jackd
TLDR
Start JACK with ALSA driver
$ jackd -d alsa
Specify sample rate and buffer$ jackd -d alsa -r [48000] -p [256]
Start in realtime mode$ jackd -R -d alsa
Use specific device$ jackd -d alsa -d [hw:0]
Start with verbose output$ jackd -v -d alsa
SYNOPSIS
jackd [options] -d driver [driver-options]
DESCRIPTION
jackd is the JACK audio server daemon. It provides low-latency audio connections between applications with sample-accurate synchronization.
JACK is essential for professional audio on Linux, enabling complex routing between DAWs, synthesizers, effects, and hardware.
PARAMETERS
-d driver
Audio driver (alsa, coreaudio, dummy).-R, --realtime
Use realtime scheduling.-r rate
Sample rate (44100, 48000, etc.).-p frames
Frames per period (buffer size).-n periods
Number of periods.-P
Playback only.-C
Capture only.-v, --verbose
Verbose output.-T, --temporary
Exit when all clients disconnect.
DRIVER OPTIONS (ALSA)
-d device
ALSA device (hw:0, hw:1).-S
Force 16-bit samples.-H
Hardware monitoring.
CAVEATS
Requires realtime privileges for low latency. Buffer size affects latency vs. stability. Consider JACK2 (jackdbus) for modern systems.
HISTORY
JACK was created primarily by Paul Davis starting in 2002. It became the standard for professional audio on Linux, enabling pro audio workflows comparable to commercial systems.
SEE ALSO
jack_connect(1), qjackctl(1), pulseaudio(1)
