# Dolby Atmos at home - the technological hurdle is tiny



## keithlock

Does the idea of Dolby Atmos at home sound appealing? It is technology that may come to the home theater sooner rather than later.

Launched about a year ago in the digital cinema arena, is the scalable surround-sound format by Dolby that has so far made its way into over 30 theatrical releases, with implementation in over 90 theaters spanning 28 countries, after being adopted by 7 major Hollywood studios.








As of right now, the technology used in the digital cinema delivers "sound objects" (i.e. individual sounds) to as many as 64 speakers (which include speakers above the crowd), covering only half of its current capability of 128 simultaneous sounds.

To illustrate the major difference between current surround technologies and Atmos, we could look at how the sounds are "described." In traditional formats, sound mixers, in a five-channel system, may assign several sounds to just one channel, which can muffle any of the "realism" of the resulting sound. In contrast, Atmos sounds will be described in 3-dimensions by attaching X, Y, and Z coordinates to define the sound's location, creating a much more realistic sound as a result.

Therefore, with Atmos, the sounds are more life-like and are heard more distinctly and clearly. This effect cannot be accomplished with the limitations of jamming multiple sounds into a limited number of channels.

Atmos surround sound pans very smoothly, and regardless of where the viewer/listener is seated, the surround experience is improved.

The scalability of the format allows Atmos playback into theaters (cinemas and at home) with even less than 64 speakers. Allegedly, "Atmos could be embedded in an active soundbar to deliver surround-sound performance that exceeds that of current soundbars with various types of virtual-surround processing," according to an unnamed source in the article at Twice.com.

Independent of room size and the acoustic characteristics of the room, Atmos can be calibrated to work in an optimal way.

The soundtrack for the movie, naturally, is coded specific for the Atmos experience. In terms of home theater availability, the soundtrack would work on current Blu-ray technology (discs and players). Existing cables (HDMI) can handle the encoding, so all that would be lacking is the decoding on the receiver's end.

In terms of A/V receivers with Atmos decoding capabilities, the jury is still out on when those may be delivered. "No one is saying when those A/V receivers will be available, but there doesn't seem to be any technical limitations that would prevent those receivers from becoming available sooner rather than later."

Manufacturers of the receivers might not make decisions on this matter until a final word comes from the Blu-ray Disc Association (BDA) in regards to new technologies that make it into the new Blu-ray specs. Considerations might include: 4K technology, expanded color space, frame rates, and audio codecs.

Perhaps the decoding can take place on the "Blu-disc level" leaving no need for a receiver with such a capability?

In terms of timing for the next-gen Blu-ray specification, a BDA spokesman said, "It's very difficult to say exactly (or even roughly) when something tangible will come out of the process, but I think everyone involved is motivated to keep things moving as efficiently as possible."

Image Credit:
digitaltrends.com


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## B- one

Small problem I can see if it happens WAF. Hey honey we need more speakers. Now I'm grounded again.


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## Kal Rubinson

keithlock said:


> Perhaps the decoding can take place on the "Blu-disc level" leaving no need for a receiver with such a capability?


Yadda, yadda, yadda. 

But how can the decoding take place on the "Blu-disc level?" It is not a processing or, even, a read/write device and cannot respond to the local speaker arrangements and that is essential to the process.


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## NBPk402

Why couldn't a person take a set of Bose 901 speakers and take all the speakers out and put them in little boxes... I am not a Bose fan but I am thinking full range speakers might be the route to go for a Atmos Home Theater on a budget. Not to mention you could flush mount the boxes in the ceiling and walls.


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## cavchameleon

This would be very nice technology in the home, but I bet it's going to stay in theaters for some time. For the home, there may just not be the 'buy-in' with the decoding needed, amount of speakers, and cost of adding to processors (think of all the amps needed). I think most are still sticking with 5.1 and only a few are going above that (7.1, 9.1 and 11.1). WAF, as mentioned above, will be a major stumblig block for many as most folks have general shared rooms, not a dedicated room. Just my opinion...


