Speaker placement for HT: HOW FAR APART for separation & good imaging?

[Wechnivag]

What is the separation distance between the LR speakers planned currently? 8ft?

What is the perpendicular distance from MLP to the plane of the LR speakers?

From the dolby studio guide, you can see that for a given angle, the horizontal separation of the atmos channels increases with the height of the ceiling.

Are you side and back surrounds elevated, as the diagram is showing elevated. This means the angular separation from the side surround to tops is reduced, which pushes the angle towards 55deg of the (45-55deg ) range.

The 7 ft apart vs 4 ft apart. Personally i feel 4ft is very narrow, if you have a wide sofa the outer seats may even be outside of the atmos, which is a nono.

If you feel 7ft is too wide, just go with 6ft.

Have you also seen the Trinnov layout guide?

Trinnov_Loudspeaker_Position_Guide_2020.pdf

Perhaps because Trinnov usually deals with high seat count HT, they advocate even wider horizontal spacing of the Tops, at the 45deg elevation range, vs Atmos studio / HT guru at 55deg elevation.

The placement is affected by the height of the room.

Placing top speakers more ‘inboard’ that the outer seats is a NONO.

With trinnov, the tops end up as wide apart as the mains, so ~8ft in your case.

So all that considered, i think 6-7 ft is a good bet.

One final thing is are you using in-ceiling speaker, or mounting a bookshelf on a bracket. If the latter, make sure you calculate the angles to the Tw position of the the speaker on bracket, it will be up to 20 cm lower than the ceiling level.

[Wind]

Trinnov has this 3d remapping feature and it does the phantom speaker positioning wonderfully.

For my case, in order to experience DTSX and Auro3D, I sacrifices the Atmos layout. So I position my top middle a bit to the front of where I’m sitting, just like only having an Atmos .4 layout rather than an actual .6 layout, using the 3D remapping feature, my top middle becomes the top front, my rear height remains as top rear, and together both creates a phantom top middle.

I can show you if you be interested to drop by my place @Lampsy

[Wind]

Using your own pic as illustration, the red colours indicate the phantom speaker creates using 3D remapping.

[Lampsy]

My FL & FR - originally I planned to have them both 9 feet apart, LCR all three speakers 9 feet from MLP too, so basically LCR equidistant from MLP, 60° separation. My LCR bookshelfspeakers have a measured 30°on-axis performance rating (Audioholics). So I planned to toe them in towards the MLP.

My Floor to ceiling height is 270cm, planning to have a 15cm deep false ceiling, 4 in-ceiling speakers with custom 1 cubic feet wooden enclosure for each, so in-ceiling speakers to floor distance is 255cm (about 8.4ft).

I do plan to install the side & rear surrounds slightly higher than the listening ear level (1m)…maybe tweeter of side & rear surrounds at about 127.5cm (halfway pt of floor to ceiling distance).

My room is 5.1m x 4.8m btw.

[Lampsy]

Would love to give your HT a visit man, will DM you once i settle down with my reno stuff, busy currently finalizing things with ID.

[Wechnivag]

Very nice.

The main consideration for in ceiling speakers speakers is they fire straight downward.

Any way to aim them towards MLP?

Aiming to MLP is actually very important, the most important consideration for the atmos placement…

[Lampsy]

I will be using the RSL CG34E MKII in-ceiling speakers, they have 15° angled baffle . They are quite slim too depth wise.

[Wechnivag]

then another reason to keep them close together than further apart, all other factors being equal. To reduce the off axis angle to the MLP.

is the reason for 15cm deep ceiling purely for the wooden enclosure for the ceiling speakers?

i’m not too familiar with this model, but if they are designed for in ceiling with no cabinet, basically IB, putting them in a box (much smaller volume than IB) will tend to result in a very peaky bass response. Nothing that the Trinnov EQ can’t handle, but using them in-ceiling is not necessarily a bad thing?

[Lampsy]

Yes, the 15cm deep false ceiling is for the wooden enclosure. It is an infinite baffle design, but from what i have read a speaker enclosure/backbox is recommended. The manufacturer recommends a 1 cubic feet volume enclosure.

[Whitesox]

@Wechnivag

8ft?

Which one do you prefer top down approach or bounce back approach for Atmos effect?

[Wechnivag]

Hard to compare. The only reflection atmos, and also the first time I experienced proper atmos was at Desray. We all know that is very well done.

In ceiling, front heights, tops with various positions all have different pros and cons. Aiming the atmos at MLP is a must.

I’m on the same page currently with the elevation angles that we talked about in this thread. That’s where I will place my atmos speakers.

[petetherock]

I’m late to this, but just sharing some personal points:
Don’t get too hung up over the install, there is some latitude… there are whole forums / chats where people are up in arms over this, but there was a pro guy who said it’s fine to be a little off
Having said that my suggestions are

• use a laser point and a set square to get it right, others have said the angle matters more, and also the equal distance apart with enough spread to the front and back to get it right
• use the levels of volume for finer adjustments, it’s ok to do so
• tilting speakers like those you specced are a good idea

Good insulation, and bass management make a bigger difference than minor angles. Bro Gavin also has a good build thread…

I’m not done much since bro Bryan helped me, but pm me if you wish to listen to mine, which is out West.
Cheers