Setup: Fast and (mostly) accurate
Just like every other Pioneer receiver we've tested, the VSX-823-K features the company's proprietary MCACC (Multi Channel Acoustic Calibration) automatic speaker calibration system. Unlike the Audyssey system featured in Onkyo and Denon receivers that asks the user to move the mic to multiple room positions, MCACC gets the job done with one position, taking just 2 minutes to complete, while offering results that are just as accurate.
Which is to say, no automatic calibration setup program is 100 percent accurate. MCACC identified the size of our Aperion Intimus 4T towers as "large" speakers. They are towers, but their dual 4-inch woofers don't generate the deepest bass frequencies. In any case the VSX-823's sound quality was excellent, so we didn't feel a need to change any of the settings.
This Pioneer's bass management options are more limited than some receivers': it applies the same subwoofer-to-speaker crossover frequency to all "small" speakers, and in this case that frequency was 100Hz for the center and surround speakers. Denon's Audyssey bass management is more flexible and can assign different crossover frequencies to the front-, center-, and surround-channel speakers to compensate for various sizes of speakers and their bass capabilities. While that might make a difference in theory, the VSX-823's speaker-subwoofer blend wasn't an issue, and the sound quality was very good.
Sound quality: Powerful, clear sound
Sound-quality evaluations of AV receivers (and other amplifiers) are controversial. Some say all AV receivers sound the same, others disagree, and we're not likely to settle that argument anytime soon.
What we can say is that AV receiver sound quality has much, much less effect on overall sound quality than speakers or room acoustics, so you're better off spending your home theater budget there. CNET's sound quality evaluations are strictly subjective, with resident golden ear Steve Guttenberg comparing similarly priced models in an identical listening environment using the same speakers.
The VSX-823-K sounded remarkably well-balanced with all of the movies and music we played. The front and surround speakers together created a coherent sound field in the CNET listening room. Soundstage depth was good, so the sound would, depending on the mix, appear behind the plane of the speakers. Home theater muscle was impressive, so the wide-ranging power dynamics required by the rampaging Hammerhead Titanotheres in "Avatar" packed a wallop.
While listening to jazz singer Patricia Barber's superb "Modern Cool" high-resolution audio Blu-ray we heard more texture and growl from the acoustic bass strings than we did with the Denon AVR-E400. The clarity of the percussion instruments was also better on the VSX-823-K. The differences weren't huge, but the Denon's richer but less detailed sound signature was apparent. We also felt the VSX-823-K sounded better when played really loud.
The VSX-823-K's Midnight Mode compression didn't have much effect when we switched it on and off; abrupt soft-to-loud volume changes were still there. Audyssey's Dynamic Volume processing on the Denon AVR-E400 did a better job of maintaining a consistent volume level for late-night listening sessions. Two-channel music on CD sounded big and spacious coming from just the Aperion 4T tower speakers and the Hsu Research VTF-1 subwoofer.
What are the alternatives?
The strongest alternative to the VSX-823-K is the Sony STR-DN840. It packs the same six HDMI inputs, plus it adds lots of wireless functionality, including built-in Wi-Fi, Bluetooth, and AirPlay. That's worth the extra $50 to us, especially with Pioneer's own wireless accessories costing so much.
The Marantz NR1403 is also worth considering at this price. It eschews networking features entirely, but it looks better and still sports six HDMI inputs. Plus, you can always add on the networking functionality you want later with, say, an Apple TV, which is arguably the smarter move.
Finally, it's worth considering whether you even need an full-fledged AV receiver in the first place. If you're willing to downsize your home audio system to stereo, you might be able to use a compact integrated amplifier. They sound great, take up a lot less room, and can make your home theater much simpler.
Conclusion: For AirPlay fans that don't need Wi-Fi
The VSX-823-K isn't our first choice for a midrange AV receiver, but it does stand out by offering more HDMI connectivity and AirPlay than other receivers at this price.