Why a french horn have spit valve?

The primary reason for the spit valve on a french horn is to collect and remove excess moisture and saliva that accumulates inside the instrument during playing. Brass instruments, including the french horn, produce sound by vibrating the player's lips against the mouthpiece. This process naturally generates moisture, which can affect the sound quality and playability of the instrument. The spit valve allows players to conveniently expel this excess moisture, preventing it from hindering their performance.

Moisture can cause several problems for french horn players. It can make the instrument's notes sound muffled or unclear. It can also make the instrument more difficult to play, as the moisture can make the valves sticky or sluggish. In extreme cases, moisture can even cause the instrument to crack or damage.

The spit valve is typically located at the bottom of the french horn, near the bell. It is a small, spring-loaded valve that can be opened and closed by pressing a lever with the player's thumb. When the lever is pressed, the valve opens and allows the moisture to drain out.

Players typically empty their spit valves during pauses in their playing. It is important to empty the spit valve regularly to prevent moisture from building up and causing problems. Some players also use a cloth to wipe away any remaining moisture from the inside of the instrument.

By regularly emptying the spit valve, french horn players can maintain the sound quality and playability of their instruments and prevent damage caused by moisture buildup.