3.1 Transposition: changing keys

Changing the key of a piece of music is called transposing the music. Music in a major key can be transposed to any other major key; music in a minor key can be transposed to any other minor key. (Changing a piece from minor to major or vice-versa requires many more changes than simple transposition.) A piece will also sound higher or lower once it is transposed. There are some ways to avoid having to do the transposition yourself, but learning to transpose can be very useful for performers, composers, and arrangers.

Why transpose?

Here are the most common situations that may require you to change the key of a piece of music:

• To put it in the right key for your vocalists . If your singer or singers are struggling with notes that are too high or low, changing the key to put the music in their range will result in a much better performance.
• Instrumentalists may also find that a piece is easier to play if it is in a different key. Players of both bowed and plucked strings generally find fingerings and tuning to be easier in sharp keys, while woodwind and brass players often find flat keys more comfortable and in tune.
• Instrumentalists with transposing instruments will usually need any part they play to be properly transposed before they can play it. Clarinet , French horn , saxophone , trumpet, and cornet are the most common transposing instruments .

Avoiding transposition

In some situations, you can avoid transposition, or at least avoid doing the work yourself. Some stringed instruments - guitar for example - can use a capo to play in higher keys. A good electronic keyboard will transpose for you. If your music is already stored as a computer file, there are programs that will transpose it for you and display and print it in the new key. However, if you only have the music on paper, it may be easier to transpose it yourself than to enter it into a music program to have it transposed. So if none of these situations apply to you, it's time to learn to transpose.

How to transpose music

There are four steps to transposition:

1. Choose your transposition.
2. Use the correct key signature .
3. Move all the notes the correct interval .
4. Take care with your accidentals .

Step 1: choose your transposition

In many ways, this is the most important step, and the least straightforward. The transposition you choose will depend on why you are transposing. If you already know what transposition you need, you can go to step two. If not, please look at the relevant sections below first:

• Are you rewriting the music for a transposing instrument ?
• Are you looking for a key that is in the range of your vocalist ?
• Are you looking for a key that is more playable on your instrument?