The “Dolby Atmos Home Entertainment Studio Technical Guidelines” (Studio Guide) explains how to best place speakers for Dobly encoded audio playback. Link here

 

Like the Home Dolby speaker setup guides found on the Dolby website, the Studio Guide gives a range of angles for speaker positioning. However, the Studio Guide adds minimum, maximum and ideal angles.

 

The positioning of Overhead/Top speakers is described quite differently compared to the Home guide. They are not shown in line with the Front Left and Right speakers. Instead, The Studio guide has 3 drawings; what I’d describe as a plan, front and side view. These give angles and elevations, both of 45 degrees from the main listening position. Interestingly, the elevation angles change depending on the height of the ear level speakers. For every 2 degrees of elevation, the Top speakers move in towards the room center by 1 degree.

For example, if the side surrounds are 10 degrees horizontally above ear level, the Top speakers move in to the room 5 degrees. So instead of being 90 degrees apart (45 degrees either side of vertical), they become 80 degrees apart (40 degrees either side of vertical). This is described as both the minimum and ideal angle!

 

Some other points:

“All speakers should be angled both vertically and horizontally toward the mix position”.

With some in wall and in ceiling speakers, this may not be possible. In ceiling speakers that can't be angled may work better grouped more centrally over the listening position.

 

“Surround speakers of differing heights should follow a smooth line from the screen speakers through the acoustic center of the surround speakers”.

 

There’s lots more information in the pdf on speaker placement, layout widths and heights, room dimensions and specifications.

 

Cheers

Dave

 

Edited February 5, 20233 yr by cdave
Typo

for some reason ( Linux operating system maybe) i can never open that link. anyway the usual dolby guides are dumbed down for the general public.. they need to be carefull of copyright infringement of Auro 3D 30 degree height speakers haha. but at least dolby are letting some know the real placement.

You have probably seen it Dave but the home theatre gurus installer guy on YouTube has dissected this on a few occasions now. He absolutely supports this view / analysis of the guide re the width placement for atmos (ie they don't have to be in line with the mains). I think one thing to keep in mind is width of the room as well though. Mine is only 3.96m wide so my kef Eggs as Atmos work quite nicely 70cm in from the wall in line with my mains on stands as I'm not that far from them.. But then all my bed speakers are at 1.2m I guess, basically ear height. On second thoughts perhaps I should get a protractor. It might verify everything you said anyway 😄

Thanks usethe4c, HTG’s was the reason I found the pdf.

Each speaker I've moved to Dolby's Ideal angles the better it's sounded 🙂 and so the reason I posted. 

 

If your surrounds are ear height, the math is straight forward. For your room, if the ceiling height was 2.4m with in ceiling speakers:

Room width of 3.96m /2 = 1.98m for the room center (assuming that’s the median listening position).

MLP of 1.98m minus the distance in from the side walls for the Top speakers of .7m = 1.28m

Assuming a 2.4m ceiling height and ear height the same as your surrounds of 1.2m:  2.4m - 1.2m = 1.2m

For 45 degrees, the 2 distances of 1.28m and 1.2m would be the same. In this example the Top speakers would move in .08m for the minimum and ideal angle.

If your Top speakers are below the ceiling, you would take that distance off the ceiling height.

For angles other than 45 degrees, my math sucks so I use an online right angle triangle calculator 😉

Ywa

1 hour ago, cdave said:

Thanks usethe4c, HTG’s was the reason I found the pdf.

Each speaker I've moved to Dolby's Ideal angles the better it's sounded 🙂 and so the reason I posted. 

 

If your surrounds are ear height, the math is straight forward. For your room, if the ceiling height was 2.4m with in ceiling speakers:

Room width of 3.96m /2 = 1.98m for the room center (assuming that’s the median listening position).

MLP of 1.98m minus the distance in from the side walls for the Top speakers of .7m = 1.28m

Assuming a 2.4m ceiling height and ear height the same as your surrounds of 1.2m:  2.4m - 1.2m = 1.2m

For 45 degrees, the 2 distances of 1.28m and 1.2m would be the same. In this example the Top speakers would move in .08m for the minimum and ideal angle.

If your Top speakers are below the ceiling, you would take that distance off the ceiling height.

For angles other than 45 degrees, my math sucks so I use an online right angle triangle calculator 😉

Yeah right look at you on the ball on a Sunday evening ,😉

 

I did get out the Bosch laser measurer (essential cheap tool!) and did some basic percentage maths from the base Dolby guide at the time. The centre of each of the tweeters are just under 60cm from the wall but the driver is pointed at the MLP as well. The kef Eggs are satellite speakers 88db efficient on little stands with uni q drivers which makes them both quite angleable and nice with dispersion at 160 degrees. Cutoff is 80hz, with the ceiling re enforcement the receiver chose 80 too. The receiver measured 45 deg at front 55 at the back so within the range from front  to back

 

I agree the closer you get to standards with everything and careful with distances the better it sounds. Most members that wouldn't have thought about it here wouldn't believe the difference it makes really (neither would I before doing it) It just means your room correction has less to deal with. Bed layer changes for me made really good improvements ideas for which I got from HTG . I find the guy a bit of an over bearing evangelist sometimes though. I personally really enjoyed moving my side surrounds forward to 100 degrees. Cool change I thought which I got of a U.S acoustics website.

 

During the tao tai sequences in great wall I thought something was running around in my roof for atmos (I've had snakes before lol) so sounded like I got it reasonably right.  Will consider though.

 

Cheers

 

Steve

 

 

 

 

Edited February 5, 20233 yr by usethe4c