I encountered no glitches or surprises while testing the Sunfire Theater Grand Receiver 3. Power output was consistently among the highest I have measured from a multichannel receiver, and its 165 watts (22.2 dBW) per channel with 5 channels driven represents a clear benchmark for the category (3 to 4 dB greater than flagship receivers from many other manufacturers achieve). The Sunfire could run several dB into full clipping without shutting down or complaining, though it got distinctly warmer under those circumstances.
Noise was generally very low - a half to 1 dB shy of the theoretical ideal on our real-world dithered-signal tests through the digital inputs. Noise through the multichannel analog inputs was a few dB greater than in the best receivers we've tested, however, possibly a consequence of byproducts from the Sunfire's unconventional amplifier. But since we're still dealing with an effective dynamic range of greater than 100 dB from well-recorded hi-rez audio sources, this is of little consequence.
DOLBY DIGITAL PERFORMANCE
All data were obtained from various test DVDs using 16-bit dithered signals, which set 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 76.5. All level trims were set to zero, except for subwoofer-related tests, and all speakers were set to "large," subwoofer on. All are worst-case figures where applicable.
Output at clipping (1 kHz into 8/4 ohms)
1 channel driven: 252/377 watts (24.0/25.8 dBW)
5 channels driven (8 ohms): 165 watts (22.2 dBW)
6 channels driven (8 ohms): 161 watts (22.1 dBW)
Distortion at 1 watt (THD+N, 1 kHz)
8/4 ohms: 0.03/0.04%
Noise level (A-weighted): -74.3 dB
Excess noise (with sine tone)
16-bit (EN16): 0.7 dB
Frequency response: 20 Hz to 20 kHz +0.1, -0.5 dB
MULTICHANNEL PERFORMANCE, ANALOG INPUT
Reference input and output level is 200 mV; volume setting for reference output level was 76.0.
Distortion (THD+N, 1 kHz, 8 ohms): 0.02%
Noise level (A-weighted.): -82.7 dB
Frequency response: <10 Hz to 66 kHz +0.5, -3 dB
STEREO PERFORMANCE, DIGITAL INPUT
Reference level is -20 dBFS; all level trims at zero. Volume setting for reference level was -1.0 dB.
Output at clipping (1 kHz, 8/4 ohms, both channels driven): 238/345 watts (23.8/25.4 dBW)
Distortion at reference level: 0.02%
Linearity error (at -90 dBFS): 0.4 dB
Noise level (A-weighted): -74.8 dB
with 96-kHz/24-bit signals: -81.6 dB
Excess noise (with/without sine tone)
16-bit (EN16): 0.8/0.5 dB
quasi-20-bit (EN20): 13.0/13.0 dB
Noise modulation: 0.4 dB
Frequency response: 20 Hz to 20 kHz +0.5, -0.5 dB
with 96-kHz/24-bit signals: 20 Hz to 42.5 kHz +0.1, -3 dB
Measured results obtained with Dolby Digital test signals.
Subwoofer-output frequency response (crossover set to 80 Hz): 24 dB/octave above -6-dB rolloff point of 81 Hz
High-pass-filter frequency response (crossover set to 80 Hz): 12 dB/octave below -3-dB rolloff point of 79 Hz
Maximum unclipped subwoofer output (trim at 0): 8.6 volts
Subwoofer output distortion (from 6-channel, 30-Hz, 0-dBFS signal; subwoofer trim set to 0): 0.03%
Crossover consistency: bass crossover frequency and slope were consistent for all sources and formats
Signal-format consistency: consistent for all applicable formats
Speaker size selection: all channels can be set to "small" (if C=small, LR also must be "small")
Speaker-distance compensation: available for all main channels
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