Instrument reference · brass

French horn

By Band Tuning editorial · Facts checked 15 September 2026

The horn is a transposing instrument written in F but sounding a perfect fifth below. ^2,3 The fundamental of the F side is F1 and of the B♭ side B♭1; the F tube is about 12 feet long.²

The frequencies on this page are computed from the pitch standard A4 = 440 Hz, the 1939 London conference standard reaffirmed by ISO in 1975, in twelve-tone equal temperament, which divides the octave into twelve equal semitones: f = 440 × 2^(n/12), where n is the number of semitones above A4 (negative below). ¹ The notes are named in scientific pitch notation, where C4 is middle C.

Tuning notes and reference pitches

In a band's daily tuning the concert B♭ is the note this instrument tunes to, and the source says to warm up before tuning and to use no vibrato. ⁶ The table gives every octave of that note inside the instrument's sounding range, the note the player reads for it, and its frequency. The browser tuner plays each of these as a reference tone.

How the pitch is adjusted

• Slides pulled out play flatter, pushed in sharper. ⁶
• Each valve loop has its own tuning slide, and each side of a double horn, F and B♭, has a general tuning slide. ²
• Putting the right hand in the bell alters the tone and fine-tunes the pitch, which the maker's guide calls one of the horn's distinctive traits. ⁴

Every note in the range at A4 = 440 Hz

B1 to F5, double horn in F and B♭, sounding. ⁵ The written column is the note the player reads; the sounding column is what a tuner hears.

Maker's specification

Figures as printed in the maker's catalogue for its standard and intermediate models; a bore is the inside diameter of the tubing, a bell the diameter of its rim.

The family: other keys and sizes

Notes from the sources

• The modern double horn evolved from natural horns; piston valves were added in the early nineteenth century, rotary valves around 1830, and the fourth rotor with a second set of slides in 1898. ²
• The three rotary valves are worked by the first three fingers of the left hand; the thumb valve switches between the F and B♭ sides. ²
• The semi-double horn is a B♭ horn with a supplementary F tube, lighter than the full double. ⁴