Why Do Trumpets Announce Things? Loud, Outdoors and Unmistakable

The function is to command attention across a distance and over a crowd, outdoors, without amplification, which is a demanding requirement met by very few instruments. Brass instruments are the loudest thing available, carry well in the open, and have a timbre that is unmistakable and that no other sound resembles. The message is that something is beginning rather than any content, so length is unnecessary and brevity is an advantage, since a long piece would lose the attention it gained. The result is a form that is loud, short, rhythmically emphatic and repeated, and those properties have been stable for as long as the instruments have existed.

The characteristic shape comes from a physical constraint:

• •A brass tube without valves sounds only the notes of its natural series
• •Those notes are widely spaced at the bottom and closer together higher up
• •A melody was therefore only possible in the upper register
• •The available notes at usable registers outline a major chord
• •So the music consists of leaps around a chord rather than stepwise lines
• •Dotted rhythms and repeated notes fill the gaps between those leaps

The applications were practical before they were ceremonial. Military signalling used specific calls to convey orders across a battlefield where the voice could not reach, with a repertoire of calls that troops learned and that persists in bugle calls still used for daily routine. Hunting used calls to coordinate a field spread through woodland, with a vocabulary indicating what quarry had been found and what stage the hunt had reached. Heralds announced arrivals and proclamations. Town watches and coaches used horns. The ceremonial use grew directly from these, since a sound that had meant an important arrival for centuries carried that association whether or not anybody needed the information.

Fitting valves from around 1815 gave brass instruments every note and changed their role entirely, which makes the older repertoire sound the way it does for reasons that no longer apply. A valved instrument can play melodies in any key and in any register, so composers gave brass parts that would have been impossible before, and the instruments moved from signalling and reinforcement into full melodic participation. The natural instruments did not disappear, being retained for military and ceremonial use where the limited set of notes is exactly what is wanted, and the bugle used for daily calls has no valves to this day. Players performing older music on period instruments face the original constraint deliberately, which is why those performances sound different.

The style became a recognisable gesture that composers use to mean something rather than merely to announce. Opening a piece with one signals that a formal or public utterance is beginning, and the gesture is used ironically as often as sincerely. Monteverdi opened an opera with one in 1607. Purcell, Handel and Bach all used the style, with Bach writing extraordinarily demanding high trumpet parts in exactly this idiom. Nineteenth century composers used it for military and heroic associations. Aaron Copland wrote one in 1942 as a standalone concert piece that became enormously well known. Film scores use the gesture constantly, and it remains legible even to listeners who have never heard a herald.

The requirement is to command attention outdoors across a crowd without amplification, which brass instruments meet and almost nothing else does, and brevity keeps the attention gained. A tube without valves sounds only its natural series, whose usable notes outline a chord, which is why the style leaps around chords with dotted rhythms. Military signalling, hunting and heralds came first and the ceremonial use grew from them.