Bad Atmos!! Is a 5.1.2 Dolby Atmos Setup any Good?

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[TheReverendSlim]

Actually, you're SLIGHTLY wrong on the way this gets folded down with Atmos. Basically, it's a range limitation based on the number of speakers you have. I'll try to explain:

First, let's compare 5.1 to 7.1 in an Atmos context, setting aside the heights for now. The Atmos decoder sees the front soundstage as 0.0 on the longitudinal, with your REARMOST speaker pair as 1.0. So with 7.1 (the ideal), your rear surrounds represent the coordinates furthest back in the room. Accordingly, static objects placed at rear surround play back in the rear surrounds, side surround position in the side surrounds, etc. Now, compare that to how it deals with 5.1. In this case, the SIDE surrounds will be the range limitation, meaning they are the "1.0" coordinate. Here's why that's important: Because of the way this works, static objects for rear surround are now played through the side surrounds. BUT... static objects for the side surrounds are now no longer played back just by the side surrounds, but instead imaged between each side surround and its adjacent main. To clarify, a left side surround object in a 5.1.x Atmos layout will be played back by both the left main and left side surround so that it images between them. This is why 5.1.x layouts tend to have the side surrounds a bit further back than where they would be in a 7.1.x layout.

Now that you've wrapped your head around that, let's consider the heights. The same range limitation issue applies. So in a bone stock x.x.4 layout, the decoder considers the front heights (whether in front height or top front position) to be the 0.0 coordinate and the rear heights (whether rear height or top rear) to be the 1.0 coordinate longitudinally. Note: This is only for objects AT THE MAX Z coordinate of 1.0. So on the Z axis, ear-level channels are 0.0 and heights are 1.0.

Now let's consider what the range is with a x.x.2 layout. Basically, as there are not two pairs of speakers for it to set this range between, any object at max Z will be played back solely by the 2 heights at top mid. It doesn't matter what their longitudinal coordinate is... The entire longitudinal range from 0.0-1.0 is represented by those two speakers AND ONLY THOSE TWO SPEAKERS when at max Z. Static objects at max Z in the top rear position will play back identically to static objects at max Z in the top front position.

So in a static 7.1.2 mix (as many are, sadly), a 5.1.2 layout will play the heights at top mid, rear surround at side surround, and side surround a bit forward of side surround by using the mains. You can confirm this using Dolby's 7.1.x test tones on a 5.1.x layout. Where things get interesting for a 5.1.2 layout is for any DYNAMIC objects below max Z. So let's say you have an object placed directly above the expected left side surround position at 0.5 on the Z axis. On a 7.1.2 setup, this would be played back half by the left side surround and half by the left top mid. On a 5.1.2 layout, however, the side surround position is represented between the physical side surround and the front soundstage... so this same object at 0.5 on the Z axis would basically be played 50% in the left top mid, about 30% in the left side surround and about 20% in the left main (because if I recall correctly, "side surround" expected position is at 0.6 longitudinally, in line with the "reference listening position" of the theatrical layout).

So the weakness of a 5.1.2 layout really only occurs with objects that are at max Z, as you will have no longitudinal movement for objects at max Z. Dynamic objects otherwise that are between 0.0 and 1.0 on the Z axis get adequate representation by steering using the adjacent channels. The side surrounds don't necessarily "do the duty of three speakers" as you're saying. But they do get used to help steer any rearward sounds that AREN'T at max Z. The mix doesn't have to be optimized between the layouts... but they do CHECK the mix on the lower speaker counts to make sure the general effect is still there and tweak object placements if needed.

What does this all mean? If you are doing a 5.1.2 layout in your room, make sure you don't put the side surrounds at the 90 degree position they would be in a 7.1.x layout. Put them at the 110-120 degree range so that the rear max range is actually behind you slightly. Then your "side surrounds" will image between the physical side surrounds and mains so that the image is closer to the 90 degree placement in a 7.1.x layout.

[hongliangisrude]

When I went 5.1 to 5.1.2, it was significantly better in terms of immersive feels. I haven't tried x.x.4 before but 5.1.2, to me is definitely worth the upgrade from 5.1 if that is all you can manage

[RichardBurgessMD]

Isn't Atmos an object based system? I understood that the mixing engineers put the objects in 3D space. They don't need too worry about the speaker setup like they did in the old days The processor decides how to interpret that for your particular speaker configuration. This whole concept of the mixing engineer "optimizing" for a particular arrangement of speakers is the old way of doing things in a channel based system. Seems like the people doing the optimizing should be the processor software engineers. Likely a combination of Dolby, DSP company, and sound united engineers.

[doublet]

I started with a 5.2.2 with rear height. A year later I added 2 front height and the difference was astonishingly better & I thought it sounded great before. Soon I'll be upgrading to a 7.4.4 & I can't wait!

[carlcameron]

My favorite atmos movie is still A Quiet Place. The Atmos and LFE are off the chart 🔊🔊🔊🔊

[willyrags]

The referrence home setup for atmos is 7.1.4 when it first came out. It may have changed. While I certainly agree that a 5.1.4 will sound slightly better than a 5.1.2, you cannot leave the side surrounds at ear level with a 5.1.2. You will have to raise the surrounds slightly above your main listening postion and slightly behind to create a better transition of sound.

[JEdmund]

I've got a 5.1.2 with Polks and a Sony STRDN1080. I love it! Usually the sound just comes across blended everywhere nicely, with moments that are clearly overhead. When watching 5.1 tracks I really notice the difference as it sounds more in front of me than enveloping me. Super happy with upgrading my receiver and adding ceiling speakers.

