I used DRA Labs’ MLSSA system, a calibrated DPA 4006 microphone, and an Earthworks microphone preamplifier to measure the Tannoy Stirling Prestige Gold Reference’s frequency response in the farfield. I used an Earthworks QTC40 mike for the nearfield responses and Dayton Audio’s DATS V2 system to measure the impedance magnitude and electrical phase angle.
The Stirling’s anechoic sensitivity is specified as a high 91dB/2.83V/m. My B-weighted estimate was even higher, at 93.8dB(B)/2.83V/m. Tannoy specifies the Stirling’s impedance as 8 ohms, with a minimum magnitude of 5 ohms. My impedance measurement (fig.1, solid trace) varied between 5 ohms and 8 lies under 3 ohms below 37Hz, between 96Hz and 156Hz, between 1.4kHz and 1.8kHz, and above 3.5kHz. The minimum effective resistance is 2.4 ohms at 115Hz, 2.3 ohms at 1.58kHz, and 1.825 ohms at 6.5kHz. The Stirling will work best with amplifiers that don’t have problems driving low impedances, though the speaker’s high sensitivity will reduce its need for current.
