Hello, I'd like to ask some more experienced trumpeters for help with my trumpet playing. Few months earlier I've been given some suggestions from a profesional trumpet player and one of them was playing caruso exercises. After few weeks practicing these exercises I realized that I should probably move my mouthpiece a bit higher because that way I've got much more consistent low to middle register and thought I would learn to use the high register after few months of practice. But after two concerts played this way I've come to a point when I can no more play higher than g over the staff even if I put the mouthpiece back lower on my lips. (when I try to play higher I get only some kind of crackling sound) What would you suggest me to do? Thank you for any replies.