Originellement posté par MarioD
Maybe this will help, see pic.
{edit} - there is a good explanation of MIDI local control settings starting on page 196 of your manual.

Originellement posté par Jim Fogle
The Yamaha CVP-307 shares manuals with the CVP-309. Manuals are available from Yamaha +++ HERE +++ . You may want to download the user manual and look at pages 196 - 200.
Here is part of what the manual says about local control:
Citation
Turns the Local Control for each part on or off. When Local Control is set to “ON,” the keyboard of the instrument controls its own (local) internal tone generator, allowing the internal voices to be played directly from the keyboard. If you set Local to “OFF,” the keyboard and controllers are internally disconnected from the instrument’s tone generator section so that no sound is output when you play the keyboard or use the controllers.
Notice local control has multiple parts.

Thanks MarioD and Jim Fogle,

I'm not called Lazy Bird for nothing: I've had the manual for my Clavinova CVP 307 for years, and it's only now, on your advice, that I'm starting to delve into it to understand a little better how MIDI works ;-)!

Andrew (PG Music) privately told me how to do a comprehensive test of my piano's MIDI settings, and I'm going to give it a try. It'll take some time, but I'll share the results as soon as I'm done.

Best!

Lazy Bird