MEASUREMENTS

Iused DRA Labs’ MLSSA system and a calibrated DPA 4006 microphone to measure the Bowers & Wilkins 705 Signature’s frequency response in the farfield, and an Earthworks QTC-40 mike for the nearfield and in-room responses. I measured the impedance with MLSSA, checking the results with Dayton Audio’s DATS V2 system. I used the formula in a 1994 JAES paper by Eric Benjamin to calculate with Microsoft Excel what UK writer Keith Howard has called the “equivalent peak dissipation resistance” (EPDR).¹

Bowers & Wilkins specifies the 705 Signature’s sensitivity as 88dB/2.83V/m; my estimate was within experimental error of that figure, at 87.6dB(B)/2.83V/m. The 705 Signature’s impedance is specified as 8 ohms. The impedance magnitude (fig.1, solid trace) stays above 8 ohms