I have a Yam psr 8000. When you create a "custom" style, you select a "root" chord to play with.A certain page in the manual lists all the chords and scale notes you can use.

This a limiting factor. You can't just punch in any old bass riff, no matter which chord you use.

Back in the day Technics boards, however, would let you do exactly that.

But they are no more.

Is there a board (other than current Motif...I was thinking "arranger')nowadays that will do this?