JACK and a (Behringer) box. Still confused.

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cdysthe
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JACK and a (Behringer) box. Still confused.

Post by cdysthe »

Hi,

I am lost in a Behringer UMC22 USB Audio Device, my external keyboard and computer DAW Reaction Waveform when trying to set it up. If I only understood the relationship between Jack, the external keyboard and my computer I may understand this but right now I am lost and do not know what goes where and why.

First which audio device should be set in Linux sound setup? The USB audio device on the built in audio? My headphones are hooked up the the USB audio device.

The keyboard is connected to the computer with USB and is recognized. The Behringer UMC22 audio Device is also connected to the computer by USB and is recognized. The DAW runs and I am able to use the keyboard to play soft synths using the external keyboard as long as Jack isn't introduced.

I have set up and are able to start the Jack server without problems using qJackCtl. The server starts without errors.:

In Jack Settings should the Driver should be set to 'alsa'? What should the 'Interface' be set to? The computer sound, The Behringer UMC22 or the the keyboard? All three are options and are available in that setting although with cryptic names. I can see that by connecting and disconnecting the keyboard and audio device.

Finally, which 'Audio Device' should I use in Waveform, Alsa or Jack? If I set it to Alsa there's lots of Input and Output options where one is Jack Audio Connection Kit in addition to many more. But if I set Audio Device Type to Jack there's three: 'System', 'PulseAudio JACK Source' and '<<none>>'.

I am watching and reading up on these things but I feel I'm missing the obvious right now so sorry for all these probably dumb questions, I have scoured YouTube but if there's howto's and/or video available elsewhere please let me know.
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Re: JACK and a (Behringer) box. Still confused.

Post by bluzee »

ALSA is the base level sound system driver. The devices can be used without jack and you can set your DAW to use ALSA then use it's menu to configure I/O.

Jack runs on top of ALSA and acts as a patch bay. When you configure your DAW or other applications to use Jack they then create input and output connections that can be connected in various ways using the connect dialogue in qjackctl, patchage or other apps. It sounds like your DAW may have a built in patch bay for Jack connections. Jack can also make midi connections between midi hardware and software.

If you start jack using qjackctl then you need to go into setup and select the audio device you wish to use it on. Most likely your UMC. The driver is indeed ALSA. Once you start then Jack is now controlling all the connections between your sound device inputs and software, interconnects between software and output to the sound device for playback. It also controls the connection between midi devices and one or more pieces of software. You may need to make these connections on your own before any sound comes through. You must now set your software to use Jack instead of ALSA.
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Re: JACK and a (Behringer) box. Still confused.

Post by cdysthe »

Hi,

Thank you so much! Just another couple of question. . My keyboard which has USB out should just be hooked up the computer along side the USB audio device? This means I have two external USB connection, the Behringer and the Korg keyboard. That will work if set up correctly?

And then I wonder whether I need to use Jack at all. I am going to do all my work within Waveform. The only two external connections is the Behringer and the Korg keyboard.
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Re: JACK and a (Behringer) box. Still confused.

Post by bluzee »

Yes, just plug your keyboard into another USB plug. It will show up as an ALSA midi device. If you choose to use Jack then there becomes two choices as Jack can use both ALSA midi and Jack midi at the same time. Some apps will only work with Jack midi connections. Sometimes keyboards only show up as an ALSA midi device in Jack, sometimes they show up as both Jack and ALSA midi. If you end up with the first situation there is a program called a2jmidid which you can run that will make your keyboard also show up as a Jack midi device.

You might not need to run Jack if your DAW can manage all the connections internally and the latency is acceptable to work with. Most things I use will only work with Jack so I'm not sure what it's like to work with ALSA on it's own.
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Re: JACK and a (Behringer) box. Still confused.

Post by cdysthe »

I have played around with this some more. In Traction Waveform there's two options for "Audio Device Type". either Alsa or JACK. Setting Alsa gives me a lot of input/output options, but choosing JACK I only get three. If I only was sure what to set there I think I can deal with the rest. I have a feeling I am missing somethings fundamental or Traction Waveform is difficult to understand in this regard. I have used Waveform before on friends Windows and Mac systems where I haven't had to deal with any setup, so I know the use of Waveform, but not the setup.
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Re: JACK and a (Behringer) box. Still confused.

Post by bluzee »

If you are not using Jack then choose ALSA and assign I/O using that menu list of options.

If you run Jack the I/O is handed off to it. I/O assignments are made in Jack patchbay software. Qjackctrl has a connections menu. Programs like patchage or Catia generate graphical views of all the available I/O and let you make visual connections between things. I'm not familiar with Traction Waveform and if it has a graphical patchbay feature built in.

For a two channel setup where basically everything is contained inside the DAW perhaps just try starting off with ALSA.
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