This is a question about "throat tones" for clarinet players. I'm reading an orchestration book that says "very rapid passages across the break should be avoided". It describes the "break" between the middle and clarino register as being between Bb and B (written). But the illustraion shows the written range of G to C on the staff. So, I'm wondering exactly what they mean. Do they mean not to write passages that involve going from Bb to B and vice versa, or do the same "rules" apply to other notes in the middle register? And how hard and fast is this rule? Can a good player manage this without much trouble? Or does the length of the passage and the frequency of these notes in it make a difference? Is this less an issue with the Bass Clarinet or Eb Clarinet?
Another book says that fast legato passages in the throat tone range should be avoided. I have a piece with a theme based on an arpeggio that encompases some of the middle register. It is played moderately fast the first time it occurs and faster on its second appearance. I currently have scored it for the keyboard, but I'd like to have it played on the clarinet because there are answering phrases in the flute. It goes too low for the oboe, in one section and too high for the English Horn in another and there isn't enough time to switch. So, it has to be the clarinet if played by a reed. I tried using an alto sax, which is good for the range, but it has way too much color and the keyboard doesn't have quite enough. (I tried organ and harpsichord patches.) Laying aside for a moment the idea that if I looked hard enough I might be able to find a sax or keyboard instrument that I like better, I'd like to know if the clarinet would work because it sounds like just what I'm looking for, but I'd hate to give a clarinet player something that won't be played well because it isn't what he's used to doing in this range.