The HPSA15 operates within a nominal frequency response range of 400-14,000 Hz, and provides audible output of 120 dB (peak at one meter) at the rated power level. It includes a versatile, three-way, 25/70.7 V line transformer that meets a variety of distributed system needs. The transformer is adjustable by means of a convenient seven-position, watts/impedance selection switch. This labor-saving switch is screwdriver adjustable and includes a protective cover with built-in cable strain relief.