Use PulseAudio with Jack Audio Connection Kit?
Ubuntu Studio 14.04 uses Pulseaudio -> Alsa -> Jack as the connection interface for audio devices. Pulseaudio is a very simple interface, and with it most audio cards just “show up” and play with Jack as the pulseaudio-sink and pulseaudio-source devices on the Jack patchbay.
In the olden days (Ubuntu Studio 10.04 and before) Pulseaudio was buggy and not worth the effort to deal with the bugs. Pulseaudio is now much more mature, and for a single sound card machine makes it much more likely that you will have Jack working right away. If you are using Debian or regular Ubuntu, you will need a Pulseaudio plugin to hook it up with Jack. I have not used the plugin as it is all nicely done in Ubuntu Studio.
Alsa is perfectly capable of connecting sound cards to Jack, with infinitely more flexibility, and (unfortunately) with more complexity. Remember to turn the volume controls up in alsamixer!
There still remain some reasons to dump Pulseaudio:
- Pulseaudio works best with a single sound card – if you have an in-computer card and a USB card and want to use both, Pulseaudio is complicated at least and may not let you use the second card. (I have not been successful, but I didn’t try very hard)
- Pulseaudio devices want to hook up to stuff in the patchbay, and I have not figured how to keep them from automatically doing so.
- Pulseaudio adds latency to the audio chain. If you are just recording and playing back stuff and “real time” audio is not important, this might be insignificant.
- Pulseaudio and Rivendell get in the way of each other. Rivendell wants to have multiple audio inputs and multiple outputs, and that can be a problem with Pulseaudio if they are on different cards.
- Pulseaudio devices Pulseaudio-sink and Pulseaudio-source hide the names of the actual sound devices, so they can be confusing when patching.
- Pulseaudio hides and plays with some sound card settings in Alsa, so special configurations might just get reset to the defaults at next boot.
The reasons to keep Pulseaudio:
- Alsa can be tricky to get all your audio devices working right unless you are happy to use the command line.
- Ubuntu Studio comes with Pulseaudio installed and working, and dumping it can cause your installation to stop working until you figure out what Alsa settings for your sound card are undone.
- There are some tricks to getting Pulseaudio to uninstall or to disable it. (It keeps coming back)
- Pulseaudio now keeps a simple setup simple (except for those crazy patchbay devices)
Assuming you want to remove Pulseaudio, here is what you do:
sudo apt-get -y autoremove pulseaudio
2. Now do a reboot since PulseAudio daemon (system service) is also running from the background. So it’s better to let the OS update everything.
3. You need the package alsa-tools, but that is already installed in Ubuntu-Studio, but not in regular Ubuntu.
4. The script I will be publishing later will do this all automagically.
If you just want to just disable PulseAudio, you can edit the config file
1. Copy /etc/pulseaudio/client.conf for a backup
sudo cp /etc/pulseaudio/client.conf /etc/pulseaudio/client.conf.orig
2. Modify /etc/pulse/client.conf the line ; autospawn = yes to autospawn=np
sudo sed s/; autospawn = yes/autospawn = no/ /etc/pulseaudio/client.conf
3. Reboot or kill the pulseaudio job.