Frequency response (at 2 meters)
front left/right: 100 Hz to 20 kHz ±2.7 dB
center: 100 Hz to 20 kHz ±2.7 dB
surrounds: 100 Hz to 20 kHz ±2.9 dB
subwoofer: 40 to 117 Hz ±2.2 dB
Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input)
front left/right/center: 89 dB
surrounds: 86 dB
front left/right/center: 3.6/6 ohms
surrounds: 3.8/9 ohms
Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room)
front left/right/center: 80 Hz at 78 dB
surrounds: 80 Hz at 73 dB
subwoofer: 25 Hz at 80 dB SPL
87 dB average SPL from 25 to 62 Hz
106.5 dB maximum SPL at 62 Hz
bandwidth uniformity: 82%
Left, Right, Center, Surrounds
All of the curves in the frequency-response graph are weighted to reflect how sound arrives at a listeners ears with normal speaker placement. The curve for the left/right front channels reflects the CD 250's response averaged over a ±30-degree window, with double weight at 30 degrees (the most typical listening angle). The center-channel curve reflects the CD 250's response when mounted horizontally, averaged over ±45 degrees with double weight directly on-axis. The surround-channel curve shows the CD 220's response averaged over ±60 degrees. These measurements were taken at a full 2 meters, which emulates a typical listening distance, allows each speaker's output to fully integrate acoustically, and (unlike near-field measurements) includes the effects of front-panel reflections and cabinet diffraction.
The CD 250's directivity is quite uniform over its ±30-degree listening window, but the individual response deviations vary somewhat more than the averaged trace implies. Unusually, when the CD 250 is placed horizontally its response exhibits only minor lobing at angles wider than ±30 degrees, yielding sound with exceptionally good timbre-matching for off-axis listeners. The peaks at 10 and 16 kHz are evident in either orientation. The CD 220 surround speaker also has uniform directivity over a very wide arc and shares the CD 250's overall response characteristics, including its limited low-frequency capability.
I measured the AS 100 SC subwoofer's bass limits with it set to maximum bandwidth and placed in the optimal corner of a 7,500-cubic-foot room. In smaller rooms users can expect 2 to 3 Hz deeper extension and up to 3 dB greater sound-pressure level (SPL).
The subwoofer has usable output up to 180 Hz (where it measures -6 dB), because the first half octave of the low-pass crossover slope is only 6 dB per octave. The actual crossover turnover frequencies range from 46 to 117 Hz, wheras the dial markings run from 55 to 200 Hz. The crossover control also introduces a moderate 4-dB drop in overall level over its full operating range. When the room-compensation control is set to "narrow," response falls off by roughly 7 dB below 55 Hz and is increased by 2 dB at 70 Hz.
The AS 100 SC delivered a strong 106.5-dB SPL output at 62 Hz, but it fell to 92 dB at 50 Hz, and severe system distortion (buzzy rattles - most likely driver suspension noise) prevents the subwoofer from cleanly exceeding 80 dB SPL at 40 Hz or below.
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