from euroguy213:

I was messing around with the 3.90 m33 music prx and noticed that it contained a file called audio_id that was over 800mb in size. in the file the same 50 lines were being repeated over and over again. after i deleted all the repeated lines i was left with a file size of 108kb. the prx works on 3.90 m33 and 4.01m33-2 slim and phat psps.one of the only bugs is that in game mute doesnt work.

here are the controls for the plugin
VOLUP = NOTE|UP
VOLDOWN = NOTE|DOWN
START_STOP = NOTE|START
PREVIOUS = NOTE|LEFT
NEXT = NOTE|RIGHT
MODE_TOGGLE = NOTE|RTRIGGER #SEQ/RAND
CPU_NEXT = NOTE|TRIANGLE
CPU_PREV = NOTE|CROSS
RELOAD = NOTE|CIRCLE
DISPLAY = NOTE|SQUARE #on screen display
IN_GAME_MUTE = NOTE|HOME #press this combo once to disable game sounds, and again to enable them
LOOP = NOTE|LTRIGGER

***You must hold the note button and press up, down,x,triangle.....***
***If you dont like the controls you can edit them in music_conf.txt in the seplugins folder***

credits for the original prx: Cpasjuste