The New Surround Formats – what.what.what??
And now for something completely different (but first a little history)…
Once upon a time, long, long ago, music listening at home started with mono. Then stereo came along adding to the illusion of a performance on stage. For a brief moment Quad (4-channel) took us on a side trip. Dolby employed under license one “matrixed” (matrixed = two channels blended into the existing stereo L/R channels and retrieved upon playback) version of Quad (Sansui’s QS) in theaters. They named it “Dolby Stereo” and the 4 channels were left front, right front, center channel and a single frequency limited surround channel using multiple speakers spread around the back and side walls of commercial theaters.
Dolby Stereo came to home theaters renamed as Dolby Surround, but, among other features, it didn’t include the logic steering used in theaters to reduce the inherent bleed of signals between channels. Logic steering is an automatic volume control working on all 4 channels to reduce output when there isn’t supposed to be sound there. Eventually logic steering was added to home theater electronics and Dolby Stereo was renamed Dolby ProLogic. Next came Dolby AC-3, also known as Dolby Digital, with between 1 and 5 discrete full range digital channels plus a subwoofer channel for Low Frequency Effects (LFE) and bass management. The vast majority of films produced since have been created using some variation of the “5.1” system with three front channels, two surround channels (the “5”) and the “.1” subwoofer channel.
Over time Dolby Digital eventually came to include an additional matrixed surround channel used for 6.1 systems and this version was called Dolby Digital Surround EX. More recently front height and/or width channels were added too. While all this was going on, DTS developed and introduced their competing surround formats with similar configurations and many surround films and concerts include both Dolby and DTS soundtracks. All of these systems were channel based with sounds emanating from one or more speakers determined by where these speakers were physically positioned in the room. FYI, we have skipped over a few other side trips to other Dolby and DTS multi-channel software versions (ProLogic 2, DTS Neo, etc.). All these systems were based upon the physical location of the speakers to determine where sounds appeared to come from.
Truly new and different
Recently something dramatically new and different has been introduced to the surround world; object based surround sound. Dolby has introduced Dolby Atmos and DTS has introduced DTS:X. Several other companies have introduced variations on these concepts too. The dominant Dolby and DTS systems utilize a new object based surround concept that allows sound mixers to place any individual or group of sounds at any chosen location throughout the room, unfettered by physical speaker location. There are additional channels that allow them to do this.
The Atmos system includes a process called “adaptive rendering” which combines the added sound channels with object based steering. If there is a speaker located where the sound is supposed to come from, the rendering engine sends the sound to it. If there isn’t a speaker located there, the engine determines what steering process it has to use and which speaker(s) have to be employed to make the sound appear to come from where it’s supposed to. It appears that DTS:X does a similar feat of magic. Ah, ain’t computers grand?
Now engineers can place an audio object anywhere in the room, including above the listening area, with precision impossible in conventional multi-channel mixes. This results in what’s effectively a dome of sound sources throughout the space, creating a much more natural and immersive sound field.
What’s required to recreate the sound field at home is a processor that can decode or simulate these soundtracks and at least 2 additional speakers located above the listening space (we will ignore the less desirable “speakers on top of fronts and surrounds aimed up to reflect off the ceiling” alternative, here we are talking about the real deal!). Atmos and DTS:X enabled receivers are already on the market while some current models are updateable through software. It’s an easy assumption that almost all newer surround electronics will include this capability, and very soon all new movies and all the big TV series will be Atmos-encoded. These new formats are described based on the number of ear-level channels and height channels employed, so a “5.1.4” means 5 main speakers, 4 height speakers, and 1 subwoofer channel. That system would then require a 9-channel, Atmos-ready receiver. Atmos configurations for the home can go all the way up to 24.1.10 (no kidding), but its a pretty safe bet that most home systems will be somewhere between 5.1.2 and 7.1.4.
So, all you’d need to add to a typical 5.1 existing system, in terms of speakers, is one or two pairs of in-ceiling models positioned over the listening area. Our experience so far has indicated that 4 ceiling mounted speakers which closely match the other speakers in the system in terms of sonic signature, are by far the best solution. Models like our Invisa HTR 7000 are perfect for this kind of system in typical home theater rooms with 8 foot ceilings (and can actually be used for every position in the system, not just the height speakers). If the ceiling is higher than 10 feet, our Invisa 650 makes a great height channel speaker in a full GoldenEar home theater.
What you’ll experience with a good, properly set up Atmos or DTS:X system is an order of magnitude beyond anything you’ve heard with surround systems until now. There’s just no comparison between what’s come before and these latest formats. They can truly immerse you within a believable sound field making for a much more realistic experience. Although, we have to caution that Atmos by itself does not make a mediocre system great, butt it surely makes a great surround system like one based on GoldenEar speakers that much more wonderful. We strongly urge you to stop by your local GoldenEar dealer for a demo. You’ll be glad you did. Want some more information? Click Here to check out the Atmos Systems section on our website.
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