Unfortunately no Chalumeau has survived one assumes that it should have looked very like a recorderand sounded just like the lower octave of modern-day clarinet. It was not easy to play in tune. Therefore it was uninterestingfor most composers and critical musicians, and was hardly used in compositions other than some shepherd scenes. The problem developing gadgets corresponding to clarinets just like the Chalumeau turns into clear when you think about whathappens if you play an upward scale on an instrument like the recorder: There are seven or eight tone holes for the lower octaveas you have gotten 10 fingers and there is an octave hole. "Overblowing" or establishing an octave hole makes woodwind gadgets sound precisely one octave higher than the note would sound with no overblowing other than the clarinet, as I will show below. Using an analogous fingering one time with and one with out an overblowing hole makes the device sound in alternative hights; during this contents you speak of lower and upper sign in. So you actually need seven tone holes and an overblowing hole. Learning how to play higher registers on woodwinds like a recorder is therefore rather simple, and it makes things easy for the instrument maker: The tone holes and their distances for the higher octave are accurately an identical as for the lower octave. Now overblowing works on clarinets, too, however the effect is different: The clarinet overblows not to the eighth tone on thescale an octave that is exactly double the frequency but to the 12th tone. The Italian word for here's duodecime,and so we call the overblowing key the duodecime key. A amateur must learn this and get used to it.