So the intensity of your picking hand, such as how hard you pick the string is a direct contributor of getting that clean sound of each hammer on? Wow, I'm finding that the simplest things are the answers to all my questions. It seems so simple; I can't believe I didn't think of it before. I've been studying theory, memorizing scales, playing everything I can get my hands on, and this is the shining light I've been looking for: pick the string harder. Thanks guys!