Optimising_Linux_For_Audio

See e.g. this article on opensource.com. TLDR:

sudo apt-get linux-lowlatency jackd2

high priority (realtime) for e.g. Reaper and Renoise.

sudo setcap 'cap_sys_nice=eip' /usr/local/bin/renoise-3.4.2 
sudo setcap 'cap_sys_nice=eip' /opt/REAPER/reaper

and CPU governor to performance:

echo -n performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

See this FAQ on Pulseaudio and Jack ([[Pulseaudio]] is the desktop Linux sound-server used by everything except low latency audio apps. We want jackd to manage the audio hardware, and Pulseaudio to go the hardware via jackd.)

limits.conf

 @audio - rtprio 90       # maximum realtime priority
 @audio - memlock unlimited  # maximum locked-in-memory address space (KB)

(source: linuxaudio.org)

Jack stuff

Use Cadence

Old

We want to route ALSA to Pulseaudio, and Pulseaudio to Jack.

sudo apt-get install pulseaudio-module-jack

then ~/.config/pulse/default.pa:

load-module module-native-protocol-unix
load-module module-jack-sink channels=2
load-module module-jack-source channels=2
load-module module-null-sink
load-module module-stream-restore
load-module module-rescue-streams
load-module module-always-sink
load-module module-suspend-on-idle
set-default-sink jack_out
set-default-source jack_in

and possibly in ~/.config/pulse/daemon.conf:

default-sample-format = float32le
default-sample-rate = 48000
realtime-scheduling = yes
exit-idle-time = -1

and if using qjackctl as the launcher, in settings, add the following post-startup script

pactl load-module module-jack-sink channels=2; pactl load-module module-jack-source channels=2; pacmd set-default-sink jack_out