slow air blow, make the base frequency sound (lowest note of same shape opening)
fast air blow (faster enough to meet required speed), make octave higher note for the same shape opening
so if you blow fastest, you may reach even higher octave
a open hole make sound flow end exits early, and achieve a higher pitch sound compared to before
a half open hole make the effect of exiting less, and the pitch is inbetween close and full open
a hole near end tip more, make lower sound
a hole near mouse tip more, maker higher sound
slight shift hole towards end tip, make pitch slightly lower
a smaller hole also maker pitch slightly lower
with combination of techniques of adjust hole position and size, you can move the desired hole when design the recorder to hit the same note.
the back hole also help shift the note pitch.