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## sdurani

B- one said:


> Small problem I can see if it happens WAF. Hey honey we need more speakers.


Don't need more speakers. The advantage with Atmos is that the rendering engine will know where each of your speakers are (where = distance, elevation, azimuth). This will allow the renderer to send individual sounds (objects) to whichever speaker or combination of speakers it needs to image the sound at the intended location. So even with your current speaker layout, Atmos will get you closer to what the recording engineer intended you to hear.


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## morca

I just installed the last of 64 speakers,when the HT is fully ready i make some pic,s for you all :bigsmile:


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## lcaillo

Statements like "Independent of room size and the acoustic characteristics of the room, Atmos can be calibrated to work in an optimal way." seem like unnecessary hype to me. No matter what you do with encoding, decoding,calibration, and playback, if you are listening in a room the room does have a significant impact. You can only do so much with calibration no matter how many speakers and how much power you use.


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## tonyvdb

Another issue I see with adapting the Atmos in a home theater is space limitation. Adding more speakers that close to the others would be a nightmare to prevent all kinds of phasing and null issues. In the theaters the speakers are still probably 10ft or more apart eliminating many of those problems in the home environment this would not be the case.
I can see them adding two more channels for overhead but anything more would involve the complete redesign of Audyssey, YAPO and the others. Not to mention more amps in the receivers and where do you put the extra binding posts on the back of a receiver for those speakers (its getting crowded as it is)


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## sdurani

lcaillo said:


> No matter what you do with encoding, decoding,calibration, and playback, if you are listening in a room the room does have a significant impact.


The reason the room has significant impact is because of reflections. Since reflections have to take a longer/indirect path to your ears, they lose energy along the way and aren't as loud as the direct sound from your speakers. As the number of speakers go up, the impact of the room goes down (with enough speakers, direct sound ends up swamping out reflected sounds).


tonyvdb said:


> Adding more speakers that close to the others would be a nightmare to prevent all kinds of phasing and null issues.


Only if they're playing the same signal. If they're playing different signals, how can that cause cancellation nulls? And even when they're playing the same signal, it's only a problem with 2-3 speakers. Once you add more, the phasing/combing evens out (at that point you don't even need to time align them individually).


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## tonyvdb

sdurani said:


> Only if they're playing the same signal. If they're playing different signals, how can that cause cancellation nulls? And even when they're playing the same signal, it's only a problem with 2-3 speakers. Once you add more, the phasing/combing evens out (at that point you don't even need to time align them individually).


To a point yes but that still does not change that adding that many channels to a receiver is going to be near impossible given the space limitations and needing to redesign the room EQ systems.


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## sdurani

tonyvdb said:


> To a point yes but that still does not change that adding that many channels to a receiver is going to be near impossible given the space limitations and needing to redesign the room EQ systems.


More outputs will require more back-panel real estate, there's no way around that, short of those annoying DB-25 connectors and breakout cables: 










However, with the analogue sunset being imposed on the industry, component and composite video connections are starting to get fewer and fewer with each new receiver line; same with stereo analogue audio inputs. A pre-pro that had 3 component inputs and one component output (not uncommon) can use that exact same space for 12 audio outputs. Do the same with composite connections and you're up to 16 output connections. And this is in addition to the 7.1 outputs already on the pre-pro. Now you're up to 24 channels, without any additional back-panel space than current pre-pros. 

As for room correction, there's no need to redesign: same algorithm, more channels. If back in 2010, Denon could deliver 13 (11.2) independent channels of Audyssey's best room correction (XT32) for less than $2k, then by the time the consumer version of Atmos arrives (2015?) there shouldn't be a problem EQing way more channels.


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## tonyvdb

Agreed but that means you will need 32 channels or more of outboard amplification as the receivers cant power more channels due to current limitations of power supplies that are in them.


