An acoustic study of ceramic traditional whistles

Abstract

Ceramic whistles are very common all along the old European traditions. Gifts, decoys or simple decorative objects these whistles may have extremely various shapes: animals, tea-pots and sometimes flutes. Even with this extremely variability, their interior shapes are very similar: a channel where to blow, an edge and a small cavity. Some of them produce a single sound when others present one or more tone holes, the later corresponding mainly to flute shaped whistles. Their acoustic behaviour appears to be very simple: Helmholtz resonators or flutes driven by the common non linear excitation system. Nevertheless some are known as water whistles and sometimes as "nightingales". The acoustic study presented will first verify that the simplest whistles are really working as Helmholtz resonator with the noticeable exception of the flute shaped ones that remain whistles for the organologist but are a different object for the acoustician. Then a particular attention will be given to the "nightingales" ones. Their sound production will be related to the level of water they contain and the modulation of the acoustic signal analyzed in terms of coupling between the oscillation of the water and the Helmholtz acoustic resonance. © 2013 Acoustical Society of America.