Concert pitch is the actual pitch that an instrument sounds, as opposed to the pitch that is written in its music. A Bb trumpet is a transposing instrument: when it plays a written C, it sounds as Bb, a whole tone lower, so its music must be written a whole tone higher than concert pitch.
What is concert pitch?
Concert pitch is the actual pitch that an instrument sounds, as opposed to the pitch that is written in its music. A piano is a concert pitch instrument: when it plays a written C, it sounds as C, so the written pitch and the sounding pitch are the same. A Bb trumpet is a transposing instrument: when it plays a written C, it sounds as Bb, a whole tone lower, so its music must be written a whole tone higher than concert pitch, or it will play in the wrong key. The standard for concert pitch is A4 at 440 Hz, which is the pitch that orchestras tune to. Concert pitch matters because different instruments are built in different keys, and they must all sound together in the same key. A Bb clarinet, an Eb alto saxophone, a French horn in F, and a piano all play the same piece, but their music is written in different keys, so that they all sound in the same key, which is the concert key. The trumpet's music is written a whole tone higher than concert pitch, the alto saxophone's music is written a major 6th higher than concert pitch, and the French horn's music is written a perfect 5th higher than concert pitch. The note frequency calculator shows the frequency of any note at concert pitch.
How concert pitch and transposing instruments work
A transposing instrument sounds at a different pitch from the pitch that is written, by a fixed interval, which is the interval of the instrument. A Bb trumpet sounds a major 2nd, a whole tone, below what is written, so a written C sounds as Bb, and a written D sounds as C. An Eb alto saxophone sounds a major 6th below what is written, so a written C sounds as Eb, and a written G sounds as Bb. A French horn in F sounds a perfect 5th below what is written, so a written C sounds as F, and a written G sounds as C. The guitar sounds an octave below what is written, so a written E4 sounds as E3, which is why guitar music is written an octave higher than it sounds. To write music for a transposing instrument, transpose the concert pitch up by the interval of the instrument. A piece in concert C major, written for a Bb trumpet, must be written in D major, a whole tone higher, so that the trumpet sounds in C major. A piece in concert Eb major, written for an Eb alto saxophone, must be written in C major, a major 6th higher, so that the saxophone sounds in Eb major. The key of C major is the concert key, and the key of D major is the key the trumpet's music is written in.
Worked example — a trumpet and a piano playing together. A piano plays a melody in concert C major, with the notes C, E, G, E, D, C. A Bb trumpet joins in, and its music must be written a whole tone higher, in D major, so that it sounds in C major. The trumpet's written notes are D, F#, A, F#, E, D, which are the notes of D major, and when the trumpet plays them, they sound as C, E, G, E, D, C, which is the same melody as the piano, in concert pitch. The trumpet's written key is D major, but its sounding key is C major, and the two instruments are in tune with each other. The chord transposer works out the written key for any concert key.
How to practise concert pitch
Practise by working out the written key for a transposing instrument, so the interval becomes automatic and you can play with any instrument without confusion.
- Work out the written key for a Bb trumpet playing in concert C major, by transposing up a whole tone, to D major, and check your answer.
- Work out the written key for an Eb alto saxophone playing in concert Eb major, by transposing up a major 6th, to C major, and check your answer.
- Play the I–V–vi–IV progression in C major on piano, and work out the chords a Bb trumpet would read, in D major.
- Practise with the note frequency calculator to find the frequency of any note at concert pitch, and compare it with the written pitch.
- Use the chord transposer to transpose a piece from concert pitch to the written key of a transposing instrument.
Common mistakes
- Confusing the written key with the sounding key — A Bb trumpet's written key is a whole tone higher than its sounding key, so a trumpet reading D major is sounding in C major. Confusing the two will make the trumpet play in the wrong key, a whole tone too high.
- Transposing in the wrong direction — To write for a transposing instrument, transpose the concert pitch up by the interval of the instrument, not down. A Bb trumpet needs its music written a whole tone higher, not lower, or it will sound a whole tone too low.
- Forgetting that the guitar is a transposing instrument — The guitar sounds an octave below what is written, so a note written as E4 on guitar sounds as E3 on piano. Forgetting the octave will make the guitar sound an octave too low when it plays with a piano.
Quick reference
This table lists the five common transposing instruments, with the interval each one sounds below what is written and the note a written C sounds as on each one, so you can see the transposition working in every row. The piano is included for comparison, because it is a concert pitch instrument, and its written C sounds as C.
| Instrument | Sounds | Written C sounds as |
|---|---|---|
| Piano | As written | C |
| Guitar | An octave below | C (an octave lower) |
| Bb trumpet | A major 2nd below | Bb |
| Bb clarinet | A major 2nd below | Bb |
| Eb alto saxophone | A major 6th below | Eb |
| French horn in F | A perfect 5th below | F |
Use the table as a reference when you play with a transposing instrument, and test yourself by covering the third column and working out the sounding note from the instrument and the interval. When you can work out the sounding pitch of any transposing instrument without looking, you can play with any musician, in any key, and always be in tune.
Frequently asked questions
What is concert pitch?
Concert pitch is the actual pitch that an instrument sounds, as opposed to the pitch that is written in its music. A Bb trumpet is a transposing instrument: when it plays a written C, it sounds as Bb, a whole tone lower, so its music must be written a whole tone higher than concert pitch.
What is A440?
A440 is the standard for concert pitch: the note A above middle C, A4, is tuned to 440 Hz, and all other notes are tuned relative to it. Orchestras tune to A440, and it is the standard that pianos, guitars and all concert pitch instruments use.
Which instruments are transposing instruments?
Bb trumpet and Bb clarinet, which sound a whole tone below what is written, Eb alto saxophone, which sounds a major 6th below, French horn in F, which sounds a perfect 5th below, and guitar, which sounds an octave below what is written.
Why are some instruments transposing instruments?
Because they were built in a particular key, and their music is written so that the fingerings are comfortable, even though the sounding pitch is different. A Bb trumpet's written C is the fingering for its open note, even though it sounds as Bb, and the notation is designed for the player, not for the listener.
How do I write music for a transposing instrument?
Transpose the concert pitch up by the interval of the instrument: a piece in concert C major, written for a Bb trumpet, must be written in D major, a whole tone higher, so that the trumpet sounds in C major.