Pitch is controlled through the combination of the following factors: speed of air through the instrument (controlled by the player's lungs and thoracic diaphragm); diameter and tension of lip aperture (by the player's lip muscles—the embouchure) in the mouthpiece; plus, in a modern horn, the operation of valves by the left hand, which route the air into extra sections of tubing.

The backward-facing orientation of the bell relates to the perceived desirability to create a subdued sound in concert situations, in contrast to the more piercing quality of the trumpet.

[4] When playing higher notes, the majority of players exert a small degree of additional pressure on the lips using the mouthpiece.

At that time, French makers were preeminent in the manufacture of hunting horns and were credited with creating the now-familiar, circular "hoop" shape of the instrument.

It retains the narrow bell-throat and mouthpipe crooks of the orchestral hand horn of the late 18th century, and most often has an "ascending" third valve.

By combining a long length with a narrow bore, the French horn's design allows the player to easily reach the higher overtones which differ by whole tones or less, thus making it capable of playing melodies before valves were invented.

[10] In the mid-18th century, horn players began to insert the right hand into the bell to change the length of the instrument, adjusting the tuning up to the distance between two adjacent harmonics depending on how much of the opening was covered.

Valves' unreliability, musical taste, and players' distrust, among other reasons, slowed their adoption into the mainstream.

[citation needed] There were many different versions of early valves, most being variants of the piston and rotary systems used in modern horns.

Dennis Brain's benchmark recordings of the Mozart Horn Concerti were made on a single B♭ instrument by Gebr.

[14] In the US, the two most common styles ("wraps") of double horns are named Kruspe and Geyer/Knopf, after the first instrument makers who developed and standardized them.

In the United States, the Conn 8D, a mass-produced instrument based on the Kruspe design, has been extremely popular in many areas (New York, Los Angeles, Cleveland, Philadelphia).

The CF Schmidt double, with its unique piston change valve, is occasionally found in sections playing Geyer/Knopf model equipment.

[16] The horn, although not large, is awkward in its shape and does not lend itself well to transport where space is shared or limited, especially on planes.

Although a few recent composers have written specifically for the natural horn (e.g., György Ligeti's Hamburg Concerto), today it is played primarily as a period instrument.

Manufacturing of this instrument sharply decreased in the middle of the 20th century, and this mellophone (or mellophonium) rarely appears today.

A derivative of the F alto horn, it is keyed in F. It is shaped like a flugelhorn, with piston valves played with the right hand and a forward-pointing bell.

Mellophones are, however, sometimes unpopular with horn players because the mouthpiece change can be difficult and requires a different embouchure.

[18] As an instrument it compromises between the ability to sound like a horn, while being used like a trumpet or flugelhorn, a tradeoff that sacrifices acoustic properties for ergonomics.

Despite its name and its somewhat tuba-shaped appearance, it is generally not considered part of the tuba family, because the instrument's relatively narrow bore causes it to play more like a horn.

It is usually played in a range similar to that of the euphonium, but its possible range is the same as that of the horn, extending from low F♯, below the bass clef staff to high C above the treble staff when read in F. The low pedal tones are substantially easier to play on the Wagner tuba than on the horn.

The horn is most often used as an orchestral and concert band instrument, with its singular tone being employed by composers to achieve specific effects.

Once the technique of hand-stopping had been developed, allowing fully chromatic playing, composers began to write seriously for the horn.

These include Poulenc (Elegie) and Saint-Saëns (Morceau de Concert for horn and orchestra, op.

Others, particularly Wolfgang Amadeus Mozart, whose friend Joseph Leutgeb was a noted horn player, wrote extensively for the instrument, including concerti and other solo works.

Mozart's A Musical Joke satirizes the limitations of contemporary horn playing, including the risk of selecting the wrong crook by mistake.

These include composer/arranger Gil Evans who included the French horn as an ensemble instrument from the 1940s, first in Claude Thornhill's groups, and later with the pioneering cool jazz nonet (nine-piece group) led by trumpeter Miles Davis, and in many other projects that sometimes also featured Davis, as well as Don Ellis, a trumpet player from Stan Kenton's jazz band.

Notable works of Ellis' jazz French horn include "Strawberry Soup" and other songs on the album Tears of Joy.

Notable improvising horn players in jazz include Julius Watkins, Willie Ruff, John Graas, David Amram, John Clark, Vincent Chancey, Giovanni Hoffer, Arkady Shilkloper, Adam Unsworth, and Tom Varner.

People who are more notable for their other achievements, but also play the horn, include actors Ewan McGregor and David Ogden Stiers, comedian and television host Jon Stewart, journalist Chuck Todd, The Who bassist and singer John Entwistle, and rapper and record producer B.o.B.