How to Transpose for a B-flat Instrument
Suppose you want to play a duet with your friend, who plays the clarinet (or the trumpet, or the saxophone). If the duet is scored for two flutes, trying to play it as it is would simply not work.
The reason behind this is that the clarinet is a transposing instrument, while the flute is not. What does this mean?
- When a flute player plays a written C, his/her flute sounds a C.
- When a clarinet player plays a written C, his/her clarinet sounds a B-flat.
That's why we say that the clarinet is a transposing instrument in B-flat. To be more accurate, not all clarinets are in B-flat: clarinets in other keys (in C, in A, in E-flat, just to name a few) also exist, but the B-flat clarinet is by far the most common variety.
As you may already have guessed, on such an instrument the whole scale gets transposed: a C sounds as a B-Flat, a D sounds as a C, an E sounds as a D and so on.
When is this a Problem?
Every time you wish to play a score written for C instruments (like the flute or the piano) but you need to substitute one or more of the instruments with transposing instruments (like clarinets, trumpets, saxophones). Here are some typical examples:
- You want to play a duet scored for two flutes, but you have a flute and a clarinet.
- You have a flute-and-piano score, but you want to play the flute part with a clarinet.
The problem only occurs when you mix different instruments: if you want to play a flute duet with two clarinets, the score can be played as is.
So, How Do I Solve the Problem?
You need to transpose all the parts that will be played by transposing instruments. For instance, let's say you want to change a flute duet into a flute-and-clarinet duet: in this case you only need to change one of the two staves, the one that will be played by the clarinet. Do not change the part that will be played by the flute!
What you need to do is basically to transpose all the notes on the staff up by a whole tone, or to be more precise by a major second. Here are the steps to accomplish this:
- Move all the notes up.
- Adjust the key signature.
- Fix any extra accidental.
Let's now explain these steps in detail.
- Move all the notes up. Get some blank staff paper. Transcribe all the notes of the part you want to adapt, but moving all of them up by one degree. Omit all the accidentals (sharps, flats and naturals) for the moment, we will put them in later.
For example, for
you would write
No changes whatsoever are to be made to the rhythms: the durations of the notes must be kept unchanged.
- Adjust the key signature. Let's say you know the order of sharps (F#, C#, G#, D#, A#, E#, B#) and flats (Bb, Eb, Ab, Db, Gb, Cb, Fb) in key signatures.
- If the original key signature has no flats, add the next two sharps.
- If the original key signature has just one flat, change it to an F# key signature.
- If the original key signature has at least two flats, remove the last two flats.
Before After 
Before After 
- Fix any extra accidental. You are almost done! Now you only need to search the original music for extra accidentals, and to translate them according to the following table:
Before After C# D# D# E# E# Fx F# G# G# A# A# B# B# Cx Before After C♮ D♮ D♮ E♮ E♮ F# F♮ G♮ G♮ A♮ A♮ B♮ B♮ C# Before After Cb Db Db Eb Eb F♮ Fb Gb Gb Ab Ab Bb Bb C♮
That's it! Now the part can be played on a B-flat clarinet (or trumpet, or saxophone), and it will sound fine even when played together with a C instrument like the flute. Remember, the flute must play the original version, not the modified one!