MEASUREMENTS

I used DRA Labs’ MLSSA system and a calibrated DPA 4006 microphone to measure the PSB Synchrony T600’s frequency response in the farfield. My reference axis for the measurements was level with the center of the midrange unit, which is 38" from the floor, slightly above the height of my ears in my listening chair. I used an Earthworks QTC-40 mike for the nearfield and in-room responses and Dayton Audio’s DATS V2 system to measure the impedance.

PSB specifies the Synchrony T600’s anechoic sensitivity as 89dB, presumably for 2.83V at 1m. My B-weighted estimate was slightly lower, at 87dB(B)/2.83V/m. The Synchrony T600’s nominal impedance is specified as 4 ohms—also the specified minimum impedance. The solid trace in fig.1 indicates that the impedance magnitude lies between 4 and 6 ohms over most of the audioband, with minimum values of 3.26 ohms at 39Hz drops to 1.8 ohms at 35Hz, and to 2 ohms between 74Hz and 85Hz, and between 2.3kHz and 3.1kHz. The Synchrony T600 must be used with amplifiers that don’t have problems driving 4 ohms. Fig.1 was taken with the loudspeaker’s three reflex ports open. With them closed, the impedance was the same above 70Hz but now there is a single peak in the bass, centered on 46Hz (fig.2).