Clarinet, or CLARIONET, a wind-instrument, usually of wood, in which the sound is produced by a single thin reed. It is supposed to have been invented in 1690 by Joseph Christoph Denner, at Nuremberg, though some authorities trace its exist- ence to medieval times. Since its invention it has undergone many changes and improvements, and the modern clarinet, from the extent, quality, and variety of its tone, is one of the most perfect of wind-instruments. The tube of the instrument is cylindrical, ending in a bell, with holes to be covered by the fingers and left-hand thumb; and keys, generally thirteen in number, to supply the additional tones and half-tones.
The mouthpiece is cone-shaped, flattened on one side to form a table for the reed; in the table is a square opening about an inch long and half an inch wide (a in fig.), on which the reed is fastened by the lower and thicker end (b in fig.). The table being slightly curved towards the point, a gap is left between the end of the reed and the mouthpiece; and the sound depends on the vibration of the reed against this curved table. The reed is a thin slip from a tall grass (Arundo sativa) grown in Spain. The clarinet has two principal registers—viz. the lower, called the chalumeau, from E in the bass stave to B♭ in the treble; and the upper, of a different quality, from B♭ treble stave to C♯ above the stave. Another octave higher can be played by cross-fingering, but beyond G the notes are not very effective. The difference between the lower and upper registers is an interval of a twelfth, which gives the clarinet a much greater compass than the flute, for instance, which is an octave-scaled instrument. The upper register is fingered exactly like the lower, except that the B♭ key (the highest on the tube, c in fig.) is kept open by the thumb of the left hand. The Boehm modification of fingering (see FLUTE) has been applied to the clarinet, but is not so suitable to it as to octave-scaled instruments.
The ordinary difficulties of the fingering are so much intensified in playing in keys with many sharps or flats, that in orchestras it is usual to have instruments of different pitch to simplify the key. These are usually the A♯, B♭, and C clarinets, though the latter is gradually going out of use.
In military reed-bands the B♭ clarinet is the leading instrument, with the addition of one or two smaller clarinets in E♭ to assist in the sharper passages (see BAND). Clarinets in various other keys have been introduced but seldom used.
Mozart, Beethoven, Mendelssohn, Weber, Meyerbeer, Spohr, and Rossini have made extensive use of the clarinet in their orchestral compositions, though some of the parts written for the instrument, especially in the overtures to Semiramide, Otello, and Gazza Ladra by Rossini, are so difficult as to be almost unplayable.
A tenor clarinet, known as the Basset-Horn (q.v.), is also used in orchestral music. The Bass Clarinet is an instrument of the same construction as the ordinary clarinet, an octave lower, usually pitched in B♭. It is also used in orchestral and military bands.