I used DRA Labs’ MLSSA system, a calibrated DPA 4006 microphone, and an Earthworks microphone preamplifier to measure the Triangle Antal 40th’s behavior in the farfield. I used an Earthworks QTC-40 microphone for the nearfield responses. This mike has a ¼ "-diameter tip, so it will not obstruct the radiation from the driver diaphragms or port.
The Antal 40th’s anechoic sensitivity is specified as a high 92dB/W/m. My B-weighted estimate was 3dB lower, at 89dB(B)/2.83V/m, though this is still higher than average. Triangle specifies the Antal 40th’s impedance as 8 ohms, with a minimum magnitude of 3 ohms. Using lies below 2 ohms between 66Hz and 145Hz and between 180Hz and 645Hz, and the minimum value is 1.11 ohms at 93Hz. While, to some extent, the drive difficulty will be ameliorated by the moderately high sensitivity, the Antal 40th will work best with amplifiers that don’t have problems driving low impedances.
