The Mixing Voice allows you to tweak a Voice exclusively for the current Song or Pattern Mixing setup in the keyboard Motif XS. A Voice stored in the normal User Bank, is accessible by any and all Multi setups. A Voice stored in the Mixing Voice is actually stored with the Song or Pattern data, and is only available in the Song or Pattern Mixing program in which you created it.

The significance of this becomes clear when you want to load a single Song, or a single Pattern from a file. If you used the User Bank to store your edited Voices, you must ensure the correct User Bank data is in place. If, however, you stored your edited Voices in a Mixing Voice location, when load the individual Song or Pattern, your edited version loads as well.

Overall there are 256 MIXING VOICE locations total for the XS. The advantage is when you've customized a Voice for use in a particular composition, you can store the normal Voice data so that that data in included if and when you load the Song or Pattern individually! Very useful when assembling Songs or Patterns from a variety of files.