It is the new AiX sound engine. My privia has the AiR sound engine. About the sound engine, Some sounds are not that good out of the box but as soon you start editing the sounds you will be amazed what you can achieve. Same for the styles. Also the Mz x 500/300 have much improved after the updates.

As a singer first lead voices don't concern me too much as they are all up to par for accompaniment and solos for a singer/player. It amazes me how little people use sounds anyway in their performance demos songs...mostly I hear lead piano, but not alot of changing instrument lead sounds thru-out the song which gets boring to the listener imo...

I could not agree more and have already written about it in several of my reflections. Nearly all of those who actually sing and use their arranger as a backup band will use very few different sounds for their right hand than piano, guitars, sax, brass and the occasional accordeon or other sound.

The quest for more and more sounds is pretty absurd unless you want to become a 21st century Jean Michel Jarre or perhaps another New Age guru (haha !!) which brings me to re-iterate what I said before:
If you are a singer your first choice will be the PA4X or SD9 and if those are too expensive the PA1000 or SD7 will be a very worth while second choice imho.
If you only perform instrumentally , either at home or on stage, my first choice would be Genos or otherwise a used Tyros or the new PSR 975. Enough said.............

regards
JOhn

When it comes to some instrumental only players, I've heard some people play a different lead voice on every flippin' verse. That just grates on me.

That's interesting ... if you were listening to a band play, wouldn't different instruments play on different verses? ... or is it that with each voice that's being used the melody is exactly the same ... that situation gets to ME ... I'm short on my music theory and chord structure/substitution and harmonies, but I can do a fairly competent job of taking an ad-lib solo around the basic chord structure of the song so it sounds somewhat different when using a different voice ...

Speaking about Launch Pads I’m confused. First, it seems that Ketron leaves an explanation part to enthusiasts, or did I just miss an official video?

Second, it’s not clear, how can wave files be suitable for accompaniment, there’re just too many possible chords to follow.

Forgive me for skepticism (ignorance), but is it really more than just taking advantage of the fact that memory is very cheap today and it doesn’t take much thinking to put a lot of wave samples into a keyboard? By the way, Dexibell is also about audio accompaniment, and I’m skeptical and ignorant about that as well.