How do I configure Qjackctl parameters (with Alsa USB device)?

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ComposerGuy
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Posts: 5
Joined: Thu Mar 25, 2021 1:12 am

How do I configure Qjackctl parameters (with Alsa USB device)?

Post by ComposerGuy »

Hi,
Still struggling a lot with the audio setup to make things working right in every app.

Ubuntu Studio 20.10 (0-48 low latency) has a LOT of latency and some problems.

Best config for my harware is:

"hw:VSL,0" (to put in app Alsa parameters if needed - Phasex needed it to use Jack driver, although worked with previous Alsa driver)
in Studio Controls: Jack master / USB that should be Master: VSL / a2jmidid turned ON / 44.1 kHz, 1024 buffer & period of 2.
Jack needs to be running. My USB device has been put in the Device Blacklist, and on every session startup, I have to manually change the Performance and Boost OFF settings. There must be something wrong somewhere...

Checked on Alsa website, my card is not supported. Could I use Jack only? Seems not, if I turn a2jmidid I get no midi input... this is hard to figure out!
I think I need Alsa backend, the other option is Dummy and everything disappears in Studio Controls for Master Device.

I can use Jack pretty much everywhere (Yoshimi for instance) and sound is good in MuseScore and Hydrogen, but still have high latency in Ardour6.3 and struggling with Phasex (can configure Jack driver right in preferences, but can't save the configuration file).

Carla still can't get MDI input from my keyboard to play (ex. LV2 sound Foo YC20: I can hear the virtual keyboard play, the patchbay has MIDI input connected to it and the module ouput to Audio output , but I get "kf.kio.widgets.kdirmodel: protocol mismatch: "" vs "file"" when I try to save the project). Doesn't work in Ardour either, nor in Qtractor (probably not going to use it anyway, but I get only error messages).

The help from Phasex mentions if Qjackctl is not properly configured, it will always revert to Alsa, so I'd like to fix that first in order to save Alternate configuration ( with console command "phasex - c -- 'what do I need to enter here as argument?'" ?)

I opened Qjackctl GUI and am trying to understand how settings work:
Connect has the Audio output section: Pulse Out, but has microphone icons, and the input section has speakers icons, seems odd...
The MIDI and Alsa in that section seem ok.

Sorry, my system's in french, can't translate: "Baie de brassage" has nothing in it.
Tried adding a New config and the same inversion is there if a take a snapshot of actual connections ("cliché de toutes les connexions clientes actuelles"). So I left it blanck for now.

Fiddled just now with Qjackctl / Setup and selected interface "hw:VSL,0", set period to 2, but I don't know what to put for other options (MIDI driver is "none", seems ok, and I noticed in the Options tab I could make the Bay persist (maybe that would get my config of Studio Controls permanent)).

Didn't change Carla (I probably still have to configure it right too, just after my Qjackctl config is done).

There probably should be something in Bay, but since my config seems not totally right, I'd like some factual info on what settings to use. Hard to find on Google: only links about download or older versions (mine is Qt 5.14.2 and Qjackctl 0.5.0 - maybe it's a version mismatch problem).

Thanks for any help or useful links about it (english or french, doesn't matter).
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