Abstract: A golf club has an air flow hole through its head and the hole contains a whistle so that when the club is swung, the sound of the whistle provides an indication of the smoothness and velocity of the swing. The ambient air becomes locally turbulent at the hole's outlet end when the head swings. A tailpipe extends from the hole's outlet to a position where the ambient air is relatively free from such turbulence. The club head may include two whistles. The first whistle is actuated by air entering an aperture on the striking face of the club head. The second whistle is actuated by centrifugally driven air moving down the club shaft.