I just received my tenor recorder (courtesy of Music.SE :D) and I was playing around in the upper range. I noticed that once I get up to the high C and beyond (no pun intended), the notes come out an octave low. I can get the high C out by really blowing hard, but I can't get the high D out for the life of me.
I've noticed this same thing in my alto, but it is not nearly so hard to play the upper range. It only needs a little extra effort. However, the tenor is just impossible.
Is this a glitch in the recorder, or do I need to do something differently? I've tried blowing harder and pinching the thumb differently, but I can't get it out.