Anatomy And Operation Of Brass Instruments

Anatomy And Operation Of Brass Instruments

Ever wonder how brass instruments work? In this article, I present the anatomy and operation of brass instruments:

Instrument Body

It is the central part of the instrument, it is a tube of different types of metal, mainly brass, straight or curved. Along the tube, there are parts welded by rings or links to join the total length of the instrument.


The Pipe has the same diameter or is slightly conical from the neck, together with the machinery and the framework of the different pumps, although it depends on the type of instrument and manufacturing design.


It is at the beginning of the body, it has a kind of socket welded, where the mouthpiece is placed, it has a larger internal diameter than the external diameter of the mouthpiece neck. For some instruments, such as the Flugelhorn or Flugelhorn in English, the neck, is the part to be adjusted for the main tuning, instead of the General Bomb (not for the rest of the bombs). Some manufacturers use copper in the necks, since it accelerates the general heating of the instrument, through the breath of the interpreter.


They are in the center of the instrument body approximately. They are mobile and removable parts, cylindrical and curved, they are used for a fine adjustment of the notes, and for cleaning and greasing them. Each one of them is a transposer of sound.

On the trumpet; the first piston moves the air to the first pump, and lowers a tone, from the G note of the second line of the staff, in Treble Clef to the F note of the first space. The second piston moves the air to the second pump and lowers half a step, from G to G flat. The third piston lowers a tone and a half, from G to E. Plus the different possible combinations, for example: lowering the first and the third that is; a tone, plus a tone and a half, transport the sound two and a half tones, this would be from Sol to D.


They are activated with a quick and straight movement, there is a direct passage of the air, from the main channel (which comes from the neck) towards the pump to which it belongs. Through some holes made in the piece, the air is moved to the corresponding pump and when it comes out of it, it continues through the main channel, until a different piston is activated or the activated one is released. The air always passes through the main pipe, regardless of whether they are activated or not. This principle will apply to other mechanisms.


In this mechanism, the air is moved to its corresponding pump. The movement of the cylinder, inside its compartment, is a turn of 1/4 of a turn, like when we tighten or loosen a cap. It is activated by a system of rods held by screws. , together with some keys called spatulas (they have that shape), to these, some springs are incorporated to automate the recoil of the entire system.

In some bugles, the cylinder is moved with the fingers holding it directly by its axis or with a kind of butterfly to facilitate its movement since they lack springs.

In the tenor trombone, pressing the lever that activates the cylinder, lowers a perfect fourth interval, from F of the fourth line to C of the second space, in Bass Clef, and their respective harmonics.

Both cylinders and pistons, in their construction, are perforated or mold the holes through which the air passes.

The cylinder is short and wide, while the piston is narrow and elongated. Both are introduced in a compartment called shirt

Like the pumps, they are removable for maintenance.

Rod System

On the trombone, it is used to change notes (there are valve trombones).

Being closed, we have the first position, in pistons, cylinders, or keys it is with all without pressing or in the air.

On air, the reference fundamental note is obtained; B flat low, and the entire harmonic series on top of this sound, although lower sounds can be achieved. their respective harmonics, just like in the first position.

This system can easily achieve a glissando (from the French; sliding), but in instruments with other mechanisms, this effect on the sound is quite complex, it depends more on the musician’s technique. It is achieved by giving a note and sliding the slide without stopping. to blow, obtaining a great number of harmonics and intermediate sounds.

At the end of the guide, the diameter is widened one or two millimeters, approximately twelve centimeters of travel to the end, using a soft step, for the precise adjustment of the two pieces, and, that there are no air losses.

In the curve of the rod, there is the drain key and a protective stop, welded in the middle of the curve, to which a rubber cover is placed to cushion possible blows.

Keys and Ears

System used in woodwind instruments, but in some metals such as the Serpentine (a kind of snake-shaped tuba), they have incorporated this tonal change system.

Natural Instruments

The instruments that do not have these mechanisms, called Natural, are limited to producing only the harmonics or natural notes, changing the pressure of the air and the lips.


To change the general tone, in some of these instruments, interchangeable pumps are used. The more travel these complementary pumps have, the lower the general tuning of the entire instrument. The first horns used this system, later they put the current valve mechanism.


Another way to modify the sound is by placing the hand inside the bell, as a mute, being able to correct the pitch somewhat, although this affects the timbre and color more than the height of the sounds. producing different sound effects.

On the horn and others, you can lower the overall tuning by up to one tone.

In summary; modifying sounds, timbre, pitch, etc. in these instruments, is achieved through:

Drain Faucet

The body of the instrument has one or several keys to expel the saliva and/or condensed vapor from its interior, it is usually in the general pump, or in the lower part of the instrument to facilitate the task. They are activated using a key in the shape of a lever.

At the end of the lever, a piece of cork, silicone, or rubber is glued, to prevent air leaks, if it is in poor condition, sound and timbre will be lost. Under the cork, there is another protruding tube welded to the pump, for where the water comes out

Bell or Pavilion

It is made of the same materials as the body and mouthpiece. It is located at the end of the entire pipe, widening it like a funnel. Help to amplify the sound. It can be welded on the body itself, assembled, or screwed, as is the case of the Horn and the Sousaphone, to facilitate its transport. The shape of the bell together with that of the mouthpiece facilitates the amplitude of the harmonics that the instrument can produce.

Building Materials

Mainly brass is used, depending on the proportion of the components, the metal will have greater or lesser quality, and will be more or less moldable, which will help its manufacture. They also make instruments from other materials; like plastic, to be used in brass bands or new students who start at an early age and don’t have the strength to use a heavier one.

The main advantage to getting one of these would be the weight, but as soon as we can, we should acquire one in good condition. As with the mouthpieces, a layer of lacquer is added to give shine to the sound and aesthetics.

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