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## lcaillo

Actually, Tony, the power supply should not be any more of an issue than it is now. the total power out should be about the same, just distributed over more speakers. The space to do discrete channels, connections and amplifier stages, will mean bigger components physically.


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## tonyvdb

But we all know that already in most receivers its the power supply that is the weak link in supplying enough to the amplifiers. Most receivers cant do all channels driven as it is without a 20% (aprox) drop in its rated output without distortion. How is more channels going to be the same?


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## sdurani

Don't know if initial implementations will be "32 channels or more", but the desire to have more than 7 or 9 amp channels in a receiver could lead to more use digitial amplification. With the kind of efficiency they have compared to regular amps, power supplies won't be a problem.I don't know if you remember those Panasonic 7.1-channel receivers from several years ago that used to only be a couple inches tall.


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## J&D

More amp channels a problem? HT enthusiasts everywhere cannot wait to add additional channels of external amplification. High efficiency surrounds driven by relatively low wattage amps is all that should be required to achieve good results in an average room. This would not be a technology widely adopted for the masses but geared toward those with dedicated rooms and the flexibility to configure them as required. The key to success is that it has to provide a dramatic improvement over the current formats. 

At a minimum it would have to be akin to going from Dolby Pro Logic to Dolby Digital and I would hope the final result would be something even more dramatic.


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## lcaillo

tonyvdb said:


> But we all know that already in most receivers its the power supply that is the weak link in supplying enough to the amplifiers. Most receivers cant do all channels driven as it is without a 20% (aprox) drop in its rated output without distortion. How is more channels going to be the same?


Assuming you have amplification in a 7 channel system that is adequate to drive the system to the level you want, and the power supply is up to the task, going to more channels to produce the same SPL does not necessarily require more power if the speaker efficiency stays the same. The power will be distributed differently and the power supply in the amp will need to deliver the same amount of current. You don't need 64 channels of 100 watts each.


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## bkeeler10

Well, I for one am quite excited about the prospect of Atmos in the home. There are some obstacles to overcome obviously, and it won't be for the average guy who is casual about his home theater. But for most of us who frequent this forum and take home theater seriously, I would think it will appeal at least in concept. Especially for those who have dedicated rooms. It will of course involve an extra outlay of money. I'm sure some of us will come up with a way!

I wonder if a larger and more well-damped room would be increasingly important to the success of an Atmos roll-out in a home theater. Ostensibly the processing will make it sound essentially the way it should regardless of room size or speaker count, but I suspect a larger room with well-controlled reverb would give a better result. 

I can envision a larger theater with the typical three front channels, two pairs of overhead speakers, three pair of speakers on the side walls (one forward of the listener, one to the sides, and one behind), plus a pair of rear surrounds. That's a lot of speakers and a lot of amp channels, but if it is all discrete and specifically addressed in the encode (as opposed to somewhat arbitrary processing not specific to the mix, like with the current 9.1 and 11.1 matrixed solutions), I think it would be amazing.


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## sdurani

bkeeler10 said:


> I wonder if a larger and more well-damped room would be increasingly important to the success of an Atmos roll-out in a home theater.


I can understand 2 speakers being swamped by a room full of reflections coming from different directions. But when you have 12 speakers located in different directions, will all that direct sound still be swamped by reflections? 

IF Hass is to be believed, those reflections would have to be louder than the initial sound from the speakers in order to compete for your attention. What is the likelihood of that? 

As counterintuitive as it may seem, adding more speakers might make dampening less necessary, since you'll be hearing more direct sound than reflections. Atmos could end up being more beneficial to normally furnished living rooms than finely tuned dedicated HTs.


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## bkeeler10

sdurani said:


> I can understand 2 speakers being swamped by a room full of reflections coming from different directions. But when you have 12 speakers located in different directions, will all that direct sound still be swamped by reflections?
> 
> IF Hass is to be believed, those reflections would have to be louder than the initial sound from the speakers in order to compete for your attention. What is the likelihood of that?


