Could you not get triads on the h9? The was an arpeggiator and a multi tone pitch flex (quadrivox?)
There are many algorithms where generating triads are possible on both the H9 and H90. Most algorithms give you the ability to add two (Diatonic, H910/H949) and up to four notes (QuadraVox) on top of the root note. You’re able to choose intervals that will create triads and also in key.
