Don,

I am not entiorely positive, as I got my harmonizer after I updated the OS in my PA80 don't think that OS 3.1 did anything to change the way the harmonizer works. I have to say though, that I find the harmonizer in the PA80 to my liking. I've had to change a the way I approach my setups and performances now that I have it, but even my staunchest critic ( the wife of course.. who else ? ), says that when she hears me sing with ( and without it ) into my current setup ( SM58 directly to the PA80 ), that it is the best she has ever heard me sound. Who am I to argue with THAT?? lol

Korg AJ