I can buy that, and actually thought of that as a reason - for later, but in this case it is the same chip. I have it set up on my breadboard and just reprogrammed it with each of the two programs. So all components are the same in both cases.

In doing a bit more fiddling with it I noticed that a little routine used elsewhere that involves a bit of assembly code to drvie the speaker works the same if used in both programs so it still seems to be revolving around the actual SOUND command.

I have swapped the program a couple times and each time the sound has changed so it isn't just one of those weird one time things.

It really has my head going since I managed to write a program that worked as intended in every other way. The sound thing will keep me awake!

Bart