MEASUREMENTS

I measured the Alta Audio Alyssa’s farfield behavior with DRA Labs’ MLSSA system and a calibrated DPA 4006 microphone. I used an Earthworks QTC-40 mike for the speaker’s nearfield responses. A full set of measurements was performed with serial number ALY4004. I repeated some of the tests with serial number ALY4003. Other than when noted, the magnetically attached grille was left off for the measurements.

Alta specifies the Alyssa’s sensitivity as 87.5dB/2.83V/m. My estimate was significantly lower at 81.5dB(B)/2.83V/m, and the Alta did sound a little quieter than the BBC LS3/5a that I always measure at the paper by Eric Benjamin to calculate what UK writer Keith Howard has called the “equivalent peak dissipation resistance” (EPDR, footnote 1). The Alyssa has minimum EPDRs of 1 ohm at 31Hz, 64Hz, and 128Hz, and the EPDR remains between 2 and 3 ohms in the midbass and midrange. The Alyssa needs to be used with amplifiers that are comfortable driving loads below 4 ohms.