BOTTOM LINE
While the Sony STR-DA4600ES’s GUI might not be my absolute favorite, don’t take away the idea that this formed my entire view of the receiver. It totally performed. This Sony never sounded less than excellent in either stereo or multichannel modes, and it offers impressive multiroom options and networking features. All this adds up to a mighty attractive package, one that certainly merits close consideration alongside the more “specialized” brands of competing A/V receivers.
DOLBY DIGITAL PERFORMANCE
All data were obtained from various test DVDs using 16-bit dithered test 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 -3. All level trims at zero; except for subwoofer-related tests, 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: 157/242 W (22.0/23.8 dBW)
5 channels driven (8 ohms): 65 W (18.1 dBW)
7 channels driven (8 ohms): ~20 W (13.0 dBW)*
*Restricted by protection circuitry when 6 or more channels driven
Distortion at 1 watt (THD+N, 1 kHz)
8/4 ohms: 0.03/0.04%
Noise level (A-wtd): -75.4 dB
Excess noise (with sine tone)
16-bit (EN16): 2.9 dB Frequency response: 20 Hz to 20 kHz +0, -0.2 dB
ANALOG INPUT PERFORMANCE (CDR/Tape Stereo In)
Reference input and output level is 200 mV; volume setting for reference output level was 0.
Distortion (THD+N, 1 kHz, 8 ohms): 0.03%
Noise level (A-wtd): -92.5
Frequency response: <10 Hz to 200 kHz +0, -0.7 dB
STEREO PERFORMANCE, DIGITAL INPUT
Reference level is -20 dBFS; all level trims at 0. Volume setting for reference level was 0.
Output at clipping (1 kHz, 8/4 ohms, both channels driven): 133/199 W (21.2/23.0 dBW)
Distortion at reference level: 0.03%
Linearity error (at -90 dBFS): -5.4 dB
Noise level (A-wtd): -75.2 dB with 96-kHz/24-bit signals: -77.2 dB
Excess noise (with/without sine tone) 16-bit (EN16): 3.1/0.8 dB quasi-20-bit (EN20): 18.6/18.7 dB
Noise modulation: 3.2 dB
Frequency response: Less than 10 Hz to 20 kHz +0, -0.3 dB with 96-kHz/24-bit signals: Less than10 Hz to 44 kHz +0, -3.1 dB
BASS-MANAGEMENT PERFORMANCE
Measured results obtained with Dolby Digital test signals.
Subwoofer-output frequency response (crossover set to 80 Hz): 12 dB/octave above -3-dB rolloff point of 80 Hz
High-pass-filter frequency response (crossover set to 80 Hz): 6 dB/octave below -3-dB rolloff point of 80 Hz
Maximum unclipped subwoofer output (trim at 0): 4.7v (see note)
Subwoofer distortion (from 6-channel, 30-Hz, 0-dBFS signal; subwoofer trim set to 0): 0.3% (see note)
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 front L/R = "small")
Speaker-distance compensation: available for all main channels.
The STR-DA4600ES's test bench performance was generally very good, but a few comments are in order. Power into one and two channels was very generous, and while the receiver still managed 65 watts simultaneously into five 8-ohm loads (which I consider quite good), adding more channels induced its power-supply-protection circuits to limit available current, restricting output into 6 or 7 channels (for more than a small fraction of a second) to about 20 watts. I do not consider this an important point, as real-world program material will, essentially, never make this kind of in-phase, many-channel power demand.
Distortion and noise performance were similarly excellent, with one caveat: The DA4600ES appeared to have a small-bit error in its digital-to-analog conversion, or possibly digital filtering, which showed a fairly significant nonlinearity (5.4 dB) when decoding a -90 dBFS signal — the first such error I've encountered in many months. Linearity at -80 dBFS and above was essentially perfect, so the audible impact of this phenomenon is highly debatable. I was just able to hear the resultant noise-modulation error — but only on headphones at unrealistically high volumes using our custom-tooled fade-to-noise dithered tones. In short, I never heard any hint of it during in-room speaker listening, and rather doubt that anyone ever will. A bit surprisingly, this did not appear to affect 16-bit PCM S/N, which was almost spot-on, but 24-bit PCM S/N only improved a paltry couple of decibels. The receiver's outstanding analog multichannel-input S/N tells me that whatever was going on here was going on in the digital domain.
Finally, as with several other Sony receivers I've examined, the DA4600ES's speaker crossover filters use 12-dB/octave low-pass and 6-dB high-pass rather than the de facto standard 18/12-dB/octave. Most speaker/subwoofer combos will tolerate this without much audible impact, but others may require some careful listening and subsequent placement and level tweaking to yield the best, "tightest" integration — always the best practice in any event.-D.K.
