A method for comparing candidate materials in subjective tests of flat-panel loudspeakers

Flat-panel loudspeakers are often built using a moving-coil or piezoelectric exciter attached to a bending panel that radiates sound, and such devices are finding increased use in TV screens, computer screens, and in sensitive electronics where protection from dust or moisture prevents the use of traditional speaker devices. The overall acoustic response of these speakers is dominated by resonant frequencies which can be calculated from plate parameters such as material, dimensions, and thickness, but each material still has its own unique i'sound” that arises from internal damping rates, non-homogeneity, and other effects that must be measured empirically. As such, many hobbyists and designers are interested in finding the “best-sounding” material for use in flat-panel loudspeakers. In this presentation, a method is outlined for designing plates of various materials with off-the-shelf thicknesses that have near-identical resonances and excursion such that the unique “sound” of each material can be compared in subjective tests. Simulations of and measurements on plates made from acrylic, aluminum, and foamboard demonstrate the effectiveness of the proposed method.