[Jack-Devel] Jack Problems

[Holger Marzen]

On Tue, 26 Mar 2019, liebrecht at grossmann-venter.com wrote:

> I have to killall -KILL jack and especially qjackctl a couple of times until I
> get jack to start with qjackctl. It seems jack starts as I see it as a process
> but qjackctl falsely reports it as not being started. After a few kills it
> eventually sees it.
> I will just start jack with a string as I did in the past and drop the qjack
> thing, but for now I will try and use it.

There might be a program that starts jackd when logging in. That could
even by Pulseaudio when playing some system sounds. The script I posted
here makes a "clean table" by killing everything that might get in the
way.

> I can confirm that I get sound out to the 1818VSL by using a Synthesizer organ
> app.
> SetBfree.

Great. So jackd works and Mixbus' behaviour is the problem.

> I can play keys and it is passed to the 1818vsl, however I have no functional
> global volume controls as my keyboard mappings are not recognized by jack or
> whatever now handles the mappings.
> Its all raw maximum volume.

Yep. Jackd has no master volume. I once suggested adding it but no-one
was interested. There are several workarounds:

- If the audio interface has a software controllable mixer, use alsamixer
- Use jack-mixer and set up jack-plumbing to disconnect every
  application from system:out and connect it to one of jack-mixer's
  inputs. Of course it should connect jack-mixer's outputs to
  system:out.

> The output from qjackctl seems to indicate that setbfree uses jack.
> 02:47:49.435 JACK connection change.
> 02:47:49.752 JACK connection graph change.
> Destination port in attempted (dis)connection of setBfree DSP Tonewheel
> Organ:control and system:midi_capture_1 is not an input port
> 
> So does jack even have a mixer of some sort so I dont have to blow the walls
> down with the default settings as it is now.?

No. But you can connect your apps to a mixer like jack-mixer as I
described above or use alsamixer.