A cornet resembles and can play all the same notes as a trumpet. The key difference is in the bore, or tubing. While a trumpet bore is cylindrical, or the same diameter from mouthpiece to bell, a cornet bore is conical, gradually widening throughout the length of the instrument, resulting in a warmer, mellower sound. To cater to all musical and aesthetic tastes, brass instrument manufacturers offer dozens of subtle variations on the cornet.
The standard cornet is pitched in B-flat, but cornets are manufactured in other pitches. When very high notes are called for, a C or E-flat ("soprano") cornet may be used. Other pitches of cornet exist, but are very rarely manufactured or used in performance, because other brass instruments fill those pitch ranges.
Cornet bores range from 0.410 to 0.485 inches in average diameter, with 0.453 to 0.464 being the most common bore size. The smaller bores are easier to play, with a more piercing, bright sound. The larger bores require greater breath control and pitch accuracy on the part of the musician, and carry a more expansive, complex tone.
Shepherd's Crook (Or Not)
There are two basic shapes of cornet. One is the classic "shepherd's crook," which has a broadly curving section of pipe on the end near the musician. Cornets with a shepherd's crook tend to carry a warmer, "rounder" sound. The other shape of cornet is more like a trumpet, lacking the shepherd's crook. The trumpet-style cornet is best suited for large ensembles and orchestras in which a brighter tone is required for the cornet to be heard among the other instruments.
There are two basic cornet valve systems: piston and rotary. Piston valve cornets, the more common of the two systems, have pistons with holes in them that go up and down inside a cylindrical casement. The holes shift the air column to secondary sets of tubing, thus lengthening the air column and lowering the pitch. The rotary valve cornet accomplishes the same function, but rather than going up and down, the valves rotate to send air through the secondary pipes.
The wrap of a brass instrument is the general shape in which the pipes are coiled into a compact shape. There is little major variation among cornet wraps, but subtle variations between makes and models can affect tone qualities. The only way to notice the differences in tone quality is to play the cornets themselves.
Cornet mouthpieces come in a range of sizes and shapes. They all follow the basic cup-and-shank shape, but the depth of the cup and the length of the shank can produce different tone qualities. For example, the shallower the cup, the brighter the tone, and the deeper the cup, the warmer the tone.
Cornets can be finished in brass, silver, gold or copper, with either a buffed patina or a lacquer sheer. Manufacturers add their own visual flourishes to the finish of their cornets.
At least a dozen major brass instrument manufacturers produce cornets, including B&S, Bach, Besson, Blessing, Conn, Courtois, Getzen, Jupiter, Kanstul, King, Prelude, Stomvi, Weril, Yamaha and York. Each manufacturer offers its unique take on the cornet. Some of them produce more variations than others. Getzen, for example, offers at least six models of cornet.
Due to its long evolution, there are more variations on the cornet than can ever be categorised. One odd cornet is the "mute cornett" (note the two t's), which is a non-wrapped wooden pipe with holes in it to be keyed like a recorder. The musician buzzes into the mouthpiece as would a modern cornet, and the instrument carries a similar range of notes. Most people would not consider this to be a true cornet, but it is related.