See F. G. Rendall, The Clarinet 3d rev. ed. 1971. If you're having trouble with notes from the 1st B over the break and up, then the problem may be loads of things. If they aren't speaking at all, you might want to try tightening up a little bit, in order that the reed
could be in a position to vibrate more. If your embouchure is already very tight, then that you would be able to loosen up, also to assist the reed vibrate more. It would also help so that you can move the reed down to your mouthpiece. You could try a smaller
size reed ex. if you're on a 2 1/2, use a 2, particularly if when you try to play, the air seems to pass right under the reed.