The Structure of the Horn
Slightly different from other brass instruments

Compared with the simple animal-horn instruments of the past, the modern horn is highly complex instrument with coiled tubing. Let's take a look at the structure and how that structure affects the timbre.
Though the soft timbre characteristic of the horn allows it to blend well with strings and woodwinds, it is also capable of bold, dynamic tones when playing with other horns and brass instruments. This wide tonal range makes it an appealing instrument for composers, which is why the horn is one of those instruments that seems to be everywhere, even in orchestral music. Let's listen to some exemplary pieces.
The first is an example of the horn's dulcet tones from Brahm's Symphony No. 1 in C minor, Op. 68, and the other is a powerful performance from Wagner's Tannhäuser.



Can you hear the difference? In both cases, the horn impressively expands to fill the space.

The bell of the natural horn was said to face backwards so that the horn could be carried on the shoulder. The bell of today's horn also faces towards the rear of the player. How does this backward-facing bell affect the tone?
Indoors, the horn's tone reflects off of the wall at the back of the stage before arriving at the audience. Thus, the quality of the tone will be affected by the materials used to make that wall.

Generally, the reason why people say that the tone of the horn is soft is because it loses its edge when it reflects off of the wall, but when the listener faces the bell directly, it has that boisterous tone characteristic of brass instruments. Let's take a listen. When heard from behind the player, the tone has quite an impact.

The tone is soft when heard from in front of the player.

The tone is more boisterous when the listener is facing the bell.

With most brass instruments, the levers or pistons are operated with the right hand. With the horn, however, the player puts the right hand into the bell, and so the levers are operated with the index, middle, and ring fingers of the left hand. The instrument is supported with the little finger of the left hand and the thumb of the right hand inside the bell. Some weight is also placed on the skin between the thumb and index finger on the left hand. Because of the weight of the instrument, people who practice a lot sometimes get what are called horn calluses.
The weight of the instrument will depend on the thickness of the metal that forms the tube, but generally speaking, a single will weigh 2kg; a semi-double, 2.3kg; a full-double, 2.5kg; and a triple, 2.8kg. An increase of only 0.1kg will put a crushing weight on the little finger of the left hand.