Tin whistle all the holes closed, the whistle generates its lowest note, the tonic of a major scale. Successively opening holes from the bottom upward produces the rest of the notes of the scale in sequence: with the lowest hole open it generates the second, with the lowest two holes open, it produces the third and so on. With all six holes open, it produces the seventh. As with a number of woodwind instruments, the tin whistle's second and higher registers are achieved by increasing the air velocity into the ducted flue windway. On a transverse flute this is generally done by
Low whistle produce a metal replica and Finbar and himself spent many hours in the shed at the back of Bernard's house in Rugby, designing, testing and ultimately perfecting the flute. The first few were named the Furey/Overton flute but when Bernard gave up his job to hand make them full-time, they decided to market them as The Overton Flute. The first resulting instrument was essentially an oversized tin whistle made of copper pipe with a wooden plug but was quickly replaced by the aluminium one. While Overton was unsatisfied with its performance, he subsequently refined the design with an all-aluminium construction,