Normal Voices have 8 Elements (oscillators).
Drum Kit Voices have 73 Elements (oscillators).

Each Element is a complete entity.. And has its own Pitch, tuning, pan position, volume, filters, envelopes, routing to effects, routing to outputs etc., etc., etc.

Drum Kit Voices are simply too large, too complex, to be stored as MixVoices, that function does not exist for Drum Kit Voices, not in the ES, not in the XS, XF and definitely not in the W7 (yes, I remember that as well). The whole Mix Voice concept for storing edited versions of Voices locally in the Song/Pattern Mixing setup (256 locations total) was introduced in 2003 in your Motif ES.. As a method to allow users to store especially edited Normal Voices with the Song or Pattern. Making it easier to combine (assemble) Songs and Patterns built from different Voice libraries.

Drum Kits must be stored in one of the 32 Drum Kit Bank locations.
Thirty-two 73-piece drum kits is more than any drummer I know ever owned.

Thanx Bad Mister for such a fast reply ! I asked because I accidentally lost an edited kit in UDR when loading in something else (an Oriental KIt played instead of mine which produced interesting results !). Luckily I always backup my backups so all was recovered easily.

Kind regards

Sorry to be a pain Bad Mister, but did the W7 have a SD (Song Drum) memory location - in effect what I guess we would call now Mix Drums ? Don't wanna go off-topic in an XF forum (or question your knowledge ! ). I still remember seeing you on the tutorial video that came with the synth (VHS - remember those !! ) .

Bye

"Song Drum", Ah, yes. Those were the days.

Sorry, what got adopted (in subsequent keyboards) was 32 USER DRUM KITs that has proven to be more than most people ever need. They kind of just stay anchored in their User Drum Bank location and are recalled as necessary.