I regularly have days when for some reason, I just can't play worth a damn. Trying to play soft results in nothing coming out of the horn, and when I get it to make a sound it's a very awful airy and buzzy sound. If I'm just practicing normally, I tend to get frustrated and put the trumpet away for the night. Unfortunately, this has happened at more than one rehearsal, and even during a concert. I don't feel that on this "off nights" I'm doing anything differently, and have no real explanation for why it happens. Does anybody have ideas as to what causes this horrible sound and/or ability to play softly and relaxed? Perhaps a suggestion as to how to remedy or avoid it?