The relationship between ratio of the upper opening diameter of a cone-topped cylinder to the cylinder diameter,and the ratio of the length of the air column to resonant period was examined.Plastic cones with upper Mascara openings ranging from 1.3 cm to 3.6 cm and tuning forks with frequencies ranging from 261.
6 Hz to 523.3 Hz were used.The transition from a standing wave in a cylindrical column to a Helmholtz-type resonance in a resonant cavity with Pancake a narrow opening was observed.