On the basis that I can usually lip slur the octave C to high C pretty comfortably and in tune, I've been kidding myself maybe that my range is coming on nicely. But there's a fly in the ointment that niggling me. I can get a nicely resonant top of stave E, but then there's a pronounced jump to a quite sharp non-resonant F. The next few notes are similarly sharp, and it's a real struggle to pull them down. I've not been quick to pick up on it as I'm pretty sure that for a while I've been blowing the lower notes sharp to compensate. I guess there's probably another of those fundamental issues at the root of it, but a couple of pointers would be much appreciated. PS It ain't the trumpet.