[PlanetCCRMA] Pulseaudio and qjackctl

Rui Nuno Capela rncbc at rncbc.org
Wed May 6 15:44:28 PDT 2009

Jeff Sandys wrote:
> I am testing Fedora 11, and I got qjackctl to work fine, but I think the
> configuration isn't right.  Here is the part of the note I posted to Fedora
> Forums:  I saw that Fernando weighed in on the Pulseaudio ALSA debate.
> I installed qjackctl on a Live-Preview-XFCE-i686 usb with persistence.
> In the qjackctl connect panel there were no audio output or input ports
> until I installed pulseaudio-module-jack and alsa-plugins-jack per Harald
> Hoyer's Pulseaudio and Jackd tips, (jack-audio-connection-kit was installed
> with qjackctl).
> http://www.harald-hoyer.de/linux/pulseaudio-and-jackd
> I added "liveuser" to pulse-rt and jackuser and noticed that
> /etc/security/limits.conf already had jackuser and pulse-rt added.
> Should pulseaudio-module-jack and/or alsa-plugins-jack be a dependency of
> qjackctl?
> I couldn't get my usb MIDI keyboard working, there were no midi or alsa
> output or input ports in qjackctl connect, and jack complained about not
> finding an ALSA midi seqencer when it started, until i did a modprobe
> snd-seq-oss. What is the default /dev/sequencer?
> Should modprode snd-seq-oss (or equivelent) be part of the standard
> distribution?
> After that qjackctl ran fine, I didn't have to stop pulseaudio to start jack
> or use any of the other suggestions in Harald's tips. I pounded on zyn for a
> while with jackd -R -r44100 -p250 -n2 with no xruns and about 10% usage.
> The XFCE panel volume control lets you select between Pulseaudio and the
> audio card, I had to switch to the card and set the PCM to 100% to get
> sound. This is a nice feature.
> What is the proper was to set up midi with jack so that the midi connectiosn
> show up on the MIDI tab instead of the ALSA tab?  
> Any other pointers to the correct modern linux audio setup is appreciated.

the ALSA tab shows ALSA sequencer MIDI client/ports connections

the MIDI tab shows JACK MIDI client/ports connections

ALSA sequencer support is present on qjackctl OOTB as convenience; you
can turn that off from Setup/Misc/Enable ALSA Sequencer support, making
qjackctl a *pure* JACK (Audio and MIDI) control panel and rid of nagging
warnings about ALSA sequencer module not being loaded (snd-seq-midi)
anymore--you'll probably miss your USB MIDI keyboard though ;)

rncbc aka Rui Nuno Capela
rncbc at rncbc.org

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