With a speaker playing in a room, there is a distance from that speaker known as critical distance. It is the distance at which the direct sound from the speaker and the combined sum total of the reflections in the room (the reverberant sound) are equal in SPL. If you are closer to the speaker than the critical distance, the SPL from the speaker is louder than the SPL from the room reverb. Conversely, if you are further away from the speaker than critical distance, you are hearing more SPL from the room than directly from the speaker.

You may be surprised how short the critical distance is, even in most small rooms with fairly low reverb time. For example, in a 3100 cu ft room with a rather short reverb time of 0.5 seconds, and with a speaker having a 100 x 60 radiation pattern, the critical distance is only 7'. This is all frequency-dependent, so I'm generalizing here.

Now, in Atmos if you're using overhead speakers they're likely to be within critical distance in our example room. But the front three speakers probably are not, and the speakers behind also may not be. So for at least some of those speakers, their direct output would be less at the listening position than the room's reverberant field.

I would argue that a system that is very specific about which speaker(s) it places sounds in would want to rely less on room reflections to achieve its desired effect. Because the location of a sound can be more precisely placed, excessive reverb would only smear that effect. That's my theory anyway. 

Didn't mean to drift so far OT. I think Atmos in the home would be an improvement in most any system and I hope it shows up soon. I've yet to hear it in a theater, but it is really the only thing motivating me to go to the theater these days. I do have an Atmos theater fairly close by, so I need to find the right movie and go hear it. I wonder if Hollywood and theater companies see technology like this as a way to get more people to theaters than would otherwise come without new technology. In that sense, it may be in their best interest to keep it in the theater only for as long as possible. But I'm hoping it's available for consumer use soon.


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## sdurani

bkeeler10 said:


> I would argue that a system that is very specific about which speaker(s) it places sounds in would want to rely less on room reflections to achieve its desired effect. Because the location of a sound can be more precisely placed, excessive reverb would only smear that effect. That's my theory anyway.


Understood. For me it's not a question of relying more or less on room reflections, but instead those reflections becoming less relevant as the number of speakers increases. The ratio of reflected sound to direct sound starts to skew in favour of the latter. Besides, excessive reverb is not going to be a problem in normally furnished, residential sized rooms. The listening space would have to be much larger to get true reverberation.


bkeeler10 said:


> I've yet to hear it in a theater, but it is really the only thing motivating me to go to the theater these days. I do have an Atmos theater fairly close by, so I need to find the right movie and go hear it.


Don't know if _'Oblivion'_ is the right movie to hear it, but it is right around the corner AND the director claims is first movie to be mixed in Atmos from the ground up (previous titles already had a channel-based mix but pulled out a few pans around the room and overhead elements for the object-based mix). So there's your excuse to finally catch an Atmos mix in the next couple weeks, especially since you have a theatre nearby. 

One of the advantages of being in the Los Angeles area is that there are half a dozen Atmos-equipped theatres around me, so I've been able to catch most of the Atmos mixes so far. They vary just as much as channel-based mixes do. Watching _'G.I. Joe'_ this weekend, I wondered why they even bothered with an Atmos mix (so loud and noisy that it was difficult to appreciate the panning and overhead effects).


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## 8086

I doubt I will ever expand my system beyond 7 speakers + subwoofer(s) to ever make atmos worth my time or money. I'll take five quality speakers over quantity (9) anyday.


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## jkenefake

I actually see Atmos being widely adopted in home theater gear. The great thing about Atmos is its ability to down-mix to anything, 7.1, 5.1, 2.0, etc. An Atmos processor is the only thing required for a system to be considered "Dolby Atmos". Therefore, you could have 7.1 and 5.1 receivers with Atmos that simply down-mix the stream. Even a soundbar with an Atmos processor could happen. I can see it becoming a big marketing thing for A/V gear. i.e. "this home theater in a box system offers Dolby Atmos." Systems like that would probably not sound any different than a Dolby Digital 5.1 system, but its all in the marketing. Its kind of a sad use of the technology, but if it gets more systems out there, that lowers the price for everything.

