The family of brass instruments includes all those that are sounded by the vibrations of a player’s lips. Though not all are actually made of brass, the majority of instruments in the family are made from metal alloys coated with a shiny lacquer.

Brass instruments differ less in their construction than the woodwind family. Like their cousins, they make use of both conical and cylindrical bores but very often both are used in one instrument. The major revolution in brass-instrument design was the invention of the valve in the early-nineteenth century.

Columns of Air

All brass and woodwind instruments employ enclosed columns of air and rely on the properties of the harmonic series (the simultaneous pitches generated by the vibrations of air) combined with methods of altering the length of the air column to sound different pitches.

The lowest note a given column of air can sound is known as the ‘fundamental’. At the same time as the fundamental, higher notes also sound. These are known as overtones and are precise multiples of the fundamental. The first overtone vibrates twice as fast as the fundamental, the second three times as fast, the third four times as fast, and so on. In musical terms, this translates to the first overtone being an octave higher than the fundamental, the second a perfect fifth higher, the third a fourth higher, continuing in ever-decreasing steps. Each of these overtones (also known as partials) can be made to sound most prominent by increasing the amount of energy put into the air column, an effect known as overblowing.

Shape

A significant part of brass-instrument design, therefore, is the creation of a stable column of air that has acoustic properties able to help with sound production. The most useful shapes for brass (and woodwind) instruments are the cylinder and the cone.

In practice, most modern brass instruments are a mixture of the two: it is the extent to which a cone widens and the length of the tube that are largely responsible for the instrument’s character. The potential difference can be heard by comparing a trumpet to a flugelhorn. The former – cylindrical except for the mouthpiece shank and the flared-bell section – has a bright, clear sound. The latter – conical except for the tuning shank – has a mellow, dark sound.

Early Brass

The earliest trumpets and horns were simple tubes. They could sound only the pitches common to their fundamental pitch. To play higher, more energy was needed, which was tiring for the player. Gradually the tube’s construction improved, making sounding the higher partials easier, until it was possible to play a complete diatonic scale.

Western music since the Renaissance has largely been organized using a system called ‘equal temperament’, which divides the octave into 12 equal steps called half steps (or semitones). Although based on the properties of the harmonic series, equal temperament in fact irons out inconsistencies that occur with increasing regularity in the higher regions of the series. Consequently,...

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