Music theory The basics
Concert pitch and transposing instruments
Why a clarinet, saxophone or horn sounds a different note from the one written, with worked examples and octave transposers.
Practise this on its own page: Transposer.
Written pitch and concert pitch
Concert pitch is the note you actually hear. Written pitch is the note printed in the player's part.
For most instruments, such as piano, flute, violin and oboe, these are the same. A transposing instrument is one where the written note and the sounding note are different.
Why some instruments transpose
Many instruments come in families of different sizes, such as clarinets and saxophones. Writing their music this way means a player can switch between sizes and keep the same fingering for each written note, without relearning the instrument.
The naming rule
The key in an instrument's name tells you what you hear when the player reads a written C. A clarinet in B-flat plays a written C and you hear B-flat. A horn in F plays a written C and you hear F.
| Instrument | Written C sounds as | Sounds this much lower than written |
|---|---|---|
| Clarinet in Bb | Bb | Major 2nd |
| Trumpet in Bb | Bb | Major 2nd |
| Clarinet in A | A | Minor 3rd |
| Horn in F | F | Perfect 5th |
| Cor anglais (in F) | F | Perfect 5th |
| Alto saxophone in Eb | Eb | Major 6th |
| Tenor saxophone in Bb | Bb | Major 9th (an octave plus a major 2nd) |
| Baritone saxophone in Eb | Eb | An octave plus a major 6th |
Worked examples
Because the instrument sounds lower than written, its music is written higher by the same interval. A B-flat clarinet sounds a major 2nd lower, so a piece in concert C major is written for it in D major.
An alto saxophone sounds a major 6th lower. To hear a concert C, the part shows an A, which is a major 6th above C.
A horn in F sounds a perfect 5th lower. To hear a concert C, the horn part shows a G, which is a perfect 5th above C.
Octave transposers
Some instruments sound in the same key as written but in a different octave. This keeps their notes on the stave instead of on lots of ledger lines. Some books do not call these transposing instruments at all, because the letter names stay the same.
- Guitar: sounds an octave lower than written.
- Bass guitar: sounds an octave lower than written.
- Double bass: sounds an octave lower than written.
- Piccolo: sounds an octave higher than written.
- Xylophone: sounds an octave higher than written.
- Glockenspiel: sounds two octaves higher than written.