A traditional “glass harp” is an array of wine glasses filled to various depths. We discovered that a single empty wine glass submerged in a bath of water can also be used as an instrument. This new “inverted glass harp” allows realtime pitch modulation, giving musicians the option for glissandos or vibrato. Here we derive and validate scaling laws for the resonant frequency of wine glasses in the general case where liquid is inside the glass, outside the glass, or both. (This work is from PI Quinn’s research prior to the SFS Lab and is archived here for reference.)
Authors: Daniel Quinn, Brian Rosenberg
Abstract: We present an analytical treatment of the acoustics of liquid-filled wine glasses, or “glass harps.” The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the “inverted glass harp,” in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace’s equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions.