Acarian Systems Alón Circe loudspeaker Measurements part 2
Fig.4 Alón Circe, response at 50" of woofer without crossover (top) and with (bottom), both curves corrected for microphone response.
Fig.5 Alón Circe, response at 50" of midrange unit without crossover (top) and with (bottom), both curves corrected for microphone response.
Fig.6 Alón Circe, response at 50" of tweeter without crossover (top) and with (bottom), both curves corrected for microphone response.
A similar effect can be seen in both the equalized and raw responses of the tweeter (fig.6). Note that the HF unit is still putting out significant energy for two octaves below its nominal passband, due to the crossover's slow-slope high-pass filter. This can also be seen in fig.7, which shows the Circe's overall acoustic crossover. The crossover between the woofer and midrange appears to lie almost an octave higher than specified. While the midrange unit and tweeter do cross over at the specified 3.5kHz, there is significant overlap. The sharp dip and peak at 26kHz in the tweeter's output are due to the resonance mentioned earlier. The peak between 40Hz and 60Hz is due to the woofer tuning, with a 12dB/octave rolloff apparent below that region.
Fig.7 Alón Circe, acoustic crossover on tweeter axis at 50", corrected for microphone response, with the nearfield woofer and midrange responses plotted below 355Hz and 600Hz, respectively.
Fig.8 shows how these individual responses add up on the tweeter axis at a distance of 50". The shape of the curve is basically triple-humped, with peaks and dips roughly 4dB either side of the median line, and the suckout in the high midrange most pronounced. How this response will be perceived is hard to predict, as it will depend very much on the music program whether the listener notices peaks as excesses in energy or the dips as energy deficiencies. In my own auditioning, when the speakers were being driven by the Cary amplifiers I kept latching on to the octave-wide plateau between 500Hz and 1kHz, which I felt added a slight megaphonelike quality to the balance. On the plus side, it will emphasize recorded detail.
Fig.8 Alón Circe, anechoic response on tweeter axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response, with the nearfield woofer response plotted below 300Hz.