slackbuilds/audio/qjackctl/README

qjackctl (Qt application to control the JACK sound server)

Provides a simple GUI dialog for setting several JACK daemon
parameters, which are properly saved between sessions, and a way
control of the status of the audio server daemon. With time, this
primordial interface has become richer by including a enhanced
patchbay and connection control features.

Note: This package optionally uses POSIX filesystem capabilities
to execute with elevated privileges (required for realtime audio
processing). This may be considered a security/stability risk. Please
read http://www.slackbuilds.org/caps/ for more information. To enable
capabilities, pass SETCAP=yes to the script.

Optional dependency: portaudio