,1</option>
   <option name="playback">hw:Pro,0</option>
   <option name="device">hw:Pro,1</option>
I can only assume that <option name="capture"> corresponds to the input field, "playback" corresponds to the output field and "device" is the Device/Interface field. I just tried commenting out the "device" line and restarted jack. It works! I now have input and output on the device. Looks like an error on how Cadence is writing the xml file? Perhaps if duplex is checked, it shouldn't be writing that line.

Further testing showed something else interesting. I went into the settings in Cadence and changed the buffer size and saved the settings. After restarting jack, I went back into Kate. Of course, it said that the file had been changed and gave me the choice to reload the xml file. Lo and behold, the "device" line is now gone.
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Re: Cadence's JACK duplex operation problems

Post by unfa »

Thanks, falktx :)

I'm also very happy to hear a new KX Studio ISO is coming up, I'm using 14.04 for a long time now, and I got some issues, so I'll probably take some time to switch to the never one (start over, reconfigure it to my needs).
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