Why do cinema and music Dolby Atmos layouts differ?

[sarumbear]

According to very detailed Dolby Atmos speaker layout guides a 7.1.4 layout shows the ceiling speakers as aligned with the LR and are inside the side surround speakers.

However, Dolby's advice on speaker layout for a music recording studio is pretty vague add "overhead speakers mounted on the ceiling of your studio." The following picture of a studio is on their Atmos game music page, which shows the ceiling speakers outside the mains.

This layout is the same on almost every recording studio I have seen so far.

Does anyone know why there a difference?

Thank you.

 

[charleski]

maybe it has something to do with using 6 height speakers instead of 4?

 

[sarumbear]

maybe it has something to do with using 6 height speakers instead of 4?

Here is their 7.1.6 layout from the same page that I linked. There isn't even the curve that exists on the recording studios.

 

[LukeD]

I watched a youtube video a few days ago that highlighted that the Atmos specifications for the home theatre are vague and missing information compared with the pdf manuals for setting up a studio or cinema. Could that be the difference?

Basically the video recommended using the recommended studio set up (which has tolerances on all speaker angles etc) rather than the "home" set up guidelines.

 

[-Matt-]

I think it is likely that it is the angle that is important.

So, depending upon ceiling height (and the room length/distance to LCR) the ceiling speakers could either be inside or outside of the LRs.

 

[sarumbear]

I watched a youtube video a few days ago that highlighted that the Atmos specifications for the home theatre are vague and missing information compared with the pdf manuals for setting up a studio or cinema. Could that be the difference?

The issue is the exact opposite. The Atmos for home theatre is as concise and elaborate as it gets. Haven't you seen the link I posted from Dolby. It covers every possible speaker layout scenario.

Basically the video recommended using the recommended studio set up (which has tolerances on all speaker angles etc) rather than the "home" set up guidelines.

Where is that "recommended studio set up". I couldn't find it.

 

[sarumbear]

I think it is likely that it is the angle that is important.

So, depending upon ceiling height (and the room length/distance to LCR) the ceiling speakers could either be inside or outside of the LRs.

I was hoping an authoritative answer. Besides, even in large cinemas the ceiling speakers are not angled they fire directly below.

 

[-Matt-]

Incorrect

 

[LukeD]

The issue is the exact opposite. The Atmos for home theatre is as concise and elaborate as it gets. Haven't you seen the link I posted from Dolby. It covers every possible speaker layout scenario.


Where is that "recommended studio set up". I couldn't find it.

I had a flick through some of the layouts in the link you provided. Didn't think they were very detailed w.r.t. angles between all the speakers.

This is the youtube video:

Ignore the clickbait title, I thought it had some decent information in it.

In the description of the video he links to a few dolby documents.

 

[sarumbear]

Incorrect

what is?

 

[sarumbear]

I had a flick through some of the layouts in the link you provided. Didn't think they were very detailed w.r.t. angles between all the speakers.

No angles? So what are those numbers then?

 

[-Matt-]

what is?

You asked for an authoritative answer - I gave one.

As is your typical style (either flippant or rude) I gave no justification or explanation.

 

[LukeD]

No angles? So what are those numbers then?

View attachment 246632

Only for the surrounds. Not the heights which is what you asked about right? Or did I misinterpret your OP? If so, sorry.

 

[Dj7675]

According to very detailed Dolby Atmos speaker layout guides a 7.1.4 layout shows the ceiling speakers as aligned with the LR and are inside the side surround speakers.

View attachment 246629

However, Dolby's advice on speaker layout for a music recording studio is pretty vague add "overhead speakers mounted on the ceiling of your studio." The following picture of a studio is on their Atmos game music page, which shows the ceiling speakers outside the mains.

This layout is the same on almost every recording studio I have seen so far.

Does anyone know why there a difference?

Thank you.

Attached is the pdf for the studio layout guides. I think they are quite helpful with a room layout. The Dolby home layout does show the tops aligning with the L/R main speakers. However I think that’s is more a function of the room dimension ratio than anything. When looking at the Dolby home guide it could be easy to get the atmos speakers very wide on ceiling which in some rooms could get poor separation from the surround bed layer speaker. Of course the studio guidlines aren’t for very many seats so you have to take that into account. I think the two best references are the studio setup guidlines and also the Trinnov Speaker guide LINK Trinnov layout is really nicely done and attempts take into account room shape, surround formats, and seating layout.

 

[sarumbear]

You asked for an authoritative answer - I gave one.

The word authoritative means "able to be trusted as being accurate or true." How do I know that you are such a person if you do not backup your words? I don't know you in person and your profile is blank.

 

[voodooless]

There is also this one regarding angles of the tops:

 

[-Matt-]

There is also this...
https://www.dolby.com/siteassets/te...atmos-installation-guidelines-121318_r3.1.pdf

 

[sarumbear]

Attached is the pdf for the studio layout guides. I think they are quite helpful with a room layout. The Dolby home layout does show the tops aligning with the L/R main speakers. However I think that’s is more a function of the room dimension ratio than anything. When looking at the Dolby home guide it could be easy to get the atmos speakers very wide on ceiling which in some rooms could get poor separation from the surround bed layer speaker. Of course the studio guidlines aren’t for very many seats so you have to take that into account. I think the two best references are the studio setup guidlines and also the Trinnov Speaker guide LINK Trinnov layout is really nicely done and attempts take into account room shape, surround formats, and seating layout.

Thank you for this. It is exactly what I was looking for.

Though I am still non-the-wiser why studios locate the ceiling speakers inside the surrounds? The guide shows them to be inside the surrounds not aligned to them. However, reading the Trinnov's guide I gather that ceiling speaker placement is a compromise between Atmos, DTS-X & Auro 3D and studios do not follow Atmos guide to the tee.

 

[Dj7675]

Thank you for this. It is exactly what I was looking for.

Though I am still non-the-wiser why studios locate the ceiling speakers inside the surrounds? The guide shows them to be inside the surrounds not aligned to them. However, reading the Trinnov's guide I gather that ceiling speaker placement is a compromise between Atmos, DTS-X & Auro 3D and studios do not follow Atmos guide to the tee.

View attachment 246639 View attachment 246640 View attachment 246641

You will notice that for most installs, surrounds are and should be slightly above ear level (In room they must clear heads and seat backs). In order to maintain angles of separation the ceiling speakers have get further away from those surrounds so they get pushed higher on the ceiling/more on top of the listener. This of course has limits and compromises too as if they get too far from the surrounds, then for example a top left speaker may not be coming from the left from the listeners perspective. You would never want a "left" speaker to not come from the left from any listening position you care about... that is where the Trinnov guide is helpful IMO. The biggest decision you have to make IMO is how many seats to you want to optimize for... and plan accordingly.
I don't think you need to consider how the atmos speakers line up to the L/R or the surrounds. It is all about taking the number of atmos speakers you are gonig to use and creating the height "bubble" around the listeners. They may or may not line up with the L/R or the surrounds...

 

[sarumbear]

You will notice that for most installs, surrounds are and should be slightly above ear level (In room they must clear heads and seat backs). In order to maintain angles of separation the ceiling speakers have get further away from those surrounds so they get pushed higher on the ceiling/more on top of the listener.

I realise that, however, if you look at the pictures you will see that recording studios do the opposite, hence my post. Especially look at the the first picture on my post, the blue room. The height speakers are almost on top of the side surrounds. In your suggestion, which I agree and, which Dolby guides agree the height speakers should be nearer to the centre, hence increasing the angle between the surround and them.