Atmos height speakers - at the top of side walls

Rob.Screene

Active Member
Hi,
I am planning a Dolby Atmos upgrade. I am currently running a 5.2 system with two big SVS subs in a converted garage.

I currently have some floorstander Linn Keilidh speakers as L+R
I also have another pair of Linn Keilidh floorstanders mounted upside down on the side walls as SL+SR, suitably behind the three seats. The leap to using the the same for front and back was huge, as is the bass control and impact of good sized cabinets.

I have read that upward firing Atmos height speakers don't work well because only treble finds it's way to the ceiling and back.

A complication I have is that I have a soundproofed ceiling, with a bedroom above the dedicated room. It is resiliant channel floating ceiling with two layers of soundboard, and the floor above floated on rubber "top hats" and sealed.

At the moment I can listen at -14db (below reference level) and still have my daughter drift off to sleep in the bedroom above. As you can imagine, I don't want to put any holes or mount speakers on the ceiling.

I am looking in to mounting two height speakers at the left and right wall tops, around 10 degrees in front of the the three chairs as-per the Atmos 5.2.2 recommendation angles. I also luckily bi-wired the surround speakers, so can easily split those to off to feed the two height speakers.

I am not likely to add front height speakers, as I didn't pre-wire the room for those and the equipment rack is at the back. Plus I have bass traps in the top of the front wall corners.

I am considering the Elac Debut A4, XTZ S2 or KEF R50 atmos speakers. These range between about £250 and £600 a pair.

I have also seen SVS Elevation Prime on wall speakers. I guess Q Acoustics do some great value speakers that can be wall mounted, but I assume that these being ported mad not work well with corner loading between the ceiling and wall.

I guess I need them angled downwards, so if the XTZ or KEFs can be safely mounted on the walls downward firing then it could work well.

Any thoughts or experience appreciated.

regards,
Rob.
 
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gibbsy

Moderator
If you want to have speakers on Atmos duties mounted as high as possible on the wall then I certainly would not go to the added expense of using specialist modules. Angled downwards and towards the MLP then any small standmount would do the job perfectly well. KEF R50s work very well in their correct upward firing position but definately need a ceiling with a good flat reflective surface, they are not designed to work in an inverted position.

Using standmounts I would still cross them at 120 or even higher, bass isn't an issue as it is non directional and the subs will handle it well, even in a full x4 in ceiling layout.
 

avanzato

Active Member
I used some small PSB alphas high up on the side walls for a while.
It worked OK. Not quite as good as my in ceiling speakers but good enough.
 

gibbsy

Moderator
Plug the port completely and set the crossover to 180hz. Working and configured as Atmos, even with DSU or Neural:X the receiver will not be sending a full range of bass to the speakers. They will need to be set as small.
 

Rob.Screene

Active Member
I just ordered a pair of JBL Control 1 Pro's. I think the Pro's come with the nice and simple ball-joint wall mounting.

As they are only 1.8 Kg each, I may even put four wood screws up in to the double ceiling soundboard. I guess I can see what the dispersion sounds like for the three seats with them wall mounted first, depending on how far downwards I can angle them using the ball joint.

80Hz bass and maximum SPL: 108 dB continuous, 114 dB peak looks to comfortably exceed the above Atmos requirements.

Ref: https://www.jblpro.com/ProductAttachments/Control1Pro_brochure.pdf
 
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Rob.Screene

Active Member
Oh and £140 a pair price and matt black rubberised(?) finish fact that Phil Hinton uses them made the choice quite a simple one.

regards,
Rob.
 

gibbsy

Moderator
I just found this in the Atmos spec:

"If bass management is used, the surround loudspeakers frequency response (±3 dB) must extend to 90 Hz or lower. The crossover frequency should be set based on the capabilities of the surround loudspeakers, but must not be higher than 100 Hz."

Ref: https://www.dolby.com/us/en/technologies/dolby-atmos/dolby-atmos-specifications.pdf
That's for theatres, not in the home. Very few Atmos modules can go that low, my KEF R50s roll off Audyssey at 100hz, yet integrate into my system far better at 120hz.
 

mb3195

Distinguished Member
Oh and £140 a pair price and matt black rubberised(?) finish fact that Phil Hinton uses them made the choice quite a simple one.

regards,
Rob.
I've got 4 for sale in the classifieds for 110 or 2 for 60.....brand new although admittedly not the pro's
 

Rob.Screene

Active Member
In short, I now have 4 Atmos ceiling speakers hanging from the walls...

I tried the 4 JBL Control 1 Pro speakers hanging off the soundproof ceiling and the family noted that acoustic isolation to upstairs was noticeably compromised.

Probably the 4x 1.8Kg hanging off it pulling down on the resiliant channels, making them not resiliant at all, in addition to the 16 screws screwed in through the two layers of soundoard, plus having speakers up high near ceiling level.

I found a blacksmith on ebay supplying large black rolled steel shelf brackets. I bought 8 inch by 6 inch as I was limited in height by the door on the right.
Black Coated Galvanised 1" Fluted Heavy Duty Shelf Brackets 7 sizes available. | eBay

I then cut some timber to about 3.4 ft with diagonal ends to but up close to the coving but hang below the ceiling, definitely not touching it.

I also took the opportunity to move the ceiling speakers inwards a few inches as I had read that they should be a max of 75% of the room width apart. I.e a minimum of 12.5% away from the side walls.

I filled the small screwholes with acoustic sealant and put some spare Auralex acoustic foam squares in the inch gap between the top of the gallows wood and the ceiling.

This was to hide the white sealant where the screwholes had been, but also to dampen the first reflections from the back of the speakers from bouncing off the ceiling.

The result is better soundproofing once again and better ceiling soundstage.

(it's a dark cocoa brown wall and ceiling, so i had to use flash to photo them)
IMG_0044.JPG
IMG_0045.JPG


Rob.
 
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