Brass instrument
Brass instrument, in music, any wind instrument—usually of brass or other metal but formerly of wood or horn—in which the vibration of the player’s lips against a cup- or funnel-shaped mouthpiece causes the initial vibration of an air column. A more precise term is lip-vibrated instrument. Ethnologists frequently refer to any instrument of this class as a trumpet; but when they are made of or derived from animal horns, they are also often known as horns. Typical brass instruments in a Western orchestra are the trumpet, trombone, French horn, and tuba.
- Brass instruments are defined not by their construction material but by the vibration of the player’s lips against a mouthpiece.
- The length of a brass instrument’s tubing determines its pitch; thus, the longer the tubing, the lower the notes a brass instrument can produce.
- Valves on a brass instrument alter the course of air, causing it to flow through additional tubing, thereby lengthening the airflow column and lowering pitch. In the case of the trombone, this same affect is produced using the slide.
- The bell of a brass instrument influences its sound, in particular helping to efficiently project its sound.
A lip-vibrated instrument consisting of a cylindrical or conical tube produces only a fundamental note and, when vigorously overblown, its natural harmonic series (as, for the fundamental note C: c–g–c′–e′–g′–b♭′ [approximate pitch]–c″–d″–e″, etc.). Most modern brass instruments are provided with valves or slides that alter the length of the tube. This gives the players several fundamentals, each with its own harmonic series, thus making available a full chromatic (12-note) scale. Brass instruments, like all wind instruments, are classified as aerophones.