I'm really new to music theory and I'm trying to figure this out. I need to transpose a score in B major to the key Bb major. When I click transpose, should it be up, or down, and what interval should it be?

2 Answers 2


From B major to Bb major is one semitone down. On most computer music programs this would be achieved by changing it -1.

Technically you can get from one key to another in either direction, up or down since the 12 notes cycle around but in this case -1 is the obvious choice since the other option is +11.

  • Can't fault this! Although the question is naiive.
    – Tim
    Dec 3, 2020 at 20:40

I've seen transposing function in a few different notation programs. They will differ from program to program, options I have seen include:

  • direction up/down
  • interval of transposition
  • diatonic or chromatic

Watch out for enharmonic spelling changes

Sometimes software offers a 'key change' type function.

You need to transpose down one half step. If you have a diatonic/chromatic option, you want to do it chromatically.

  • In some software (like Sibelius), transposing down a half step from B will give you A#, so you will want to select the "diminished unison" interval to make this transposition to Bb, instead.
    – Peter
    Dec 3, 2020 at 22:23
  • @Peter it seems to me that it ought to be an augmented unison. For it to make sense as a diminished unison, you have to say that you're going up by a diminished unison to get from B to B flat, which is just weird. Going down by an augmented unison is much more sensible.
    – phoog
    Dec 4, 2020 at 5:03
  • @phoog I think you're right. Unfortunately, I don't have access to the software to check right now, but I do know you want to use some kind of unison to make this transposition.
    – Peter
    Dec 4, 2020 at 13:23
  • A diminished unions would be -1 half steps, So if up means add and down means subtract, 0 + (-1) = -1 down a half step, and 0 - (-1) = 1 up a half step. I think is is what @phoog means. Right? Bizarre! Dec 4, 2020 at 14:19

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