Most horns have lever-operated rotary valves, but some, especially older horns, use piston valves (similar to a trumpet's) and the Vienna horn uses double-piston valves, or pumpenvalves. 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. A musician who plays a horn is known as a horn player or hornist.
The double horn in F/B ♭ (technically a variety of German horn) is the horn most often used by players in professional orchestras and bands, although the descant and triple horn have become increasingly popular. The French horn (since the 1930s known simply as the horn in professional music circles) is a brass instrument made of tubing wrapped into a coil with a flared bell.
