I've posted before saying it seems like sometimes my notes just simply cut out. I think I've honed in on the problem. When I'm playing combinations like 2nd space A down to F down to D, if I play slow enough the F comes out fine because I can adjust/loosen my embouchure (or whatever) so that the F comes out and not the Bb above the A. But when I up the tempo I reach a point where I'm thinking F but my face is evidently thinking Bb, so i miss the F (sounds like a shadowy Bb) then have to force out the D below or just stop altogether. I guess I don't understand what to do to play things at speed. Like a run of A - F - D - F - A etc. at 120 would seem impossible. And similar issues with say A - F# - ... where it wants to play up to B. Thoughts?