As far as scalability, I could see higher range receivers that offer an add-on component that uses a digital connection but outputs additional channels with or without amplification. The main receiver would house the main Atmos processor and be set up for a standard 7.1 output with 1 to several add-ons to bring the system up to the desired number of channels. This is all very doable. 

Of course, before this happens, 2 things need to happen. Blu-ray needs to add support for Atmos, which I believe is not asking too much, and the cost of the Atmos processor will need to be cheap enough.

Boy, I hope I'm right about this. I saw (or heard) Hobbit in Atmos and thought it was really great. Seeing Iron Man 3 on Wednesday, hope it uses the technology well. This will be the future of cinema audio.


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## tonyvdb

On the flip side this could be what the theaters need to keep customers going just like D-Box seating so it may be kept there and not (for several years anyhow) be seen available to home theater.


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## fitzwaddle

tonyvdb said:


> On the flip side this could be what the theaters need to keep customers going just like D-Box seating so it may be kept there and not (for several years anyhow) be seen available to home theater.


Yeah that was my thought as well. Would love to be wrong though!

I'm thinking monoblocks x 32 or so.


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## jkenefake

tonyvdb said:


> On the flip side this could be what the theaters need to keep customers going


I don't see Atmos being a big draw for the vast majority of the public. The theater near me doesn't even list Atmos with the showtimes. I think 3D and IMAX will be the thing that keeps people coming.


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## Kal Rubinson

tonyvdb said:


> On the flip side this could be what the theaters need to keep customers going just like D-Box seating so it may be kept there and not (for several years anyhow) be seen available to home theater.


1. There is already an ATMOS consumer offering in the works albeit at a price that excludes most consumers.
2. I cannot imagine that not enough of the vast unwashed will distinguish ATMOS from surround/loud to make a commercial difference.


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## sdurani

jkenefake said:


> Systems like that would probably not sound any different than a Dolby Digital 5.1 system...


I'm not so sure. Even with current 5.1 or 7.1 speaker layouts, the Atmos renderer would have the advantage of knowing where your speakers are. So, for example, if the renderer notices that your side speakers are a couple of feet above ear level, then it can route height information to those speakers for overhead imaging rather than routing those sounds to three speakers at ear level in front of you.


jkenefake said:


> Blu-ray needs to add support for Atmos, which I believe is not asking too much, and the cost of the Atmos processor will need to be cheap enough.


Though it's not part of the current Blu-ray spec, it seems doable on that disc. This year at CES, Dolby demonstrated Atmos using a Blu-ray disc as the delivery media, played on a consumer BD player, connected to via HDMI to a commercial Atmos decoder. 

As for cost, if the price of a typical BD player (just a few years after introduction of the format) is any indication...


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## Owen Bartley

bkeeler10 said:


> I can envision a larger theater with the typical three front channels, two pairs of overhead speakers, three pair of speakers on the side walls (one forward of the listener, one to the sides, and one behind), plus a pair of rear surrounds. That's a lot of speakers and a lot of amp channels, but if it is all discrete and specifically addressed in the encode (as opposed to somewhat arbitrary processing not specific to the mix, like with the current 9.1 and 11.1 matrixed solutions), I think it would be amazing.


I like the sound of this. But, as others have pointed out, its the scalability that Atmos could offer that is the big benefit. I'm sure a future version of Audyssey (or a proprietary Atmos tool) could detect where the speakers you have are, and by defining your seating location, you could have custom-routed x-y-z localized sound.


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## Shack666

64 channel, wife friendly... Time to start digging...

Cheers,


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## 8086

Shack666 said:


> 64 channel, wife friendly... Time to start digging...
> 
> Cheers,


Wife friendly only if you use high quality in wall and in ceiling speakers.


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