F5 Key Change option that works for transposition

Songs often modulate, whether it just two measures of a ii – V – I in another key, or an eight-bar bridge, or a final chorus that is higher than the rest. If you are only working in concert pitch in BiaB then you will be able to type in the chords that are correct for each of the modulations, and you also have the option of changing the key signature at any measure (except the first). The problem comes when you try to transpose the song. BiaB will base the chord roots for the whole piece on the key the song starts in. For instance, say you have a song that modulates up a half step, and you transpose the song or the notation so that it begins on Bb. The second section should now be in the key of B, but because the first key in the song was a flat key, all the chords that ought to start on sharps in B will start on flats instead.

I would like a way to keep the chords diatonic to the new key. I.e., In B major: B C#min, D#min, E, F#7, G#min, A#minb5. And I also want the notes in the new key to be written in the new key signature, not as enharmonics.

My proposal is for you to replace the “Key Signature Change To” feature in the F5 menu with a revised version that will work for transposing. Here are my suggestions for the proposed feature to replace it.

1. Call it “Key change to”, and, to make it more useful for brief “key of the moment” modulations, have a check box for “Change key signature”, which should be checked by default. Unchecking it should not affect the way chords and notes are chosen compared to keeping it checked, but would only affect whether accidentals are needed in the notation.
2. The key changes marked by using this feature would be transposed when the song is transposed.
3. Chord roots, starting at this point, should be named based on scale tones of the new key.
4. Notes, starting at this point, should be named based on the new key. If the new key contains an E#, it should be written as such, and not as an F.