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
Tin whistle apartheid-era townships; the Hohner tin whistle was especially popular in kwela performance. The kwela craze accounted for the sale of more than one million tin whistles. In the late 1950s, mbaqanga music largely superseded kwela in South Africa, and so it followed that the saxophone surpassed the tin whistle as the township people's wind instrument of choice. Kwela master Aaron "Big Voice Jack" Lerole continued to perform into the 1990s; a few bands, such as The Positively Testcard of London, continue to record kwela music. Kwela sheet music is rarely published, and many of the recordings of founding kwela artists