John thank you so much for such an enlightening post. My range at the moment is F on top of the staff. Yes I can play the G but its weak. The notes above that to high C are just starting to speak. However I’m really interested in the fact that you have latched onto passive air. This is something I think I am going to concentrate more on. My feeling is that my control of the aperture corners is not refined enough and thats way I am struggling to extend my range to high C. I have been supporting my air, trying to avoid mouthpiece pressure and thinking of using less as I go up but thats really hard to do. Passive air however is just a release and so at least should be consistent. I will start tomorrow on practising using passive air and try to concentrate on the corners. As you said in another post “less is more” Think I am being too crude in operation if you know what I mean. I understand the concepts, they make perfect sense to me. Great to hear that you can now play a high C on passive air, enforces what Greg says that its possible.