via http://psp.dashhacks.com/2012/01/24/tonematrix-07

If you are a musician or a producer of music such as myself then this piece of [COLOR=blue !important][COLOR=blue !important]PSP[/COLOR][/COLOR] homebrew will keep you entertained for a fair long time.
-Hacks forum member Babkock has thrown down ToneMatrix 0.7, a homebrew [COLOR=blue !important][COLOR=blue !important]app[/COLOR][/COLOR] allowing you to create your own music loop through the use of 8 different sounds and 16 possible places to set each
The latest update (0.7) allows you to mute desired tracks by pressing square, turning that track red. If you wish to play one track as solo, place the cursor on that track, press triangle, and all other tracks turn blue.
Download the unsigned homebrew and leave some feedback on the thread below!

http://forums.dashhacks.com/psp-home...rix-0-7-a.html