Hello, I'm a newbie to this forum. I am a sophomore in high school and have been playing trumpet since the 4th grade; I took lessons briefly in 7th grade through mid-8th grade, then quit private lessons due to a schedule conflict. I have not been in a lesson ever since, for about a year and a half. I believe I have embouchure problems, and I came here to see if anybody has any tips on making it consistent. My problem (it might take a while to get to the real problem, as I'll try and explain every detail.): I start off my warm up every time, except for few moments in school band when I have no time to do my personal warmup. Before warming up, I do some lip buzzes first to warm up my chops a little. My warmup starts with a low C, and then I try and warm up my horn by going down chromatically to the lowest F# and back up again, and repeat it a few times. I then play some intervals (page 125 of Arban's) before going into some flow exercises and the Cichowicz flow. After that I do some flexibility exercises before going into my ensemble and orchestral music work. Overall my warmup is around 10-15 minutes. My problem is that the first few minutes of playing an orchestral piece (1st mvt of the Hummel, for example) my chops work just fine, sometimes great. My embouchure structure is fine. But as soon as 10 minutes into my practice, my embouchure seems to "collapse." Literally, it seems to collapse; my upper lip goes into a funny position and juts forward, and I have a habit of pulling my lower jaw backwards when going into fatigue. In that state my embouchure goes bad by just playing long tones on high Es, or the Es on the staff. Air constantly leaks out from the edges of my embouchure and it gets really hard to play. Is this just an endurance/stamina problem, or is it something fundamentally wrong with the position of my embouchure? Here are two pics of my embouchure: 1. Middle G: Normal embouchure, no air leaking, upper and lower lips in "correct" (at least, what I believe is correct) position Image - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting (no virus, I promise) 2. High E: Air leaking, lower jaw comes in and upper lip juts out. Stamina problems. Image - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting (Sorry, it is difficult to take front-view photos with a computer webcam.) If anybody has any ideas I would very much appreciate it. I will go and ask my band director tomorrow as he is an extremely experienced trumpet player. Thanks for any help!