qsynth is a qt fluid synth front end. It's a midi piano program to make sounds.
root # emerge qsynth fluid-soundfont
sound fonts are located: /usr/share/sounds/sf2/FluidR3_GS.sf2 /usr/share/sounds/sf2/FluidR3_GM.sf2
start qsynth as root setup > midi tab > midi driver > alsa_seq setup > audio tab > audio driver > jack setup > soundfonts tab > open > load in /usr/share/sounds/sf2/FluidR3_GM.sf2
restart qsynth as root, connect keyboard via qjackctl connect dialogs, and you're ready to play.
the channels button is where you configure what sound font bank is playing, and on which channel. ie piano channel 1 harpsichord channel 2.
as this is an audio program we wish to enable real time priorities:
root #echo "@audio - rtprio 99" >> /etc/security/limits.conf