Alto Flute
Quick Facts
- Instrument Key
- G
- Transposition Interval
- Perfect 4th down
- Written C sounds as
- G3
- Instrument Family
- woodwind
- Instrument Page
- Alto Flute on Tunable
Written vs. Sounding Pitch — Frequency Table
Each row shows a written pitch (as it appears in the score) and the concert-pitch note that sounds when played. Frequencies are equal temperament at A4=440Hz.
Key Signature Conversion Table
When the conductor names a concert key, this table shows what key signature the Alto Flute player reads. The player reads the written key; the audience hears the sounding key.
Practical Scenarios
Playing a Melody in Concert C: Alto Flute Reading
The melody is in concert C major. The alto flute player reads F major (one flat) — each written note sounds a perfect fourth lower. Written C sounds G, written F sounds C, written G sounds D.
Switching from Concert Flute to Alto Flute
A flute player picking up the alto flute for a chamber piece must adjust for the G transposition. Written C4 on concert flute sounds C4; on alto flute, written C4 sounds G3 — a fourth lower. All fingerings are the same; the interval shift requires careful score reading.
Holst "The Planets": Ensemble Blend with Other Flutes
In the "Saturn" movement, Holst scores alto flute for its haunting low register. The alto flute reads the part in G transposition; when the full flute section plays in unison, the director must verify the transposed pitches align correctly across concert flute, piccolo, and alto flute.
Why Does the Alto Flute Transpose?
The alto flute is the only standard orchestral transposing flute, pitched a perfect fourth below the concert flute. It is the largest and lowest member of the orchestral flute family (excluding the bass flute, which is rarely used). The G transposition means written C4 sounds as G3. The alto flute's rich, breathy low register and warm tone color have attracted composers seeking ethereal or other-worldly effects: Ravel's Daphnis et Chloe, Holst's The Planets, and Stravinsky's The Rite of Spring all feature alto flute writing. The instrument's G transposition is unique among woodwinds — neither Bb nor Eb nor F — making it a standalone key group.
Tune Your Alto Flute with Precision — Get Tunable.
Tunable's chromatic tuner shows exact Hz values in real time. Tune to equal temperament A4=440Hz or explore all 16 temperament systems.
Related Instruments
How to Transpose for G Instruments
All Transposing Instruments · Circle of Fifths · Keys Reference · Temperament Systems