Phase Technology PC80 loudspeaker Follow-Up Measurements
Fig.1 shows the PC80's FFT-derived anechoic response, measured over a 30° lateral window with the grille on. The 2.5kHz peak is still apparent, but is lower in amplitude than that seen in my original measurement made with the grille off. This suggests, as I stated in the PC80 review, that the grilles should be left on for listening.
Fig.1 Phase Technology PC80, anechoic response on tweeter axis at 45" with grille on, averaged across 30° horizontal window and corrected for microphone response, with the complex sum of nearfield woofer and port responses plotted below 300Hz.
Fig.2 is the FFT-derived 1/3-octave–smoothed in-room response of the PC80/PC90 combination, measured at seven points near the listening position and averaged to reduce the effects of room-induced anomalies. Although the dip at 60Hz and peak at 80Hz are room effects (they also appear on the Muse Model 18/Hales Signature in-room response in Vol.14 No.7), the range below 300Hz is a little lumpy in relation to the Muse/Hales plot. There is also less energy in the three octaves between 100Hz and 800Hz, along with a greater dip in the lower treble.—Robert Harley
Fig.2 Phase Technology PC80/PC90, spatially averaged, 1/3-octave response in RH's listening room.