Atmos in 5.1.2: where does the top rear audio go?

[ar surround]

Dolby themselves refers to the 7.1.2 as the bed. This is correct terminology.

https://professionalsupport.dolby.c...rence-between-beds-and-objects?language=en_US

"A Dolby Atmos input bed can be 2.0, 3.0, 5.0, 5.1, 7.0, 7.1, 7.0.2, or 7.1.2. Distribution of the bed in the Renderer is defined by the number of speakers in a particular room."

Anyone else's head spinning right now?

 

[sjcorne]

Anyone else's head spinning right now?

I wouldn't get too hung up on the whole bed/object thing, as it's really inconsequential from the listener-end. We can't tell from listening to encoded files (either lossy DD+ or lossless TrueHD) on our home systems whether the engineer has used just the bed, just objects, or some combination of both - but sometimes you can make an educated guess based on certain mix choices.

The main disadvantage of only using the bed is that you're always stuck in a 7.1.2 environment, even if you have more speakers in your setup (7.1.4, 9.1.4, 9.1.6, etc). So if you're mixing on a 7.1.4 array and you pan a backing vocal to the top, it will stay suspended between the front and rear height speakers. You can only control its left/right position, not front/back. If you wanted a specific sound to emanate only from the front or rear heights, or just in one of the top corners, you'd have to use an object.

 

[himey]

My amp allows me to specify the physical location of my two height speakers, either front wall, front ceiling, middle ceiling or rear ceiling. Choosing one of these options controls what audio is actually sent to the speakers.

I have tested two Atmos receivers, a Yamaha and a Denon, and both of them ignored the front wall setting, and treated a 7.1.4/5.1.4 Atmos test signal the same as if you selected the two height speakers to top middle. All four top test signals came out the front height speakers and were not re-routed to any of the surround floor speakers. Dolby's advice for only 2 top/height speakers, is to place them above the listener, in the center of the room, as you noted.

I did the same test, with the same two receivers, using DTS-X, and the results were different, and as expected. When you only use two height speakers and set them as front wall height channels in the setup menu, DTS-X will send the rear two height signals in a 5.1.4 test clip, to the floor surround speakers in the sides/back.

 

[quadrifonico]

Hi all,

I have a 4.0.2 setup. Four speakers on the ground in a square and 2 speakers above the two front speakers identified as top fronts in my AVR (Marantz cinema 30). When I run the speaker check from Dark Side of the Moon 50th anniversary edition, the top rear audio is played in the top fronts. This confuses me; my assumption was that audio from the top rears would go to the surrounds. Similar as the left/right side audio is played via the rear speakers in my setup.

Are there forum members with a x.x.2 setup that can confirm that all 4 top audio signals are played by the 2 speakers? Or is there a setting I missed.

It is great that I get as much use of those tops as possible, but I wonder if it doesn’t mess up the intended placement. For instance, backing vocals from the rear tops would be great, but in my situation they would play from the front tops and that might not combine well with any backing vocals in the surround rears.

nothing gets lost; usually the rear heights parts are played by your rears, "down-mixed" if you prefer to say, depends on your set up the receiver would do the best to give you the best spacial representation. it is still Atmos, yes

 

[nikomen]

These two pictures are about 5 years old and things look a little different at the front, equipment wise, but we are not talking about that.

My seat is about middle of room, if you plumbed straight down my front heights would be about 3.5' in front of my chair, if you plumbed straight down my rears would be about 3' behind my chair.
The speakers in ceiling have movable/adjustable center tweeters and they are angled manually towards my chair.

My experience: my height speakers are farther distance from my head than the floor speakers. I have the height speakers +6db as I want to hear the heights without exception.
Atmos has so many variations as to how it ends up to the listeners ears, some are great and sum are duds and everything in the middle. If you are laying out a room, you basically want to lay out like mine. My room is 12' front wall X 14' long and 8' tall ceilings.
This configuration is close to near field listening, but plenty big enough to not be nearfield.
Metered amps are very good, especially when you are beginning Atmos, it mentally verifies what you think you hear.
I have 5.1 in my car, now that is nearfield listening and sounds really cool.
If I had a real big room, oh my, that would cost some bucks.
Final note; many times the signal is Dolby Atmos but there is nothing in the heights, so that can mess with your mind also.

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What speakers do you use for your height channels?

 

[AudiophileStyle]

I wouldn't get too hung up on the whole bed/object thing, as it's really inconsequential from the listener-end.

100%!!!

I’ve been meaning to post something like this. Thank you.

We all listen to mixes where a 7.1.2 bed was used and mixes where a 0.1.0 bed was used with the rest being objects. It matters not.

I totally get listeners trying to understand the technical details more, myself included, but in this case the details are misleading people. As listeners we need to forget about beds and objects. The only way to know how a mix used them is to ask the mixing engineer. Even then, it doesn’t really matter for our purposes.