During my lesson tonight, going through Clarke's 2, slured and single tongued - the sound was fine, but double-tongued, it sounded horrible. My teacher said I was "playing under the notes" I could not identify it as such, it just sounded lousy. This for notes below C under the staff, or maybe below B, but you get the idea, at the low end F#, G, G#, A . . . What's the cause of that . . . He seemed to think it was "support," but I'm not so sure. Any anyway, I guess his cure is for me to just work it . . . I'm wondering if I should work it with a tuner, or just listen, it's bad enough that I can certainly hear it without a tuner . . . Is this a common problem?