Top Ad unit 728 × 90

Dolby Atmos at home: Does bouncing sound off a ceiling really work?

Mark Walton
For nearly 30 years, the humble home surround-sound setup hasn't changed much. Sure, we've gone from having centre and rear channels matrix-encoded into ordinary stereo tracks via Dolby Pro Logic, through to the clarity of discrete 5.1 channel mixes with Dolby Digital, but the physical speaker setup remains the same: three at the front, two at the back, and a subwoofer for bass. So common is this setup—nearly every all-in-one surround system on sale is 5.1—not even the lure of lossless 24-bit/96kHz audio and the added immersion of two extra surround channels has convinced the average Joe to add more speakers.
Which leaves the Atmos, Dolby's latest and greatest audio format, in something of a predicament. The system, which debuted alongside Pixar's Brave in cinemas back in 2012 and is now available at home on Blu-ray, is probably the most immersive surround-sound experience currently available. Cinemas are able to install as many as 64 speakers to move the sound not just around listeners, but above them as well. As someone who's had the fortune of watching a few films inside Dolby's London-based screening room—which also sports a laser-based projection system for higher dynamic range—as well as taken to the decks in the Atmos-equipped Ministry of Sound, I've experienced first-hand that Atmos can sound spectacular. But there's also no way I would install speakers in my ceiling to recreate the experience at home.
Fortunately, there are ways of making Atmos practical, from speakers with upward-firing drivers like KEF's R50, to all-in-one soundbars like the Samsung HW-K950. And while a 4K HDR TV is great—read our full guide on 4K HDR if you're yet to invest—it's only half of the experience. Even if Atmos in the home is no substitute for a cinema, the results, particularly in the case of the Samsung soundbar, can be very impressive indeed.

Objects, not channels

Dolby Atmos differs from its predecessors in that it's object-based, not channel-based. In a standard 5.1 Dolby Digital surround mix, individual sounds are assigned to a specific channel. So, if a filmmaker wants the sound of a car to come from behind the listener on the left, the sound must be assigned to rear left surround channel. If a filmmaker wants a musical score to burst through all speakers at once, it has to be assigned to every channel. This setup works fine, but what if the listener doesn't have a 5.1 surround setup (traditionally solved by including a separate stereo mix), or what if there are more speakers?
The interface used to mix a Dolby Atmos film. The yellow dots in the lower right represent sound objects that can be moved around the listening space.
Enlarge / The interface used to mix a Dolby Atmos film. The yellow dots in the lower right represent sound objects that can be moved around the listening space.
With Atmos, instead of a sound being assigned to a specific channel, it's assigned to an XYZ coordinate inside a virtual 3D space. The sound can then be dragged around that space any which way a filmmaker chooses, with a compatible Atmos system taking that data and distributing it across the number of speakers used. Atmos supports anything from two speakers (although, that's essentially just backwards compatibility for stereo) all the way up to 64. In theory, then, even those running a standard 5.1 speaker setup stand to benefit in a small way from Atmos sound. To get the most out of Atmos, though, there needs to be speakers positioned above the listener.
Since speakers installed in or on the ceiling just aren't practical for most—even adding those extra two for 7.1 surround isn't an option for many—most speaker and amp-makers are taking advantage of Atmos' object-based nature to simulate ceiling-based speakers by reflecting the sound. Upward-firing drivers positioned on the front or rear speakers can, in theory, bounce the sound off the ceiling of your living room, giving the impression that sounds are coming from above you—and all without adding to the footprint of a 5.1 speaker setup. There are even sound bars with upward-firing drivers, allowing for a single-speaker solution, albeit a somewhat compromised one, to the problem.

When is Atmos "Atmos"?

Most mainstream AV receivers that support Dolby Atmos are seven-channel amps. That means, in addition to the standard front-left, front-right, centre, rear-left, rear-right, and subwoofer channels, there are an additional two that can be used for ceiling speakers or upward-firing drivers. This 5.1.2 setup is featured on numerous receivers from the likes of Sony, Denon, and Onkyo, to name but a few, as indicated by the helpful Atmos logo on the box or the front panel. Some older receivers without Atmos support can receive a firmware update to enable it, too, but for the most part you'll need to upgrade.
Those with deeper pockets and larger living spaces can opt for a nine-channel amplifier, or even one with 11 channels, which can use up to four ceiling-mounted speakers or upward-firing drivers alongside an additional two speakers positioned directly to the left and right of the listener for a for a 5.1.4 or 7.1.4 setup. It's possible to go ever further with specialised setups, but given the amount of money they cost, it's likely there'll be an expert installer included in the price.
This picture shows a full 7.1.4 Dolby Atmos setup with four sets of upward firing drivers.
Enlarge / This picture shows a full 7.1.4 Dolby Atmos setup with four sets of upward firing drivers.
The alternative to an invasive and expensive multi-speaker setup is the soundbar. Yamaha is mostly credited with turning the soundbar from something that only the most space-deprived listeners purchased into a genuinely impressive home cinema experience thanks to its sound-beaming technology, which emulates surround sound by bouncing the sound around a room using an array of highly-focused drivers. While there are still plenty of duff soundbars around, which offer little more than increased volume over a TV's built-in speakers, the likes of Sonos, Philips, Sony, and LG, to name but a few, have been churning out quality devices. Even old-school speaker-makers like Dali and Q Acoustics have got in on the action.
Only a handful support Atmos, however, and of those only two currently offer a convincing-enough surround sound package (at least until Philips releases its take). These are the Yamaha YSP-5600, and the Samsung HW-K950. Both are expensive, with the Yamaha costing just shy of £1,500/$1,600, and the Samsung selling for £1,300/$1,500. However, it's worth bearing in mind that a separates setup, while more flexible in the long run, can easily cost hundreds, if not thousands more than that, depending on the components chosen. That's not to mention all the cabling required, and the space needed for the speakers.
Well, sort of. The Yamaha YSP-5600 uses a single, impractically tall soundbar for its surround sound, which most reviewers noted is far too big to actually sit underneath most TVs. The Samsung HW-K950, however, includes not only a separate subwoofer, but also two medium-sized surround speakers with upward-firing drivers. Fortunately, all are wireless bar a power cable, which makes installation and general life-partner approval that much smoother. And the effort of placing them is worth it: the Samsung HW-K950 sounds like no other soundbar I've heard.
Dolby Atmos at home: Does bouncing sound off a ceiling really work? Reviewed by Chidinma C Amadi on 3:22 PM Rating: 5

No comments:

Kogonuso © All Rights Reserved!

Contact Form

Name

Email *

Message *

Powered by Blogger.