JACK

This article Article description::describes the setup of a playing sound with JACK (JACK Audio Connection Kit).

JACK is a sound server where applications like mpv can connect to to play their sound.

Installation
JACK uses ALSA for accessing the sound card hardware, be sure ALSA is working.

There are two implementations of JACK, both implementations are considered equivalent. JACK is the original implementation, it uses a C API and has built-in Linux MIDI integration. Whereas JACK2 was rewritten in C++ and has support for SMP and DBUS.

Visit "what are the differences between JACK 1 and JACK2" for an in-depth comparison.

JACK2
First, emerge the sound server itself.

USE flag
The global USE flag  enables support for JACK in other packages, so they can submit sound to a JACK server:

The command is part of.

After setting this be sure to update the system so the changes take effect:

Sound Server
A good JACK configuration and control software is.

Bridging
JACK can route sound which was sent to other sound systems like PulseAudio and ALSA through itself.