Hi Johnelwood – I picked up on your “letting the air escape the aperture with the tension in the corners surrounding the aperture ” I pride myself with playing with less tension (ie not over blowing) but just now I took your advice.. plenty of air.. tension around the enbouchure.. but then just almost playing with my mouth open – no concept of blowing – and a high c came out very open easy and full..
good tip !
thanks steve