OTHER TECH

COMPLETE TEST BENCH

VIDEO PERFORMANCE Color temperature (Ideal color temperature and contrast before calibration/User color temperature and Ideal contrast after calibration) Low window (30-IRE): 7,534/6,477 K High window (80-IRE): 7,385/6,556 K Brightness (100-IRE window before/after calibration): 51.4/48.5 ftL

The JBL plasma's Ideal color-temperature preset measured reasonably close to the 6,500-K target, but it benefited from grayscale calibration via its User controls. Color rendition improved after adjustment, with grayscale linearity varying within ±300 K - an average level of performance. (Calibration needs to be performed by a qualified technician, so discuss it with your dealer before purchase, or call the Imaging Science Foundation at 561-997-9073.)

The set's Ideal picture-contrast setting delivered the most linear gamma, a measurement of how evenly image brightness increases as the picture shifts from black to white. A 720p resolution test pattern showed clean single-pixel gradations, indicating that the set could display HDTV programs in that format with full detail. Color decoding was poor when the set's built-in DVD changer was used, measuring -25% red and -15% green on the Avia Pro test DVD's color-decoding error pattern. This problem was alleviated somewhat by increasing the color control and afterwards wasn't particularly noticeable on the movies I watched. Picture overscan was a higher-than-average 5% with both the TV's component video and DVI inputs selected. -Al Griffin

DOLBY DIGITAL PERFORMANCE All data were obtained from test DVDs using 16-bit test signals containing dither, which sets limits on measured distortion and noise performance. Reference input level is -20 dBFS, and reference output is 1 watt into 8 ohms. Volume setting for reference level was -1. All level trims were at 0 except for subwoofer-related tests, all speakers set to "large," subwoofer on. All are worst-case figures where applicable. Output at clipping (1 kHz into 8) 1 channel driven: 73 W (18.5 dBW) 2 channels driven: 73 W (18.5 dBW) 5 channels driven: 71 W (18.5 dBW, see notes) 7 channels driven: see notes Distortion at 1 watt (THD+N, 1 kHz) 8 ohms: 0.07% Noise level (A-wtd): -71.5 dB Excess noise (with sine tone) 16-bit (EN16): +3.5 dB Frequency response: 20 Hz to 20 kHz +0.15, -0.23 dB

DVD-AUDIO PERFORMANCE All signals were 24-bit, 96-kHz sampling rate. Reference level is -20 dBFS; all level trims were at 0. Volume setting for reference level was -5. Distortion at reference level: 0.06% Noise level (A-wtd): -76.2 dB Noise modulation: <0.5 dB Frequency response: 20 Hz to 43.6 kHz +0.1, -3 dB

STEREO PERFORMANCE, CD AND DIGITAL INPUT All signals were PCM and 16-bit except where noted otherwise. Reference level is -20 dBFS; all level trims were at 0. Volume setting for reference level was -5. Distortion at reference level: 0.07% Noise level (A-wtd): -71.1 dB Noise modulation: <0.5 dB Frequency response: 20 Hz to 20 kHz +0.2, -0.15 dB

BASS-MANAGEMENT PERFORMANCE Measured results obtained with Dolby Digital test signals. Subwoofer-output frequency response (crossover set to 90 Hz): 12 dB/octave rolloff above -3-dB point of 90 Hz High-pass-filter frequency response (crossover set to 80 Hz): 12 dB/octave rolloff below -3-dB point of 90 Hz Maximum unclipped subwoofer output (subwoofer trim at -6): 4.2 volts Subwoofer distortion (from 6-channel, 30-Hz, 0-dBFS signal; subwoofer trim set to -6): 0.79% Crossover consistency: bass crossover frequency and slope same for all signal formats Signal-format consistency: consistent for all applicable formats Speaker-size selection: all channels can be set to "small" Speaker-distance compensation: available for all main channels

The basic audio performance of the CinemaVision system was good, but a few numbers require comment. While it didn't deliver its rated 100 watts per channel, the maximum levels it did manage to reach were only 1.5 dB less than that. The protection circuitry shut the receiver down during our most stressful power tests. In the case of the five-channel test the shutdown occurred right at the clipping point. During the extremely tough seven-channel test the receiver turned off at around 60 watts per channel, before clipping had been reached. But even if you use the slightly elevated volume settings of our tests, it's unlikely that normal program material will stress the receiver this much. In any event, pumping even 60 watts per channel into seven speakers should deliver extremely loud volume in a typical listening room.

As we've been finding too often lately, this receiver's noise levels were slightly elevated in CD playback, though not so much as to be a major concern. However, the noise didn't lessen substantially during our DVD-Audio tests, which means that playback in this format will have a practical dynamic range approximately equal only to that of 16-bit CD playback.

To completely avoid overloading the subwoofer output, you should turn down the subwoofer level-trim control to -6 or lower and compensate, if necessary, by raising the subwoofer's own volume control. Also, to be certain that bass-management processing is correctly applied to all signal formats and inputs, you should adjust it for "global" operation as specified in the setup procedure. -David Ranada

SPEAKER PERFORMANCE Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) front left/right/center/surround: 92 dB Impedance (minimum/nominal) front left/right/center/surround: 5.0/6 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 89 dB surround: 80 Hz at 84 dB subwoofer: 25 Hz at 88 dB SPL 104 dB average SPL from 25 to 62 Hz 111 dB maximum SPL at 62 Hz bandwidth uniformity 93%

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 response of the CVSAT50 L/R satellite averaged over a ±30° window, with double weight at 30° (the most typical listening angle). The center-channel curve reflects response of a horizontally arrayed CVCEN50 center speaker averaged over ±45°, with double weight directly on-axis of the primary listener. The surround-channel curve shows the response of the CVSAT50 averaged over ±60°.

The CVSAT50 had very uniform directivity. There was a 6-dB "bump" from 500 Hz to 2 kHz measured directly on-axis, but it flattened out at wider listening angles. Users should avoid angling these speakers inward when they're in the front left/right positions. A high-frequency roughness is visible in all traces. The CVCEN59 is merely a CVSAT50 resting on its side and had the same overall characteristic as the CVSAT50 measured directly on-axis, but significant off-axis lobing began at ±15° and got progressively worse at wider angles.

The CVSUB50 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 up to 3 dB higher sound-pressure level (SPL). Crossover functions for the subwoofer are performed in the receiver. The subwoofer has no operating controls other than level and phase, so there was no cross-control interaction. Response was quite powerful at 62 Hz, but dynamic capability fell at 14 dB per octave below that frequency. -Tom Nousaine