OTHER TECH

TEST BENCH FOR WEB

SPEAKERS In the lab

Frequency response (at 2 meters) front left/right 86 Hz to 18.2 kHz ±5.8 dB center 86 Hz to 15.7 kHz ±4.9 dB surround 86 Hz to 16.4 kHz ±5.6 dB subwoofer 37 to 77 Hz ±2.3 dB Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) front left/right/center/surround 88 dB

Impedance (minimum/nominal) front left/right/center/surround 4.0/9 ohms

Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room) front left/right/center/surround 80 Hz at 83 dB subwoofer 32 Hz at 97 dB SPL 103 dB average SPL from 32 to 62 Hz 107.7 dB maximum SPL at 62 Hz bandwidth uniformity 95%

Satellites All 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 QS-SAT24R's response averaged over a ±30° window, with double weight at 30° (the most typical listening angle). The center-channel curve reflects a horizontally oriented QS-SAT24R's response averaged over ±45°, with double weight directly on-axis of the primary listener. The surround-channel curve shows the speaker's response averaged over ±60°. All measurements except for the subwoofer's are taken at a full 2 meters, which emulates a typical listening distance, allows the driver outputs to fully integrate acoustically, and - unlike near-field measurements - fully includes front panel reflections and cabinet diffraction effects.

When mounted vertically as a left/right or surround speaker, the QS-SAT24R has a 5- to 6-dB elevation between 1 and 6 kHz along with a curious notch centered at 2 kHz that appears at every listening angle. The ribbon tweeter's response peaks at 15 kHz and is quite directional, with response falling off rapidly (by some 17 dB above 10 kHz at ±45°) at increasingly wider listening angles. When mounted horizontally as a center channel, the satellite's output exhibits moderate lobing that actually improves response between 1 and 3 kHz at ±22° off-axis. More serious lobing develops at wider measurement angles, however, so listeners far off-axis may experience more colored sound.

Subwoofer The QS-SUB 100 subwoofer's bass limits were measured 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). The QS-SUB 100 has limited low- and upper-frequency extension, but dynamic capability is well-distributed for a small subwoofer. - Tom Nousaine

RECEIVER DOLBY DIGITAL PERFORMANCE All data was obtained from various test DVDs using 16-bit dithered test signals, which set limits on measured distorting and noise performance. Reference input level is -20 dBFS, and reference output is 1 watt into 8 ohms. Volume setting for reference level was 60. All level trims were set at zero, except for subwoofer-related tests, and all speakers were set to "large," subwoofer on. All values listed are worst-case figures where applicable.

Output at clipping (1 kHz into 8/4 ohms) 1 channel driven: 112/188 W 5 channels driven (8 ohms): 28 W* Distortion at 1 watt (THD+N, 1 kHz) 8/4 ohms: 0.1%/0.1% Noise level (A-wtd): -67.1 dB Excess noise (with sine tone) Not tested Frequency response: 20 Hz to 20 kHz +0, -0.9 dB

MULTICHANNEL PERFORMANCE, ANALOG INPUT Reference input and output level is 200 mV; volume setting for reference output level was 46 Distortion (THD+N, 1 kHz, 8 ohms): 0.04% Noise level (A-wtd): -77.2 dB Frequency response: <10 Hz to 73 kHz +0, -3 dB

STEREO PERFORMANCE, DIGITAL INPUT Reference level is -20 dBFS; all level trims at zero. Volume setting for reference level was 60. Output at clipping (1 kHz, 8/4 ohms, both channels driven): 94 W/85 W* Distortion at reference level: 0.09% Linearity error (at -90 dBFS): 0.3 dB Noise level (A-wtd): -70.8 dB with 96-kHz/24-bit signals: N.T. Excess noise (with/without sine tone) N.T. Noise modulation: N.T. Frequency response: 20 Hz to 20 kHz +0, -0.7 dB with 96-kHz/24-bit signals: N.T. *Current-limiting curtailed power in all-channels and 4-ohm stereo tests.

BASS-MANAGEMENT PERFORMANCE Measured results obtained with Dolby Digital test signals. Subwoofer-output frequency response (crossover set to 80 Hz): approx. 15 dB/octave rolloff above -6-dB point of 80 Hz High-pass-filter frequency response (crossover set to 80 Hz): 12 dB/octave rolloff below -3-dB point of 80 Hz Maximum unclipped signal level from subwoofer output (trim at 0): 6.5 volts Subwoofer output distortion (from 6-channel, 30-Hz, 0-dBFS signal; subwoofer trim set to 0): 3.0% Crossover consistency: bass crossover frequency and slope same for all signal formats that receive bass management; no bass management for multichannel or stereo analog inputs Signal-format consistency: consistent for all applicable formats; no bass management for analog signals Speaker size selection: all channels can be set to "small" (but not every combo of small/large is possible) Speaker-distance compensation: none

The QS-AVR500 A/V receiver included with the SLS Audio Q-Line Silver surround sound system exhibited typical response, distortion, and noise characteristics for a digital A/V receiver on the test bench, but predictably lacked significant power reserves. Although it measured 112 watts into 8 ohms with 1 channel driven (it would do more with the matched 6-ohm satellites), and delivered 94 watts x 2 in stereo, protection circuitry limited power output to 28 watts per channel with all five channels driven. - Daniel Kumin