Hi konaboy,
• first of all, you could use a Volume Pedal (FC7). I recommend setting the Pedal so that only the RIGHT parts are affected. (If you want, you can also include the LEFT part.) Connect the Pedal to the switched OFF keyboard and then power ON. Now, press [Direct Access] button and press (turn) the pedal a little. This will open the display where you can make the Pedal settings. Save your customized Pedal settings at least in one so called "Setup Registration" (or save the desired Pedal settings with ALL Registrations).
Then you can easily control the Volume of the Keyboard Parts while playing, while keeping the Style and Multi Pad Volume levels unchanged. (If the Volume Pedal (FC7) is fully depressed, the affected Parts will have the same Volume as when the Pedal is NOT connected.)
• OTS do NOT change the STYLE Volume. So, you can simply increase the global STYLE Volume a little (in the MIXER display) if you think the RIGHT Voices are "too loud" when using the OTS.
• In principle, I recommend to create your own REGISTRATIONS and then play with them (instead of playing with the Preset OTS). You could also adjust the Keyboard Voice settings (Right 1/2, Left) and memorize it back to the OTS buttons. But then you have to newly save the STYLE, because the OTS are part of the Style data.
• You can also use a Live Controller knob. Assign one of the following functions to the desired knob:
Keyboard Volume:
Adjusts the volume of all keyboard parts. This is convenient for adjusting the
volume of all keyboard parts together for optimum balance with the others
(MIDI Song, Style, Multi Pads, etc.).
Volume:
Adjusts the volume of the selected parts or channels.
Select Right 1/2 and possibly Left here, OR select Style.
Balance:
Adjusts the volume balance between parts A and B. You can select which parts belong to
A or B in the pop-up window called up via [Balance Setting] at the bottom of this display.
(For example select Style for "Part A" and Right 1/2 for "Part B".)
Please refer also to SX900/700 Reference Manual, starting on page 117.
Hope this helps!
Best regards,
Chris