(Fr. embouchure [of clarinets and saxophones, bec]; Ger. Mundstück).
That part of a wind instrument which is placed in or against a player’s mouth, and which, together with the lips or a cane Reed, forms the sound generator.
In brass instruments (including side hole types) it is roughly bell-shaped but is often much modified by external ornament. Internally it has three important elements: the cup (Fr. bassin); the throat (Fr. grain) (or orifice at the base of the cup); and the backbore (Fr. queue) (or expansion) which leads to the main tubing. All three have much influence on the characteristic tone and behaviour of the instrument (see Acoustics, §IV. The cup varies from shallow hemispherical to deeply conical. The throat may be relatively large, small, sharp-edged, rounded off, or, in such as the horn, virtually non-existent. (This applies also to the backbore.) The rim applied to the lips varies according to individual convenience.
In clarinets and the like the mouthpiece is roughly conical externally for some two-thirds of its length, after which it is obliquely chamfered off to a chisel-shaped tip (see Clarinet, fig.3). Opposite the chamfer is a flat table tangential to the surface, and against this the flat reed is placed. The table is slightly curved towards the tip and this ‘lay’ allows the reed to vibrate under the influence of the breath and control of the lips. In the upper part of the table is a rectangular or keystone-shaped slot through to the interior. The internal ‘tone chamber’ may be a simple extension of the main bore of the instrument or it may be enlarged or contracted in various ways which have much influence on the tuning and tone quality of the instrument. Such mouthpieces are today made of wood, plastic, metal or glass.
PHILIP BATE/MURRAY CAMPBELL