Hi Shadowrieger,

I checked out the PSR550 manual on the web, and it looks like my description should work . The PSR has a Midi IN /out port, You can set it to "RECEIVE CHORDS", and I think it had a chord "detect" ability. So you should try to find the right settings to have the PSR receive and detect chords. You will need a MIDI wire from the computer to the keyboard,(I use Yamahas UX16 cable- USB to Midi), and the appropriate driver so that you are useing the keyboard sound making features, NOT the computer sound card.

The BIAB should be set up like my video described. Both the computer and the keybord set ups are a bit tricky, so you may have to use a bit of "trial and error" to make sure all the buttons that should be activated are pressed, and all the buttons that should be off are turned off.

Give it a try, and if you need additional help, get back to me.
Good Luck

Rocco