WHILE the instruments of the oboe family have two bits of reed in their mouthpieces, the clarinets have only one. This is a broad strip, narrowing at the top to a very sharp edge. It is attached to the mouthpiece of the instrument by two metallic bands provided with screws. The player presses the end of the reed against his lower lip while performing, and the vibrations of the reed cause the air-column in the tube to vibrate also, and produce the tone.
The early instruments known as shawms, and probably some of the old Greek auloi, were of this type. But the clarinet as we know it is due to Johann Christopher Denner, of Nuremburg, who perfected it in 1690. This instrument was improved by Stadler, of Vienna, and by Sax, of Paris; but it is not suited for the Boehm system of keys. The main part of its tube is cylindrical, which has some effect; but the size of the reed is really responsible. While the flute and oboe act like open pipes, the clarinet behaves like a stopped pipe, closed at one end. One result is a deeper pitch, the clarinet sounding an octave below a flute of the same size; while another effect is found in the fact that stopped pipes do not give the odd- numbered harmonies. This point is explained in the chapter on "Acoustics." The first harmonic, an octave above the normal tone in pitch, is used to get a second octave scale in the flute or oboe; but it does not exist on the clarinet. The over-blowing in the latter case causes the air-column to vibrate in thirds instead of halves, giving a rise in pitch of a twelfth instead of an octave. Thus a fingering based on octaves must be supplemented in some way.
The clarinet (German, Klarinette; French, clarinette; Italian, clarino) has six finger-holes, played by three fingers on each hand. These give the scale of G major, a fifth below that of the flute. There are extra keys to close holes at the end away from the mouthpiece, thus lengthening the air-column and lowering the compass to the E below middle C. The usual keys for sharps and flats are