The baritone horn, or sometimes just called baritone, is a low-pitched brass instrument in the saxhorn family. It is a piston-valve brass instrument with a bore that is mostly conical, like the flugelhorn and alto (tenor) horn, but is narrower than the conical bore of the euphonium.
The cornet is the leading melodic instrument in this ensemble; trumpets are never used. The ensemble consists of about thirty musicians, including nine B ♭ cornets and one E ♭ cornet (soprano cornet). In the UK, companies such as Besson and Boosey and Hawkes specialized in instrument for brass bands.
On a Trumpet the bore is Cylindrical, having a consistent diameter throughout the instrument, whereas a Cornet has a Conical bore which gradually increases in size down the length of the tubing. This makes a huge difference to the type of sound that is produced with the Trumpet giving a very piercing, direct sound (think Fanfares) and the Cornet a warmer, softer, rounder sound (think Hovis Bread / Coronation street!).
The saxhorn is a family of valved brass instruments that have conical bores and deep cup-shaped mouthpieces. The saxhorn family was developed by Adolphe Sax, who is also known for creating the saxophone family. The sound of the saxhorn has a characteristic mellow tone quality and blends well with other brass.
The tenor horn's conical bore and deep mouthpiece produce a mellow, rounded tone which is often used as a middle voice, supporting the melodies of the trumpets, cornets or flugelhorns, and filling the gap above the lower tenor and bass instruments (the trombone, baritone horn, euphonium and tuba).
The cornet features in the British-style concert band, and early American concert band pieces, particularly those written or transcribed before 1960, often feature distinct, separate parts for trumpets and cornets. Cornet parts are rarely included in later American pieces, however, and cornets are replaced in modern American bands by the trumpet.