Where it all Started
  Now decades later I use a digital tuner for panflutes. I made the 'Middle D' (on the piano) Ultralight Panflute to mimic the natural sound of these delicate reeds, only much lower. I have noticed that a change in moisture and temperature from playing the Ultralight will raise a deep note as much as 70 'cents' --One 'cent' is one 1/100th of a half tone on the digital tuner.
  Since I don't know where these panflutes are to end up, I tune them in a cool room to perfect pitch if briskly blown, which is minus 20 'cents' if softly blown. This way a warmed up Ultralight --or one played in, say, south Texas, won't play too 'sharp.' A note can be lowered slightly by blowing more directly into it than across it. And wobbling the panflute changes the pitch to produce a vibrato effect.