# Dolby ATMOS General Info and Applications Thread



## Lumen (May 17, 2014)

Hello! I was reading a thread which touched base on Dolby ATMOS. That raised a few questions in my mind, so instead of hijacking that thread, I did a search on our forums but could only find ATMOS discussions about specific issues and problems. 

So I decided to start a thread for those of us not so well-versed on Dolby ATMOS encoding, equipment, and setup. Boy, is this going to be embarrassing if another thread's already been started! If not, I'd like to start off by asking a few ATMOS questions I hope someone can help with:
What does the last number in 7.1.4 and 5.1.2 mean? Is it the number of ATMOS speakers used?
How important is it to match the ATMOS speakers to the others? Is it same importance as matching the mains and center? Why or why not?
Do the ATMOS speakers have to be in-ceiling, or can they be wall-mount like surrounds? Pros & cons?
Do I need a new player and AVR to decode the ATMOS signal?

TIA


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## Peter Loeser (Aug 11, 2012)

1. Yes, the last digit represents the number of height channels being used
2. Same as matching surrounds to mains, but not quite as important as matching center to mains (in my huble opinion). Having 100% identical or matched speakers throughout your system is always ideal, but rarely practical. If possible, I'd recommend sticking with the same brand as you mains. Room correction/EQ can help as well if your speakers are not perfectly matched.
3. In-ceiling (or on-ceiling) is preferable. You could make wall-mounted speakers work, but I don't think you'd get the same effect.
4. A Dolby TrueHD compatible player will work, not need to buy and Atmos specific player.


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## Lumen (May 17, 2014)

Thank you, Peter! Oh and by the way, nicely thought out and executed HT gear and room. Where in the world did you get the idea for such symmetry :whistling:

I see you're considering adding ATMOS. Have you found out enough about the finer points of speaker location (e.g. directly above mains, along vertical plane of screen, further out into room, etc.)? How do the preferences change as speaker count is increased? What's the maximum recommended number?

Also, how does the AVR hook-up work? It seems you would need an ATMOS-ready AVR; otherwise, how could you steer the ATMOS signal to the proper preamp output?


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## Peter Loeser (Aug 11, 2012)

An Atmos capable receiver or processor is essential. There are plenty available now, some capable of up to 7.1.4 or 9.1.2.

Regarding speaker placement - Dolby has created a guide here, which covers the different configurations.

The nice thing about Atmos is it can be scaled as small or big as you want. While Atmos can handle up to 32 channels for home theater, even a 5.1.4 setup will give excellent results in my opinion.


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## Lumen (May 17, 2014)

For an x.y.4 configuration, Dolby recommends two in-ceiling speakers forward of the LP and two more slightly flanking it. I think a double pair Atmos system would be more immersive and more fun than a single pair setup. This would especially true for the ceiling-mount solution. But what's this about "Atmos-enabled" mains and/or tabletop modules?

Okay, I suppose some people would prefer the mains-enabled boxes for aesthetics or add-on modules for installation convenience. But HT enthusiasts adding sound sources that purposely bounce sound off the ceiling? That's a compromise akin to sound bars which bounce sound off the walls in an attempt to create the illusion of sound coming from behind. Even if the bouncy-bounce drivers were highly directional and precisely aimed, I can't see an enthusiast taking them seriously. And as you mentioned in Item-3 of Post #2 above, the effect would not be the same.

In any case, I won't be adding Atmos any time soon, as I just upgraded my pre/pro for better auto-EQ and for 4K-readiness. The unit isn't as future-proof as some, but I think the HT arena has slower-paced advancements than the computer or cell phone worlds. Ahh, if only to throw the budget out the window :spend: :nono:


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## Peter Loeser (Aug 11, 2012)

BlueRockinLou said:


> I think the HT arena has slower-paced advancements than the computer or cell phone worlds.


Yes, although it has accelerated the last couple years. Still no way it will keep up with cell phone tech advancement anytime soon.


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## NBPk402 (Feb 21, 2012)

I would like to see multiple subs in Atmos.


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## Peter Loeser (Aug 11, 2012)

ellisr63 said:


> I would like to see multiple subs in Atmos.


You mean more than one discrete LFE channel in the soundtrack?


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## NBPk402 (Feb 21, 2012)

Peter Loeser said:


> You mean more than one discrete LFE channel in the soundtrack?


For tuning... Like the 4520 has.


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## Peter Loeser (Aug 11, 2012)

ellisr63 said:


> For tuning... Like the 4520 has.


Not sure I follow. You want two sub outputs from the receiver or you want two sub channels on the soundtrack?


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## NBPk402 (Feb 21, 2012)

Peter Loeser said:


> Not sure I follow. You want two sub outputs from the receiver or you want two sub channels on the soundtrack?


2 sub outs on the receiver. :T o far Atmos AVRs only have spec for one sub, which means you have to manually calibrate each sub.


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## Peter Loeser (Aug 11, 2012)

ellisr63 said:


> 2 sub outs on the receiver. :T o far Atmos AVRs only have spec for one sub, which means you have to manually calibrate each sub.


Both the Yamaha A3040 and the Denon X4100 I just reviewed have dual sub outputs which are calibrated independently. Granted they are higher level receivers but not the only ones that offer both features.


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## NBPk402 (Feb 21, 2012)

Peter Loeser said:


> Both the Yamaha A3040 and the Denon X4100 I just reviewed have dual sub outputs which are calibrated independently. Granted they are higher level receivers but not the only ones that offer both features.


Why are they not counting the subs as 2 then in the Atmos adverts... example 7.1.2?


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## Peter Loeser (Aug 11, 2012)

Because the soundtrack still only has one discrete LFE channel. HDMI handles 8 discrete audio channels - up to 7.1 on a Blu-Ray for example. An Atmos soundtrack still uses the same 8 channels, but with metadata that an Atmos decoder turns into objects in 3D space. So for example, the *7.1*.4 represents the number of discrete channels in the source, and the 7.1*.4* represents the height speaker count. The nomenclature combines two things that are somewhat independent of each other. You can play a 5.1 soundtrack through a 7.2.4 system, and even with separately calibrated subs they are both still receiving the same source signal. (Unless the AVR can set them up as left/right stereo subs). Essentially there is no such thing as a 7.2.4 soundtrack. (Just one example)


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## NBPk402 (Feb 21, 2012)

Peter Loeser said:


> Because the soundtrack still only has one discrete LFE channel. HDMI handles 8 discrete audio channels - up to 7.1 on a Blu-Ray for example. An Atmos soundtrack still uses the same 8 channels, but with metadata that an Atmos decoder turns into objects in 3D space. So for example, the *7.1*.4 represents the number of discrete channels in the source, and the 7.1*.4* represents the height speaker count. The nomenclature combines two things that are somewhat independent of each other. You can play a 5.1 soundtrack through a 7.2.4 system, and even with separately calibrated subs they are both still receiving the same source signal. (Unless the AVR can set them up as left/right stereo subs). Essentially there is no such thing as a 7.2.4 soundtrack. (Just one example)


:T:T


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## Lumen (May 17, 2014)

:T :T *+* :T Well put, Peter!

Now we need the industry to release ATMOS titles in droves; not just a few for early adopters. I don't profess to understand the marketing and economics of the business, but I think I understand they've fallen short of public expectation with true 7.1 formatted titles.


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## Lumen (May 17, 2014)

Oh my, have you heard Dolby wants to incorporate ATMOS into smartphones?! :rubeyes:

This has to be the HT enthusiast's equivalent of an audiophile's disdain for lowest-common-denominator MP3's.


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