I'll start by saying that, without being an ace, my accordion playing is pretty good. (piano key) I can reproduce several songs by Tiersen, Les Têtes Raides, or La Rue Ketanou. Anyway, while trying to improvise with my keyboards, I discovered that you could play a bit of melody with the basses and counter basses.
I realized, for example, that the 2 basses of the C chord were C and E. Could you find me the other notes of the basses and contrabasses, or direct me to a site that explains it all... Thank you all... and musically yours.