A French horn is a musical instrument made of brass tubing wound into a compact coil that is usually 12 to 13 feet (3.7 to 4.0 meters) long. There are several types, which differ primarily in terms of total tubing length and the number of fingered valves that can change the air flow through it. The French horn’s extreme length translates to a wide tonal range, with most models capable of nearly four full octaves of the musical scale. However, there are some limitations and considerations in terms of this range’s practical playability.
The earliest, most primitive design, known as a hunting or natural horn, is still used as a novelty instrument today. Its technical range is one single note, similar to that of a simple bugle. With techniques like varying the pursed aperture of the lips and muting its flared bell opening with the free hand, the musician can create only a few additional harmonic tones. There are no valves on it. It has a fixed tube length.
Valved horns are used in modern French horns. Simple piston valves, similar to those found on a trumpet, are used on some instruments, such as the so-called mellophone used by marching bands. The complex double piston system of the Vienna horn is operated by depressing long pushrods. Most orchestral French horns have rotary valves attached to short levers that work similarly to stopcock plumbing faucets. Valves change the path of air through the instrument, effectively changing its length in increments, allowing for fully chromatic pitch gradations within the range of a French horn.
The tubular length of a French horn is fixed, regardless of its valves. It’s built in the key of F, or the less common B-flat model. The basic range of a French horn with three control valves is from the bass F note three octaves below Middle C to the alto F note one octave above. Some horns are designed to accept crooks, which are extra lengths of brass tubing that can be used to change the factory-tuned key. The device effectively extends a French horn’s range.
The double horn is the most commonly used professional French horn design. It has a fourth valve that directs air flow through one set of tuned tubes tuned to F or another set tuned to B-flat. Triple horns, each with its own valve, extend the instrument’s tonal range to the second highest register among brass instruments.
The valves alone cannot produce all of the French horn’s potential notes. The harmonic overtones of the instrument’s defined key are mostly produced by the limited combinations of three valves. The horn player, also known as a hornist, must still create the other notes in between them using breath control and precise lip tension. This basic technique is known as embouchure. Skilled players can go beyond a French horn’s normal range and create midtones that are slightly off-key from standard musical notes.