Noun
(music) A woodwind instrument which was the predecessor of the clarinet.
The lowest range of the clarinet, reaching up to written B♭ (B flat) above middle C.
Source: en.wiktionary.orgAround the turn of the 18th century, the chalumeau was modified by converting one of its keys into a register key to produce the first clarinet. Source: Internet
As clarinets improved, the chalumeau fell into disuse, and these notes became known as the chalumeau register. Source: Internet
The chalumeau register is rich and dark. Source: Internet
The chalumeau register plays fundamentals, whereas the clarion register, aided by the register key, plays third harmonics, a perfect twelfth higher than the fundamentals. Source: Internet
The low (chalumeau) register of the clarinet spans a twelfth (an octave plus a perfect fifth), so the clarinet needs keys/holes to produce all nineteen notes in that range. Source: Internet
This "hourglass" shape, although not visible to the naked eye, helps to correct the pitch/scale discrepancy between the chalumeau and clarion registers (perfect 12th). Source: Internet