On my PSR3000 I have embedded SysEx on a couple of midi files to call up delay-line or heavy distortion effects blocks. I worked out the hex by hand, but then again I'm a computer geek by profession!

Trouble is I use the registration memory to call up suitable keyboard voices and sometimes the registration setting nukes the FX parameters set up for the song which is playing.

I think this is to do with the FX associated with the voices.

To stop this happenning I now have the "Freeze" button selected almost permanently and I can't say I've noticed any deterioration in the quality of the voices that I play on the keyboard.