[SqueamishPuppet]

I've got a 5.1.2 and even though I don't have rear highs I hear things that should be in the rear high channels and it sounds higher than the speakers themselves so the effect works. I also hear things pan through the rear as it would with 7 channels. I really think it depends on what speakers you have. If you can localize your speakers than it's going to sound disconnected.

[paulcarroll]

The more speakers you have to mix for, obviously you’ll get a more immersive experience but your processor plays a very large part.

I have a 5.1.2 with the surrounds (floor) behind at 45 degree to listening position and my Atmos are 15 degrees forward of listening position above on the ceiling. I’m perfectly happy with my set up, it’s great and matches the space/layout.

[drakestevens]

As several people have pointed out, the sounds-tied-to-channel mixing doesn't apply to Atmos, as it is object based and the engineers mix using spatial placement rather than sound panning. What I'd add is this is why it is important to design your setup specific to your listening space. I have a similar space to what you described you have. I live in an apartment, which presented multiple obstacles. I have limited space, so my sofa is almost against the wall, with about 9 feet of space between the entertainment center and the sofa. I also have textured ceilings that prevent effective use of up-firing modules, and I couldn't install speakers on the ceiling or run wires in the ceiling or walls. My solution is very much like yours, I have a 5.1.4 system, with height speakers and surrounds mounted to the walls and wires ran using cable concealer tracks. When I installed my speakers, I did a LOT of testing. I tested multiple placement positions and angles before I mounted everything. It took me two weeks to decide on what sounded best. My space is far from ideal, but with my installation it sounds as good as I believe it possibly can, given my resources and space limitations. I've turned off my rear height speakers to see what it sounded like, and while it is different, it isn't a jarring difference. My surround placement is optimized more for general directional sound rather than point source, and that alleviates some of those "panning" issues you described. My advice to anyone setting up an Atmos system is research, test, and be patient. You'll find what is right for your unique space.

[EHphonehome]

I just have standard 5.1 at the moment, but I feel the optimal placement for 5.1.2 would be center height speakers. Having the 2 heights only in the front or rear seems like they would unbalance the sound field like you describe in the video at 7:30

[bearlycamping]

So glad I have a 5.1.4 set up, don't have the space for 7 ear level speakers. All Kef baby!!

[papapun]

if you do not have a dedicated room set up for HT, the secret is to use omnidirectional speakers for front and rear, then tone match a center or get a center you like, throw in 2 subs for even bass and call it a day.

point is not be able to pick out your speaker when you hear a sound. its about being able to hear the sound between 2 speakers.

[zacknichols]

I have a 5.1.2 setup with the atmos speakers only in the rear. I don't know if that is supposed to be terrible, but I think it still sounds great. Better then my old 5.1.0, it has a lot more seperation.

[Ladybugsammiie]

I just went from a 5.1.2 to 5.1.4. The difference is really amazing. I've also been mainly listening with Auro 3d (on your suggestion) and it just makes everything I watch that much better. Thanks for the tip buddy!

[craigosterberg]

7.1.2 I’ve added Dolby atmos speakers and I notice a big difference from the sound bar I had before. I now have 2 bookshelf front speakers 2 Atmos . Center channel and 2 rear surround speakers and subwoofer.

[SpencersStuffTV]

My goal is to get a 7.1.4 setup. I have just a 5.1 setup and I feel like there are massive holes in my sound. One day. One day. Happy New Year!

[JoseRuiz-ffzb]

Techno Dad, I discovered in a sound test with two receivers and I found that if you set the speakers to "front height" or "top front" the sound is as you said but if you set it to "top middle" the sound of the height front and height rear are heard in the "top middle" do the test.

[ferdys]

Have 5.1.4. setup nowhere near perfect bcs my room layout is crazy. But still enjoying it alot :D

[tomninos]

I have noticed this as well. It also depends on what you tell your receiver you have as far as where your Atmos speakers are and even what movie you play. I have a Denon AVR 3700H running a 7.2.4. My Atmos speakers are set up to where the layout really is front ceiling speakers and rear height speakers Because of where they are located in my room. So I have two different presets for Audyssey But I have saved three different presets in the Audyssey app. One that has them set as 4 high channels. One that has them set up as 4 top/ceiling channels. And one that has them set up as 2 top/ceiling fronts And 2 rear heights. When playing my 4K disc of No Time To Die I get different sound coming out of those channels depending on which preset I use or upload. In the scene where Bond and Paloma are talking in the Spector club with on the earpieces if I run the front And rear height channels the dialogue clearly comes out of all 4 channels. But in the same scene using the preset as 4 top/ceiling channels The dialogue only comes out of the front ceiling channels and not the rear. Same thing goes for the other preset where I have Front ceiling/top and rear height. It only comes out of the front Atmos channels. This doesn’t make any sense to me that the preset with all 4 height channels actually sounds better. Some Atmos mixed movies sound better in the different presets and some sound exactly the same and it doesn’t make a difference. One would think that having them as all ceiling channels would be optimal but that’s definitely not the case. Sometimes having them is all Heights sound much better and more dynamic. It can be frustrating. I usually just leave them on the height preset as opposed to the top/ceiling preset because it seems to be more consistent. Anyone else experienced this or test this? I don’t think it has anything to do with the Denon receiver. I think it has to do with how the Atmos is mixed. Another example is the last mission impossible movie on 4K DVD. The helicopter scene towards the end. No matter which preset I use it sounds amazing with the helicopter blades going overhead etc. but it sounds the same no matter which preset I use.