I will also discuss mutes, ensemble placement, and the more peculiar aspects of the instrument. In assessing the needs of young French horn players, one must first come to understand the peculiarities of the instrument itself and how it differs from other brass instruments. The French horn is an instrument built for its sound, not for overall efficiency. This disparity creates more resistance, or back pressure, that must be overcome by the student. The large bell size also adds resistance and weight to the instrument.
Rotary valves are another unique aspect of the instrument.
Rotary valves are generally more sluggish than piston valves, using indirect action as opposed to the direct action of piston valves. They also create 90-degree turns in the air stream, which again, increases resistance. For this reason, it often takes students longer to learn fingerings on the horn than it does on other brass instruments. How To String A Rotary Valve '.