Single French horns
A single French horn consists of a standard conical bore with three or four rotary valves. It is commonly used in orchestral performances. Single French horns can be hard to play in the higher ranges.
Double French horns
A double French horn consists of two horns in one frame: a B-flat and an F horn. It has a thumb-operated fourth valve that allows the player to switch from a brighter, B-flat tone to warmer, deeper F tone.
Vienna French horns
A Vienna French horn uses a Pumpenvalve instead of the traditional piston or rotary valves. It changes keys using a crook system just like a Natural French horn. Vienna French horns produce opulent legato sounds due to their extended bell flare.
Marching French horn
A marching French horn commonly has a B flat alto pitch. Those with F alto pitch are called mellophones. Marching French horns provide improved projection, lighter weight, and easier playing position. They are popularly played in formation marches.
Triple French horn
A triple French horn has an added E flat alto or F key. It is more expensive than the other types of horns. The bell can be detached when fitting it inside a case. However, triple French horns are still heavy instruments with awkward shapes that make them quite cumbersome to bring along.