The RSP-550 offers the ability to control four parameters per Patch in real time using MIDI. The parameters available differ depending upon the algorithm. This feature can be exceptionally expressive in both a live setting and when used for automated mixing in a MIDI sequencing environment. Use the following procedure to experiment with real time MIDI control:

1. Use the PROGRAM buttons to select "Patch 193 / - - - Multi 1 - - - ."
2. Press the CONTROL ASSIGN button to select "[Ext. Control / - l - l - l - ]." Solid numbers have controllers assigned, flashing numbers do not have controllers assigned.
3. Use the PROGRAM buttons to select one of the external controllers and use the VALUE buttons to turn the external controller on or off. Turn the 1st external controller on so that we can program a realtime controller.
4. Select external controller number 1, turn it on, and press the CONTROL ASSIGN button. The screen will display "[Control Source / Control SW]."
5. The Control Switch is the footswitch that is on the back of the unit. If you want to set a different controller, use the VALUE buttons to select a new control source. Controller #16 is a common choice for realtime effects control.
6. Press the VALUE UP button several times to display "Control Source / Control #016."
7. Press the PROGRAM UP button one time and use the VALUE buttons to select the individual effect parameter that you will be altering.
8. Press the PROGRAM UP button once.
9. Use the VALUE buttons to set the Minimum level to 0%.
10. Press the PROGRAM UP button.
11. Use the VALUE buttons to set the Minimum level to 50%.
12. To save these settings, press WRITE, use the VALUE buttons to select the desired destination, and press WRITE again. If you do not want to save these settings, skip this step.
13. Press EXIT to return to the play mode.