Index of content:
Volume 107, Issue 2, February 2000
- TRANSDUCTION 
107(2000); http://dx.doi.org/10.1121/1.428265View Description Hide Description
Some issues involved in matching electrodynamic drivers to thermoacousticrefrigerators are examined using an equivalent circuit model. Conclusions are that the driver should be chosen to have a large product the suspension stiffness should be chosen to make the combined impedance of the mechanical and acoustical parts of the system entirely real at the operating frequency; and the piston area should be selected to maximize electroacoustic efficiency, or other desired parameter, by matching the acoustic load to the optimum mechanical load for the particular driver. Alternately, if the piston area is fixed, the operating frequency can be adjusted to make this same match.
107(2000); http://dx.doi.org/10.1121/1.428266View Description Hide Description
A new type of loudspeaker that generatessound by means of the electrostrictive response of a thin polymer film is described. Electrostrictive polymer film (EPF) loudspeakers are constructed with inexpensive, lightweight materials and have a very low profile. The films are typically silicone and are coated with compliant electrodes to allow large film deformations. Acoustical frequency response measurements from (planar dimensions) prototype EPF loudspeakers are presented. Measurements of harmonic distortion are also shown, along with results demonstrating reduced harmonic distortion achieved with square-root wave shaping. Applications of EPF loudspeakers include active noise control and general-purpose flat-panel loudspeakers.