From the AVS Forum archives (posted June 2017)…
Dolby Atmos is understandably popular with the home theater crowd, thanks to the height effects 3D immersive audio provide. From flyovers to raindrops on a roof, having sounds come from above is more realistic than traditional two-dimensional surround-sound. And thanks to Atmos-enabled speakers, you don’t need to cut holes in your ceiling or run cables in your walls to enjoy the benefits.
While some movies feature Atmos soundtracks, it is also possible to upmix. That’s because Atmos has a feature called Dolby Surround that processes music and movies using ambience extraction, which takes advantage of the height speakers.
I’ve been upmixing stereo music tracks with Dolby Surround ever since I first added Atmos to my home theater system two and a half years ago. I love the ambience it adds to the experience, but so far I’ve always upmixed stereo tunes to either a 5.1.4 or a 7.1.4 speaker system.
Typically, when Dolby Atmos discussions get started, the topic turns toward adding more speakers to a system, for a more complete sense of immersion. But, as 2-channel enthusiasts know, well-reproduced stereo tracks also create an immersive soundfield. And if you put your entire speaker budget into two speakers, instead of five or seven speakers, you can get a pair that offer better performance when pressed to perform two-channel duty.
There are lifestyle concerns that also make a 2-channel system attractive. Two speakers in a living room, flanking a TV, are likely to be an easier sell than seven speakers, or more if you put height speakers on the walls or in the ceiling. You could wind up with 11 separate speakers, and while that’s cool in a basement or a dedicated media/home theater room, it probably won’t fly in a living room or TV room. But a pair of speakers and maybe a sub? That has potential.
With all that in mind, I wondered what would happen if I combined two-channel listening with Atmos. Once that notion took hold, my first instinct was to search Google to see what’s been posted on the topic in the past. Certainly the ability to set up a 2.1.2 system (2.2.2 counting the use of dual subs) did not go unnoticed, but I could not find a speaker review that featured such a configuration.
First of all, why use Atmos for 2-channel listening? And in particular why use Atmos-enabled speakers? Because every place you’ve heard live music, the sound that reflected off the ceiling played a huge role in what you actually heard. From jazz clubs to concert halls to opera houses to cathedrals, ceiling height and room size are key ingredients when it comes to the ambience of a recording.
Traditional surround-sound could simulate a large space, but not a high ceiling. The difference height-related ambience makes for music playback with Dolby Surround ranges from mild but pleasing to profound. And crucially, it never detracted from the listening experience.
Using sophisticated software algorithms, Dolby Surround isolates the ambient elements of a recording and recreates them with lifelike realism. And here’s the cool part: the reflected-sound speakers are even better at rendering this effect than on-wall or in-ceiling speakers.
Now, I understand it’s perhaps a bit heretical to suggest that Atmos constitutes an upgrade for 2-channel listening. But unlike silly stuff like cable risers and python-thick power cords, Atmos does something that directly relates to real-world listening. Plus, if you don’t like what Dolby Surround is doing, you can turn it off with the press of a button—no loss.
A good hypothesis is one thing, but what I’m interested in is tangible results. Since we’re talking 2-channel audio, I wanted to put together a 2.2.2 speaker outfit using high-quality gear. I sought a solution that solidly bridges the gap between multi-channel AV systems and high-performance stereo systems, so I settled on KEF’s R500 tower speakers ($2599/pair), R400b subs ($1699) and R50 Atmos-enabled modules ($1199/pair). Yes, that’s a $7196 2-channel Atmos-enabled speaker system, if you are counting. And it sounded amazing.
The KEF gear comes with a premium price but offers the advantage of using the same Uni-Q concentric driver for both the tower and the Atmos module. The benefit is it acts as a point-source and is timbre-matched, a combo that results in a more cohesive and detailed soundstage. Last year I reviewed a 5.2.4 system containing the R500s and R50s, so I knew they were good performers and the right choice for this experiment.
The AVR running the show was more affordable. I used a Denon X4300H AVR ($1499) for processing and amplification—including Audyssey room correction. Because the power supply was not spread thin powering nine channels, the AVR delivered ample wattage to the towers and Atmos-enabled modules—especially with dual subs handling deep bass.
I spent a month with the KEF R-series 2.2.2 system and quickly forgot that it was not a surround-sound system. While I can’t prove anything with measurements or double-blind tests, the added ambience achieved by Atmos even made video games sound better. And movies. The uncanny effect of Dolby Surround upmixing was to create the illusion of listening to larger, taller speakers. The overall awesome sound was accentuated by the tight, deep bass from the twin R400b subs. From Daft Punk to Schoolboy Q to Art of Noise and dozens of other artists I love, the effect of this system was to raise the bar on what I expect from 2-channel sound.
Of course, when listening to Atmos-encoded soundtracks, the discrete height effects are present in the 2.2.2 system. This can add quite a bit to the viewing experience. It’s not quite the boost in immersiveness that going from 2 to 5.1 channels provides, but it counts as a sizeable leap forward nonetheless.
Because most folks are not ready to drop $11,292 on a 2-channel rig, I configured a second Atmos-enabled outfit using a Marantz SR7010 AVR ($1100 refurbished) paired with two Klipsch RP280FA Atmos-enabled tower speakers ($799/ea) and twin R-115SW subs ($899/ea). Here, the total cost of speakers is $3396, which is still a lot but considering what you get, actually quite a bargain. This particular configuration is part of a larger Klipsch 7.2.4 system I use as a home theater reference (along with the KEF rig, I swap between them) so I only had to reprogram the AVR’s speaker setup settings to make it work. This rig’s energetic output is “off the hook” when it comes to clarity and dynamics.
Klipsch may not have the refinement, build quality, or aesthetics of KEF gear—and the system is much larger—but the big towers have high sensitivity and belt out amazingly dynamic tunes. The Klipsch rig aced all the heavy-hitting rap and dubstep tracks I threw at it, with the added benefit of the expanded soundstage.
The main thing I learned in this process is that, to my ears, pure 2-channel sound was never as good as 2-channel sound with Atmos-enabled speakers and Dolby Surround ambience extraction. Each end every time I compared the two, the improved sense of space the height and ambience was there.
If you already have an Atmos-enabled surround-sound system, you can try out 2.0.2, 2.1.1, or 2.2.2 listening by altering your AVR or pre/pro’s speaker setup. And if you do check it, don’t be afraid to play with the levels of the elevation channels. When upmixing music, you can fine-tune the amount of ambience extraction that way. You might discover you really like what it does for music, I know I did.
One more thing: I don’t plan to stop listening to music this way. I wrote this post to start a discussion on what appears to be an underrated, underappreciated way to improve the 2-channel listening experience. While I used somewhat pricey high-performance gear, I am confident it has benefits for more modest systems. So, if you do try it, let me know what you think in the comments.