History of French horn

The French or orchestral horn, often referred to as simply a horn, acts as a bridge between the woodwind and brasswind sections of an ensemble.  It has an early history similar to the trumpet's.  It originally didn't have valves, so players used their hand to alter the pitch.  Half-covering the bell lowered the pitch by a half step, and completely covering the bell raised it by a half step.  By the mid-18th century, this so-called "hand stopping" was the norm.  Even after the introduction of valves, a player still puts their right hand in the bell because it's part of the instrument's character.

Players still needed to change crooks to make the key of the horn closely match the key of their music.  One attempt to change this was the omnitonic horn.  It included all of the different crook lengths on the horn's body.  Instead of manually inserting and removing these crooks, players switched between them by turning a dial.  However, the instrument was heavy and cumbersome, so it never caught on.

Valves were introduced in the early 19th century by Stölzel and Blühmel.  These new valved horns had a consistent tone, were easier to play, and could play all chromatic notes.  They became standard by the late 19th century.

Today, the horn consists of a body, bell, valve system, mouthpiece, and mouthpiece.  The shape of its mouthpiece produces a mellower sound than other brass instruments.  The most popular horn is the F/Bb horn, which utilizes two sets of tubing to play in two different keys.  This allows the player to play some extra notes and keep others in tune.  The horn's compass extends from D to c'''.