Something I have always struggled with is playing loud. Yes, I could say "playing loudly", but there seems to be a whole different mindset, even a culture, that goes along with playing at high volumes. So in my mind, it's not just a modifier of one's playing (i.e. the adverb "loudly"), but a modifier of the type of music being played and the style.
Anyway, that's a completely different topic than I want to talk about today. The point is that I came across a very nice handout by Alastair Kay from a Yamaha clinic in 2002. On this handout are a couple of exercises for playing both loud and soft, as well as some excellent pointers about the shape of the lips in each dynamic. I've been trying to find that "burn" in my sound for a few days now (much to the chagrin of my neighbors), and although it cracks around the edges especially when articulating, I am already starting to think more about how I play loud rather than just expelling as much air as possible through the horn.
Excellent, excellent resource.