Hi John, Not sure what you mean! BUT, Standard setup for midi accordion is,

Right voice = Channel 1
Cords = Channel 2
Bass = Channel 3

I no longer have my SD40, but when I did I used this method. From my Roland FR-8X I always set the Bass and Chords on the same channel. Channel 2 Works fine!

In this way I am able to make extended chords such as Maj7, m7-5,
m7, 7-9, ETC

I'm using this same setup with my Yamaha Genos. Works great!
Don P