MEASUREMENTS

I used DRA Labs’ MLSSA system and a calibrated DPA 4006 microphone to measure the Dynaudio Confidence 30’s frequency response in the farfield, and an Earthworks QTC-40 mike for the nearfield responses. I measured the speaker’s impedance with Dayton Audio’s DATS v2 system.

Dynaudio specifies the Confidence 30’s sensitivity as 88dB/2.83V/m; my estimate was within experimental error of that figure, at 87.5dB(B)/2.83V/m. The Confidence 30’s impedance is specified as 4 ohms with a minimum magnitude of 2.8 ohms at 85Hz. The impedance magnitude (fig.1, solid trace) remains above 8 ohms drops below 2 ohms between 53Hz and 101Hz and between 228Hz and 372kHz. The minimum EPDR value is 1 ohm from 68Hz to 80Hz and 1.28 ohms at 279Hz. The Confidence 30 should be used with amplifiers that don’t have problems driving impedances of 4 ohms or lower. The shape of the impedance magnitude trace suggests that the Dynaudio’s high frequencies will be emphasized if the loudspeaker is used with tube amplifiers that have a high output impedance.