informal survey: how many Atmos users adhere to Dolby height speaker layout and performance recommendations?

[krabapple]

Here are Dolby's 2018 Home Theater Installation Guidelines*
I'm breaking their height speaker recommendations into four key points.

1. Ceiling vs front wall mounting and directivity:
All of Dolby's diagrams (except ones using the bouncey Atmos Enabled floorstanders) show height speakers mounted on ceiling and firing directly down.
For this to work well, Dolby recommends them having a 'wide dispersion pattern' (They do not specify vertical vs horizontal dispersion)
If they aren't wide-dispersion then the speakers should be aimed a bit toward the MLP rather than firing directly down.

2. Left-right placement:
Dolby figures show left-right placement as being in-line with the FL and FR speakers.

3. Front-back placement:
Dolby shows recommended front-back placement a bit differently depending on whether 2 or 4 height speakers are used
-- for 2 speakers, anywhere from 65° in front to 110° behind (where directly overhead = 90°)
-- for 4 speakers, anywhere from 30° to 55° for fronts and 125° to 150° for backs

4. Frequency response:
Dolby only says:

Dolby Atmos audio is mixed using discrete, full-range audio objects that may move around anywhere in three-dimensional space. With this in mind, overhead speakers should complement the frequency response, output, and power-handling capabilities of the listener-level speakers. Choose overhead speakers that are timbre matched as closely as possible to the primary listener-level speakers.

(At least one study says height speakers that go much lower than 400 Hz are probably overkill.)


Perusing various room photos hobbyists kindly provide here on ASR and other forums, I see much evidence of philosophies about this that appear to differ from Dolby's.

So I'm curious, who's actually adhering to this, who's not , and if not, why?

(This constitutes research preceding my own Atmos setup attempt)





(*have these been superseded?)

 

[elguapo]

So I'm curious, who's actually adhering to this, who's not , and if not, why?

I did my best to let my 9.1.4 setup (including speaker placement, SPL calibration, dynamic range availability, speaker's FR and target room response) meets Dolby Atmos music studio minimum requirements.

 

[Fslag]

not, why?

People refuse to place them to Dolby spec. Intentionally.
Only reason I see why not.

I have pre wired a room that is fully to 9.2.4 atmos spec as per angles from listening position and yes the atmos speakers do line up with the fronts roughly. I choose 50 degrees as there's great debate of going closer together vs less and it's about finding the balance of speakers positioned EVENLY in the room over the listening position.
There is almost no circumstances where front heights do this.

 

[rolfrander]

There seems to be a bug in the link to the guidelines-pdf in the first post, this is the correct link:

https://www.dolby.com/siteassets/technologies/dolby-atmos/atmos-installation-guidelines-121318_r3.1.pdf

 

[Oddball]

Often it is not really possible to strictly follow Dolby guidelines for various reasons.

In ceiling placement is tricky. I opted for on wall placement with brackets that can be tilted horizontally and vertically. After some experimenting, I did find optimal angling for the speakers and "bubble" is great. Even if I move the MLP a bit, can re-adjust angles (levels will be auto-adjusted by AVR/AVP) and still make it work.

As far as size, it is possible to adhere to guidelines in a bookshelf system. But did not yet see anyone hanging 50kg towers as Atmos speakers. In that case, decent bookshelfs will do for Atmos and would not worry too much about the mismatch. At least I did not. Many will want to spend more for LCR and subs that carry most of the HT load, so by virtue of resource allocation, Atmos will not be of the same grade as LCR.

 

[JeffS7444]

I hadn't been aware of that guide.

((At least one study says height speakers that go much lower than 400 Hz are probably overkill.)

Thank goodness, because the PE-surplus ceiling-mount speakers that I'm using (actually bolted to the underside of shelves) are little more than sub-3" full-range drivers housed in angled plastic cabinets, which luckily, point in the right direction. Have sometimes thought to upgrade to something better and more adjustable, but these little guys seem to be working. Have yet to encounter Atmos height-channel content beyond faint ambient sound, but I know that the speakers are working, because I can hear them loud and clear during Audyssey setup.

