For the last week or so I've been paying particular attention to mouthpiece placement - the top of it used to be down in the red and to my left, and now I've raised it and scooted it closer to centre. I've been working on my lip strength there, and it seems to be somewhat satisfactory - my range is getting back up to a D above high C, but my endurance is still the pits (that'll come with time). However, I've been noticing a disturbing tendency to close up my throat when I run to G above the staff and up. I can feel a lot of tension in my throat whenever I play high, and I know that's not good. I have good reason to believe it's been a habit of mine for a while. Here's the deal: whenever my aperture closes up more, my throat muscles up and it creates a strained tone in the upper register (and here, anything above G on top of the staff refers to "upper register" - I sort of suck, in case you hadn't noticed ). Am I approaching it the wrong way in regards to closing the aperture a little more as I get higher, or is it throat tension that's the problem? Regardless of whether it's the former or the latter, how can I deal with these problems? I've been making good strides in the fields of proper mouthpiece placement and not playing with pressure, but I believe this is still an issue.