You can also use the Makeup Tools to mute as many parts as you’d like in a style or SMF, so you can practice either on piano, or leave the piano comp in and work on a solo sound like sax or guitar, whatever.
I can’t remember off the top of my head, did the E80 also have the ‘track Mute’ button that the BK series does? It allows you to define (sadly, only globally, not per UPG/Performance) which channels get muted, so if you are using professional SMF’s like Tune1000, which had well defined channel #’s for each sound (bass, piano, guitars etc), you can easily mute a particular Part each time.
BTW, you can also bring up the Makeup Tools visual mixer page, and if you tap the icon at the top of each sound, it instantly mutes the sound. Very handy!
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An arranger is just a tool. What matters is what you build with it..!