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Newbie 3.0.0 Question -I Don't Know Jack (audio server)

Posted: Mon Apr 19, 2021 8:04 pm
by the_yipper
I am running Ubuntu with a 5.4.0-72 low-latency kernel.
I got the kernel recently when I was trying to switch to Ubuntu "Studio"
It looks like what Ubuntu Studio is, is a link to a repository that serves a ton of audio/video applications. There is now a ton of such things in my application menu..
I want to see if I can use Jack with audacity to hopefully benefit from the low latency kernel. My latency compensation is 138 milliseconds now, through a Blue Snoball usb mic...
Ardour5 came with the "studio" and uses Jack (maybe by default) but I'm not ready to try to learn a whole new DAW when I like audacity a lot.
I downloaded the "minsrc" tar file for audacity 3.0, and it is sitting in my home directory.
Now, can/should I use <apt -install audacity> or something to install audacity (I can worry about the jack server later) so that I will have the latest one that saves projects in the new format? I have read not to use flatpak and snap versions -plus those two put competing icons in my app menu...
I just want to have the latest audacity; I guess by downloading the tarball and unzipping it; I now just need an installer of some kind? If I don't want to build it using Cmake,and all that....
Thanks in advance.

Re: Newbie 3.0.0 Question -I Don't Know Jack (audio server)

Posted: Mon Apr 19, 2021 8:34 pm
by steve
the_yipper wrote:
Mon Apr 19, 2021 8:04 pm
Ardour5 came with the "studio" and uses Jack
Is that working? (are you able to load an audio file and play it with Ardour using Jack)

That's to prove if Jack is working correctly. If it is, then installing Audacity and running it with Jack should be straightforward.

I would NOT recommend using Audacity 3.x yet.
The latest version of Audacity is 3.0.2 (released this morning) and there are no pre-built packages yet. Building from source is not difficult, but requires setting up a build environment (installing several other packages).

Much easier to use the official repository version of Audacity (a little bit older, but it can update automatically when updates are available)

1. Install Audacity from the Ubuntu repository

Code: Select all

sudo apt install audacity
2. Ensure that Jack is running (it may be configured to run on log-in, otherwise start it with QjackCtl)

3. Launch Audacity

4. Select "Jack Audio System" as the "host" in the Device Toolbar.

5. Restart Audacity.

Re: Newbie 3.0.0 Question -I Don't Know Jack (audio server)

Posted: Tue Apr 20, 2021 10:24 pm
by the_yipper
Thank you so much...
I don't think Jack is connected at login -although I read that this gives superuser privileges to the person logging in, so as to use the "real-time" (kernel level, I guess) functionality; something to do with having priority over the audio bus in real time, without being interrupted.
I don't think it starts because that same device menu in Audacity doesn't show Jack as an option. I seem to recall on another system that had it running, there being a choice between Jack and ALSA...
But, yeah, opening up Ardour5 and loading a file would test Jack, I had only been hesitating because it seemed to involve starting it when the system booted and I didn't want it to interfere with other apps like SMPlayer, or even Youtube that might be configured to use "system default" which might be registered as Pulse or something; then I would have to go manually through my applications and configure them to use Jack...if that doesn't expose me as the newbie I am.
Once I start using Jack, then I will have to get it running before playing/recording music that same night.
Do you know if the "low-latency" kernel is going to help audacity, or allow me to use software play through when monitoring as I record?
Thanks again. I'll try to put Jack on using Jack Ctl, then see if it then appears in the device menu in Audacity. Maybe I can make it the system default from there, too, and not have to worry about other applications suddenly having no sound, LOL

Re: Newbie 3.0.0 Question -I Don't Know Jack (audio server)

Posted: Tue Apr 20, 2021 10:56 pm
by steve
Do you actually need to use Jack? If not, then don't.

Re: Newbie 3.0.0 Question -I Don't Know Jack (audio server)

Posted: Wed Apr 21, 2021 3:12 pm
by Neil Darlow
@the_yipper Realtime privileges may be assigned to group Audio when installing (or reconfiguring with dpkg-reconfigure) the jackd2 package. You must add your login user to group Audio in order to use realtime privileges in JACK.

JACKd isn't automatically started at login and, as steve suggested, QjackCtl is the preferred method to configure and control JACK for use with jack-enabled applications like Audacity. You will need to set devices for JACK to use and you can adjust the realtime priority used.

The use of Audacity in flatpak format won't help because the flatpak application is unable to communicate with JACKd.

ATB,
Neil