Hi Jim. I'll bet you're going to flip when you read my answer.

First, to make sure, some basics:

Let's say that a C chord (C Major) is spelled C,E,G going up from the root, C.

Then a C2 would be spelled C,D,E,G.

The number '2' comes from the count up the major scale: C is 1, D is 2, E is 3 etc.

It is much the same as a variant, Cadd9 which is C,E,G,D or in other words, the same notes as C2 but where the D is voiced (played) up an octave.

9 and 2 are both the pitch of D (in the key of C), because in any upper extension chord, the number 7 may be subtracted to get the same tone. So the pitch of a 9 is the same as a 2 (just up an octave); the pitch of an 11 is the same as a 4 up; the 13 same as 6.

Make sense?

X2 is a very nice chord in folk music. Guitarists often play that in fingerpicking for interest and fullness. Would that I could do it.

Probably you already knew all that. But BIAB plays a 2 chord the same as an add9. They can sound the same. Whichever octave the D plays on is determined by the program's voice leading and some other magic under the hood.

And if you want to look under the hood, here is how I know what BIAB is doing: the file, /BB/pgshortc.txt

PG Music treats all these chord types as a '2' chord: 2, add2, add9, and sus2! So, about the original wish to control inversions, on these four chords it doesn't matter! You hear the inversion the program (player, in the case of RealTracks) thinks best in the context of the chord progression.

Still with me?

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.