MEASUREMENTS

I used DRA Labs’ MLSSA system and a calibrated DPA 4006 microphone to measure the Stenheim Alumine Three’s frequency response in the farfield and an Earthworks QTC-40 mike for the nearfield responses. (I measured serial number 20030028.) Owing to the Alumine Three’s weight—approximately 154lb—I wasn’t able to lift the loudspeaker as high off the ground as I like to do for the farfield measurements. As this meant that the reflections of the speaker’s output from the floor were closer in time to the direct sound, I had to window the impulse response data more aggressively than usual, which reduces the midrange resolution of the FFT-derived frequency responses.

The Alumine Three’s sensitivity, measured in half-space and without any weighting, is specified which gives a closer correlation with a loudspeaker’s perceived loudness than an unweighted figure. The Alumine Three’s B-weighted sensitivity was 91dB/2.93V/m, which is still significantly higher than average.