Commercial loudspeakers were made practical for laboratory thermoacoustics
by placing one in the cold end of the resonator [S. R. Murrell and G.
Mozurkewich, J. Acoust. Soc. Am. 94, 1772(A) (1993)], but the efficiency of such
devices suffers from the opposed directions of traveling wave/standing wave heat
pumping effects and from additional thermal loads at the cold heat exchanger.
Efficient designs using drivers at the higher temperature end typically require
special materials and fabrication. In the proposed compliant configuration, a
driver with mechanical resonance below the operating frequency (which is typical
of available loudspeakers) is placed close to the ambient heat exchanger and the
volume backing the driver is tuned to achieve resonance and a high electrical
efficiency. Numerical results show that the current xBL product can be as little
ASA 132nd meeting - Hawaii, December 1996