Test Bench: Canton Vento Home Theater Speaker System
In the lab
Frequency response (at 2 meters) front left/right: 55 Hz to 20 kHz ±4.7 dB center: 81 Hz to 20 kHz ±3.7 dB surround: 82 Hz to 20 kHz ±3.2 dB subwoofer: 36 to 79 Hz ±2.3 dB
Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) front left/right: 91 dB center: 92 dB surround: 89 dB
Impedance (minimum/nominal) front left/right: 3.9/5 ohms center: 4.0/6 ohms surround: 3.9/6 ohms
Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room) front left/right: 32 Hz at 72 dB center: 50 Hz at 85 dB surround: 50 Hz at 78 dB subwoofer: 20 Hz at 86 dB SPL 105 dB average maximum SPL from 25 to 62 Hz 111 dB maximum SPL at 62 Hz
All of the curves in the frequency-response graph are weighted to reflect how sound arrives at a listener's ears with normal speaker placement. The curve for the left/right front channels reflects the Vento 809 DC's response with the speaker standing on the floor, averaged over a ±30° window. The center-channel curve reflects the 805 CM's response averaged over ±45°, with double weight directly on-axis of the primary listener. The surround-channel curve shows the 802's response averaged over ±60°. I measured the center and surround speakers's responses with them placed on a 6-foot stand, which gives anechoic results to approximately 200 Hz. Except for the subwoofer, all measurements are taken at a full 2 meters, which emulates a typical listening distance, allows the outputs of large speakers to fully integrate acoustically, and, unlike near-field measurements, fully includes front-panel reflections and cabinet diffraction.
The floorstanding Vento 809 DC has high sensitivity and an unusually flat impedance curve, along with well controlled directivity and relatively mild floor-bounce attenuation (less than 4 dB at 270 Hz). It exhibits a fair degree of irregularity in its frequency response above 500 Hz, and like the 805 CM center and the 802 bookshelf speakers used here as surrounds, it has a tweeter resonance at 20.5 kHz that makes numerical description of the data look better than an examination of the response trace reveals. The grille on my sample rattled noticeably during bass-limit testing at any frequency below 100 Hz.
The 805 CM center speaker's response begins lobing as soon as the microphone is moved off axis, and the effect gets progressively worse as the mike is moved further away from the sweet spot. The 802 direct-radiating bookshelf speaker used for surround duties has nicely controlled directivity, but there is also a fair degree of roughness above 1 kHz at every listening angle.
I measured the Vento AS 850 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 a smaller room users can expect 2 to 3 Hz deeper extension and as much as 3 dB greater sound-pressure level (SPL).
This subwoofer has good dynamic capability, delivering 86 dB SPL at 20 Hz and 104 dB or more at 32 Hz and above. Although the crossover dial is marked from 45 to 200 Hz, the sub's acoustical high-frequency cutoff varies only from 55 to 79 Hz over the full range of the control; this should not be a problem when mating the system with the large towers it's found with here but could be an issue in some installations with smaller satellites. There is only minor level interaction with the crossover control, except at the 45-Hz mark, where overall output falls by 17 dB compared to the level measured at the 200-Hz control position. The "wide" operating position increases output by 3.6 dB below 35 Hz while cutting response by 1.2 dB above that frequency. The "narrow" control setting cuts response by 7.6 dB below 60 Hz while adding 0.8 dB above 60 Hz.