 

[Talisman]

I'm also currently struggling with the Atmos setup. Having a small room, I initially opted for a 5.1(4).2
but I've noticed that I can't get a true sound bubble above my head. I'm switching to a 5.1.4 by moving the front Atmos speakers forward about a meter and positioning the rear speakers, which unfortunately, due to room requirements, will be almost at my height (front-to-back) and not truly rear.
For Atmos speakers, I'm using Micca MB42x G2s, which are small, respectable bookshelf speakers mounted on ceiling brackets that allow for precise angles. I'll add another pair and see the effect.
Despite Dolby's recommendations against it, I'd also considered trying just two bipolar ceiling speakers to try to widen the sound field a bit, but that would lose much of Atmos' ability to precisely position objects.

 

[antcollinet]

Often it is not really possible to strictly follow Dolby guidelines for various reasons.

This.

Small room. The speakers are where they can fit - and where I can be bothered to run wiring. Still seems to work quite well. No doubt I'd be blown away by a compliant set up.

 

[GS430man]

Atmos in-ceiling overheads are much easier to implement if you are in construction or are willing to open up the ceiling. Our Atmos room is a newly finished basement space that was designed for the purpose, so fairly simple to do. Our room complies to the Atmos layout and performance guidelines.

In-ceiling speaker retrofit for a drywall room is not overly complex but it can be tedious and messy, requiring some carpentry and drywall skills, plus access to an attic area and ability to route cables to your amplifier(s). Can be a DIY project or local contractor if you live near a city. If you live in an apartment or condo, or have stone/concrete materials, on-wall/on-ceiling speakers are a good choice.

 

[krabapple]

There seems to be a bug in the link to the guidelines-pdf in the first post, this is the correct link:

https://www.dolby.com/siteassets/technologies/dolby-atmos/atmos-installation-guidelines-121318_r3.1.pdf

Thanks, I've corrected it in the post

 

[krabapple]

Often it is not really possible to strictly follow Dolby guidelines for various reasons.

In ceiling placement is tricky.

I wrote on-ceiling , because I dont recall Dolby explicitly recommending in-ceiling. The main point being ceiling mounted, (whether in or on) , firing down.

 

[Fslag]

This.

Small room. The speakers are where they can fit - and where I can be bothered to run wiring. Still seems to work quite well. No doubt I'd be blown away by a compliant set up.

See my comment. People who refuse and this proves it. Room size isn't relevant. I'm going to be upgrading to a 7.1.2 in a single bedroom.

 

[middlemarch]

Mine is 9.4.6. Nothing in the ceiling. Front heights more or less in line with fronts, rear heights same. Middle heights mostly in line with L/R surrounds. All the heights have 5.25 woofers, so no full range, but Dirac Art so who knows. All pointed to MLP. Almost all Revel, sprinkling of NHT (my first love). Have not measured angles.

Damn, sounds good!

 

[antcollinet]

See my comment. People who refuse and this proves it. Room size isn't relevant. I'm going to be upgrading to a 7.1.2 in a single bedroom.

If you like.

But if you think one data point proves anything apart for that one data point, then you are not understanding data.

 

[DavidMcRoy]

My system complies as a 6.0.4 Dolby Atmos-compatible system...except that I do not use bass management. I have a so-called "passive preamp" in a two-channel stereo system with dual subwoofers. All surround channels basically run as a "sidechain," with the front left and right channels from an AVR processor feeding "the stereo" as a 2-channel stereo source. No other 2-channel stereo sources come through the AVR processor. They are all sources on the passive preamp.

 

[Oddball]

I wrote on-ceiling , because I dont recall Dolby explicitly recommending in-ceiling. The main point being ceiling mounted, (whether in or on) , firing down.

Indeed they don't make the distinction as there should be none acoustically. However, I rarely saw on ceiling open mount as people tend to prefer to hide them under the ceiling. I had on ceiling option, but opted for on wall for various reasons.

If you angle on walls properly (both horizontally and vertically) they will work quite well. I also did not measure angles but adjusted by ear. Couple of hours of listening while my buddy was kindly adjusting the angle of the speakers again and again. I think this is especially useful in multi-purpose irregular open spaces as Dolby recommendations are for regular room.

 

[krabapple]

OK so far I mostly see non-compliance driven by room constraints rather than any 'philosophical' difference with the Dolby recommendations.

What soemwhat puzzles me about Dolby's (admittedly less thatn fully detailed) spec is its persistent representation of height speakers firing directly down.
IOW, on-axis sound is a vertical line underneath the speaker. Not directed at the MLP.

