About Johann Denner
Denner was a master maker of flutes, oboes and bassoons, infact he often mused over the puzzling mystery of why the chalumeau would not “overblow” to the octave as would the flute, oboe and bassoon. Denner thought if he could extend the compass of the instrument upward he could make a valuable instrument.
Johann soon determined that this instrument did not over-blow to the octave but to the twelfth i.e. when all the finger holes were closed and the lowest note (fundamental) was sounded, the next note could be produced by increasing the blowing pressure. Thus was the note a twelfth above, and not an octave. Example: low G overblown would be a D, twelve notes above the G. Denner also discovered that this note was produced much easier if he bored a little hole higher up on the instrument near the mouthpiece. This became the “speaker or register key,” and in fact, did make over-blowing to the next register much easier.
Johann Christoph Denner, (born Aug. 13, 1655, Leipzig [Germany]—died April 20, 1707, Nürnberg, Bavaria), German maker of musical instruments and inventor of the clarinet.
Denner’s father, Heinrich, made horns and animal calls; from him Christoph learned instrument building, at the same time becoming an excellent performer. His energy was mainly devoted to improving already existing woodwind instruments, and his well-tuned recorders, flutes, oboes, and bassoons were highly regarded throughout Europe. He invented the clarinet sometime between 1690 and 1700, although other types of single-reed instruments had a long history and wide currency, especially in folk music. One of these, the chalumeau (a term also used for a double-reed instrument), was known to Denner; apparently his attempts to refine the chalumeau led to his invention of the clarinet. Denner’s two sons continued the family tradition of instrument building.
For more about Johann Christoph Denner visit Britannica.com