Carlos,

When I've used X2 chords, the 3rd is usually played and the 2nd is usually played above the 3rd (i.e. as an added 9th). My understanding is that BIAB and RB interpret X2 as Xadd9 (not as a sus 2 where the 2nd is used in place of the 3rd).

To confirm this, I have just added C2 and watched the keyboard telling me what notes were being played. For the majority of the chords in the piano part the notes were: bass = C, chord = E-G-D. This is one way in which a pianist would play Cadd9.

Just my 2 cents worth!
Noel


MY SONGS...
Audiophile BIAB 2025