horgand is a softsynth, really simple and easy to use, specially designed
to produce organ sounds, and is also capable of generating other sound
types like Electric Pianos, Jazz Guitar, Strings, Brass, Fretless Bass,
Accordion etc. using low CPU resources.

This requires fltk and jack-audio-connection-kit.

This package 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 disable
capabilities, pass SETCAP=no to the script.