When we talked about scales, we moved a C major scale up and wrote the same music beginning on D. This process, called transposition, created a D major scale.
Transposition is a regular part of almost all music making, and we need to know how to get all of our instruments to play music together. The transposing instruments come in various keys, but there are a couple of simple rules to help us adjust our notation. We will use the word “sound” to talk about the actual note a transposing instrument plays.
Reading Transposed Music
The rule for reading from transposed music to figure out the correct sounding pitches goes like this:
If you see a C, the transposing instrument sounds its key.
So, let’s try a real example. Here is an excerpt of a Clarinet in B flat part.
[Symphony No. 8 in F major, Op. 93 by Ludwig van Beethoven, 1st movement, mm. 1-8, Clarinet 1]
So if it is a Clarinet in B flat, a written C will sound as B flat.
This means that for every note the clarinetist plays, we actually get the note a whole step lower. Let’s start from the beginning:
- written G sounds F
- written D sounds C
- two written Gs sound two Fs
- written F sharp sounds E
- another written D sounds C
- written E sounds D
- another written F sharp sounds E
- another written G sounds F
- and written A sounds G
Here is the whole line tranposed to sounding pitch to check our work. Note that in measure 5 above, the written Cs become B flats in the example below.
We can apply this logic to the key as well. This music has a key signature for G major (or E minor). A whole step below G is F, so the music is in F major. (And if you see the note below the excerpt, you will see the symphony is in F major.)
There are a few basic transpositions you should know:
- B flat (clarinet, trumpet): down a M2 (whole step)
- E flat (alto saxophone): down a M6
- F (horn): down a P5
You should also know that there are instruments in C, but transpose by octave:
- octave lower than written: double bass, guitar, tenor voice in treble clef
- octave higher than written: piccolo
And there are also instruments that combine the two:
- B flat plus octave lower (down a M9): bass clarinet, tenor saxophone
- E flat plus octave lower (down a M13): baritone saxophone
Creating Transposed Parts
The rule for taking nontransposed music and creating a part for a transposing instrument is this:
If you see the instrument’s key note, the transposing instrument plays a C.
Let put this one into action. Here’s a melody we want a B flat Clarinet to play.
[Symphony no. 40 in G minor, K. 550 by Wolfgang Amadeus Mozart, 1st movement, mm. 1-16, Oboe 1, 1st version]
This is something Mozart actually did. He wrote his famous G minor symphony without clarinets and later added two, taking music from the oboes. Notice the key signature matches G minor.
So if we see a B flat in the oboe part, we should make it a C for the clarinet. So every note needs to go up a whole step.
Ignoring the violin cue and starting from the p:
- written F sharp sounds G sharp
- written G sounds A
- written A sounds B
- written B flat sounds C
- and written C sounds D
- the rest of the line goes back down on the same notes
So let’s see the Clarinet part Mozart made to check our work.
[Symphony no. 40 in G minor, K. 550 by Wolfgang Amadeus Mozart, 1st movement, mm. 1-16, Clarinet 1, 2nd version]
It matches, and the key signature is a whole step higher as well: G minor becomes A minor.
Make sure you can take transposed music and read it in concert pitch, and also create tranposing parts out of nontransposed music.