The Chalumeau always was considered a shepherd's tool, that needed to be playedsolo. Unfortunately no Chalumeau has survived one assumes that it need to have looked very like a recorderand sounded like the lower octave of latest clarinet. It was tricky to play in tune. Therefore it was uninterestingfor most composers and serious musicians, and was hardly ever utilized in compositions except for some shepherd scenes. The problem developing devices akin to clarinets like the Chalumeau turns into clear in case you think about whathappens if you play an upward scale on an tool like the recorder: There are seven or eight tone holes for the lower octaveas you have got 10 arms and there's an octave hole. "Overblowing" or starting an octave hole makes woodwind gadgets sound exactly one octave higher than the note would sound without overblowing aside from the clarinet, as I will show below. Using the same fingering one time with and one with no an overblowing hole makes the tool sound in different 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 hence rather simple, and it makes things easy for the instrument maker: The tone holes and their distances for the higher octave are precisely an identical as for the lower octave. Now overblowing works on clarinets, too, but the effect is various: The clarinet overblows not to the eighth tone on thescale an octave which 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.