Definition
To transpose means to move a piece or a part by a fixed interval, keeping the relationships unchanged. A transposing instrument is an instrument whose part is written at a pitch different from the real one: the musician reads “C” but plays another note. The note you hear is called the sounding pitch (concert pitch, “in C”).
Why they exist
Because of the construction history of the instruments: a clarinetist who switches from the Bb clarinet to the A clarinet reads the same fingering for the same written note; a saxophonist reads the same way on alto, tenor and baritone. The instrument takes its name from the note you hear when you read C.
Table of the main instruments
| Instrument | Key | Written C sounds | To write the part |
|---|---|---|---|
| Bb clarinet, Bb trumpet, soprano sax | Bb | Bb, a major 2nd below | write a major 2nd above |
| Tenor sax, bass clarinet (French notation) | Bb | Bb, a major 9th below | write a major 9th above |
| A clarinet | A | A, a minor 3rd below | write a minor 3rd above |
| Alto sax | Eb | Eb, a major 6th below | write a major 6th above |
| Baritone sax | Eb | Eb, an octave + major 6th below | write a major 13th above |
| Eb clarinet (small) | Eb | Eb, a minor 3rd above | write a minor 3rd below |
| Horn in F, English horn | F | F, a perfect 5th below | write a perfect 5th above |
| Alto flute in G | G | G, a perfect 4th below | write a perfect 4th above |
| Piccolo, celesta, xylophone | C | an octave above | write an octave below |
| Glockenspiel | C | two octaves above | write two octaves below |
| Guitar, bass, double bass, contrabassoon | C | an octave below | write an octave above |
Key signatures of transposing instruments
The key signature is transposed too: for instruments in Bb, 2 sharps are added (or 2 flats removed): a piece in Eb major (3b) → trumpet part in F major (1b). For instruments in Eb, 3 sharps are added: a piece in Eb (3b) → alto sax in C major. For the horn in F, 1 sharp is added. Many horn parts, by tradition, are written with no key signature, using accidentals.
Transposing a piece (for voices and bands)
- By interval: move every note by the same interval, then change the key signature. C major → E major (+4 semitones): C→E, F→A, G→B, Am→C#m.
- By degrees: think in Roman numerals (I–V–vi–IV) and reapply them to the new key: it is the quickest and safest method.
- By clef (seven-clef system): reading in another clef transposes automatically (a conservatory technique).
- Capo: on the guitar, a capo on the 2nd fret turns C shapes into an actual D.
Transposition in the DAW
In FL Studio you can transpose patterns by selecting the notes in the Piano roll (Ctrl + up/down arrows = octave, Shift + arrows = semitone) or with the channel's Pitch parameter. Be careful: transposing audio by more than 3–4 semitones alters the formants of the voice (“chipmunk” effect); use algorithms with formant preservation (Elastique Pro in FL, Melodyne). For orchestral virtual instruments, parts are always programmed at sounding pitch, but if you print parts for real musicians you have to transpose them.
Examples
- In big bands (Count Basie, Thad Jones) the sax section reads parts in Eb (altos, baritone) and in Bb (tenors): the lead alto of any chart is written a major 6th above the sounding pitch.
- In “Rhapsody in Blue” (Gershwin) the famous opening trill and glissando is for Bb clarinet: the written part starts from a low G that sounds F.
- Many pop singers record in one key and then the song is transposed by a semitone for live: with Roman numerals the change is immediate.
Exercise
- Write the melody of “Frère Jacques” in C major and transpose it for Bb trumpet, Eb alto sax and F horn.
- Transpose one of your I–V–vi–IV progressions from C to Eb, A and F# thinking only in degrees.
- In FL Studio, transpose a vocal by +3 semitones with and without formant preservation and compare.
Related topics
Intervals and their inversions; Key signatures; Reading the orchestral score; Orchestration: families, ranges and blends.