Trumpet - Construction

Construction

The trumpet is constructed of brass tubing bent twice into a rounded oblong shape. The trumpet and trombone share a roughly cylindrical bore, which results in a bright, loud sound. The bore is actually a complex series of tapers, smaller at the mouthpiece receiver and larger just before the flare of the bell begins; careful design of these tapers is critical to the intonation of the instrument. By comparison, the cornet and flugelhorn have conical bores and produce a more mellow tone. Bore sizes generally range from 0.430 to 0.472 inches and are usually listed as medium, medium large and large from various manufacturers.

As with all brass instruments, sound is produced by blowing air through closed lips, producing a "buzzing" sound into the mouthpiece and starting a standing wave vibration in the air column inside the trumpet. The player can select the pitch from a range of overtones or harmonics by changing the lip aperture and tension (known as the embouchure). The mouthpiece has a circular rim, which provides a comfortable environment for the lips' vibration. Directly behind the rim is the cup, which channels the air into a much smaller opening (the back bore or shank) that tapers out slightly to match the diameter of the trumpet's lead pipe. The dimensions of these parts of the mouthpiece affect the timbre or quality of sound, the ease of playability, and player comfort. Generally, the wider and deeper the cup, the darker the sound and timbre.

Modern trumpets have three (or infrequently four) piston valves, each of which increases the length of tubing when engaged, thereby lowering the pitch. The first valve lowers the instrument's pitch by a whole step (2 semitones), the second valve by a half step (1 semitone), and the third valve by one-and-a-half steps (3 semitones). When a fourth valve is present, as with some piccolo trumpets, it lowers the pitch a perfect fourth (5 semitones). Used singly and in combination these valves make the instrument fully chromatic, i.e., able to play all twelve pitches of classical music. For more information about the different types of valves, see Brass instrument valves.

The pitch of the trumpet can be raised or lowered by the use of the tuning slide. Pulling the slide out lowers the pitch; pushing the slide in raises it. To overcome the problems of intonation and reduce the use of the slide, Renold Schilke designed the tuning-bell trumpet. Removing the usual brace between the bell and a valve body allows the use of a sliding bell; the player may then tune the horn with the bell while leaving the slide pushed in, or nearly so, thereby improving intonation and overall response.

A trumpet becomes a closed tube when the player presses it to the lips; therefore, the instrument only naturally produces every other overtone of the harmonic series. The shape of the bell makes the missing overtones audible. Most notes in the series are slightly out of tune and modern trumpets have slide mechanisms built in to compensate.