What is it?
Mixes all of the tracks in the sound document down to one track.

How to use it
All of the mixer settings (Solo, Mute, x2, Volume) are used, so it sounds exactly the same as it did before mixing down.

Notes  
"Mix Down To Mono" is for mixing sounds within a single sound document.  Use the "Mix" envelope for mixing sounds in separate sound documents.

If you get strange results, try "Inverting" some of the tracks before mixing down.  This should eliminate any cancellation problems caused by mixing similar sounds 180 degrees out of phase.