Meanwhile, toe-in of 'bed' speakers is very commonly advised, and I've always done it, going back to stereo-only days. I prefer that more focused sound to the more reflective sound of speakers firing directly forward past my ear. (This of coures is also speaker-design-dependent to a degree.)

Is Dolby anticipating that Atmos height content is meant to be heard 'diffusely' ? Keep in mind Dolby seems very much to have 'home theater' in mind and seem to expect multiple listeners. In that case output of a heights array, all firing down, will inevitably be more 'on axis' for some in the audience than others.

At the same time, there are in/on ceiling-mount speakers that can be 'aimed' rather than fire straight down. These heights can be made to behave like 'toed in' bed speakers.

(And then there's wall-mounted, ceiling-proximate 'elevation' speakers, which are already angled down, but they aren't in the running for me, nor do they appear in Dolby specs.)

Are you guys aiming your heights at yourselves, or leaving them firing straight down?

 

[Oddball]

OK so far I mostly see non-compliance driven by room constraints rather than any 'philosophical' difference with the Dolby recommendations.

What soemwhat puzzles me about Dolby's (admittedly less thatn fully detailed) spec is its persistent representation of height speakers firing directly down.
IOW, on-axis sound is a vertical line underneath the speaker. Not directed at the MLP.

Meanwhile, toe-in of 'bed' speakers is very commonly advised, and I've always done it, going back to stereo-only days. I prefer that more focused sound to the more reflective sound of speakers firing directly forward past my ear. (This of coures is also speaker-design-dependent to a degree.)

Is Dolby anticipating that Atmos height content is meant to be heard 'diffusely' ? Keep in mind Dolby seems very much to have 'home theater' in mind and seem to expect multiple listeners. In that case output of a heights array, all firing down, will inevitably be more 'on axis' for some in the audience than others.

At the same time, there are in/on ceiling-mount speakers that can be 'aimed' rather than fire straight down. These heights can be made to behave like 'toed in' bed speakers.

(And then there's wall-mounted, ceiling-proximate 'elevation' speakers, which are already angled down, but they aren't in the running for me, nor do they appear in Dolby specs.)

Are you guys aiming your heights at yourselves, or leaving them firing straight down?

First Dolby is recommending placement in rectangular rooms. Also, ideal placement of all bed speakers is equal distance to MLP. Not many rooms are like that.

IME, so nothing scientific about it, in/on ceiling are more proper as they fire from above. But then one could compare it with the center channel positioning. Center channel under a flat panel is lower that LR so not ideal. I am a pretty picky individual, but the lower placement fools me every time I am not actually looking at the placement and thinking about it. If I focus all my energy (disregarding the soundtrack and the visuals), yes I can clearly pin point the issue. But in divided attention scenario of relaxed listening, this is not an issue.

Same thing is IME applicable to on-walls. They come from above, distinct from the bed layer and actually more convincing than the center "hack" as there are 4 (or more) of them so you can't actually visually focus on them. The important thing about Atmos is to have a convincing layer above the bed layer, which IMO will more depend on competent speakers than the placement, provided that on walls are properly placed. Having both would be best, but not that common.

 

[krabapple]

First Dolby is recommending placement in rectangular rooms. Also, ideal placement of all bed speakers is equal distance to MLP. Not many rooms are like that.

Distance, to a degree, can be 'equalized' using modern AVRs.

IME, so nothing scientific about it, in/on ceiling are more proper as they fire from above. But then one could compare it with the center channel positioning. Center channel under a flat panel is lower that LR so not ideal. I am a pretty picky individual, but the lower placement fools me every time I am not actually looking at the placement and thinking about it. If I focus all my energy (disregarding the soundtrack and the visuals), yes I can clearly pin point the issue. But in divided attention scenario of relaxed listening, this is not an issue.

Is your lowered center speaker firing straight forward or do you angle it up to fire at your head?

IIRC you are using 'elevation' speakers as heights? e.g.

 

[Oddball]

Atmos speakers fire above my head as they should. Dispersion at that distance fires some at my head as well. But unlike the example you posted, my Atmos can be tilted horizontaly and vertically to achieve the angle that sounds the best, which was tuned to my preference and irregular room.