Author Topic: Taking the "reflection" route on Dolby Atmos...  (Read 82345 times)

Offline desray

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Taking the "reflection" route on Dolby Atmos...
« on: February 16, 2015, 17:46 »
Discrete vs Diffused sound stage
For those who have been following my Dolby Atmos upgrade path will come to realize that I favoured Dolby Atmos enabled speakers/module over the in-ceiling speakers. One of the most important factors, amongst other is the height of my ceiling which is about 2.5m (a typical HDB floor-to-ceiling height). At this height, a full-range bookshelf speakers can be rather “distinct” and too “localized” to my taste. Atmos is all about “atmos-pheric” sound field that envelope and wraps you around within an audio “bubble”. In a cinema screening hall, if you looked above you, we are looking easily at a ceiling height of nearly 15m! That’s a huge difference in terms of floor-to-ceiling ratio. A full range speakers hanging above the truss in a typical cinema hall will cast a wider and more diffused sound onto the audiences down below as a result of the tall height. Thus in order to simulate that cinematic effect in a Dolby Atmos compliant theatre setting, Dolby Atmos enabled speakers/modules may be a better choice. For the record, I would still encourage members to opt for the ceiling speaker setup wherever possible. If you prefer a more “discrete” over “diffused” sound stage, then in-ceiling speakers or hanging a full range bookshelf speakers is still the best way to experience it. For me, I preferred a “diffused” sound stage and there is nothing wrong with that (YMMV). Of course, there are others who simply do not have a choice to install an in-ceiling speakers, be it for aesthetic or spouse acceptance factor which make it less appealing.

Benefits of a Dolby Atmos enabled speaker setup
So what are some of the benefits of going the “reflection” route? Well, here are some I can think of…

a)   No drilling and messy cabling
b)   Ease and flexibility of setting up
c)   Freedom to move your MLP around – you are not “fixed” to one particular seating arrangement/position
d)   More aesthetically pleasing, hence higher WAF whilst still able to enjoy the fruits of Dolby Atmos
e)   More realistic sound that simulates a cinema hall
f)   Covers a wider area of “sweet-spot” – some may not agree with me on this
g)   A more open and naturally sounding sound stage for playback of concert/music with Dolby Surround Upmixer (DSU) engaged


Can I just use an existing pair of bookshelf or satellite speakers to reflect sound?
Well, in the past, I would say “yes”. But now, I’m afraid this is not true. For what it’s worth, there is indeed some “magic” been done at a specific crossover points for a Dolby Atmos certified speakers to work properly. Granted! There are a few so-called Dolby Atmos certified enabled speakers/modules in the market that simply does not deliver what it promise – case in point, the pathetic attempt by Onkyo for the model, SKH-410 which use a 3” paper cone and even the Definitive Technology D60 Dolby Atmos elevation modules which cost $400+ per pair! Just when I am about to go on the drastic route of getting the speakers to be mounted on the ceiling, I managed to T-loan a set of KEF Reference series Dolby Atmos enabled speaker modules (model R50) for a home trial. I thought WTH, just give it another shot at it! To be frank, I am very sceptical about the KEF R50 ever since my less than favourable experience with both Onkyo and Def Tech Dolby Atmos speaker modules.

KEF R50 Atmos enabled speaker modules

I only T-loaned a pair for starters – it’s really heavy weighing at 4.5kg per speaker! The finish is of premium quality to say the least – befitting the Reference series. When I reached home, I decided to place the 2 KEF R50 speaker modules on top of my existing Surround Rear speakers (as per the recommendation set by Dolby in the White Papers). I performed one round of Audyssey calibration after making necessary changes to the “Amp Assign” settings. After completing the calibration, I playback the Amaze trailer and I was truly “amazed” by how much “perceived height information” I can hear from the trailer itself. For the first time, the bird circling above your head was able to be heard with such precision in directionality. Literally you can “hear” and “feel” the bird hovering in one circular motion. The heavy downpour within the tropical rain forest towards the end is also brilliantly executed. The next trailer was the fallen leaf trailer. When the leaf detached from of bud and the wind causing it to sway from the front to the side and then to the rear and to the front again, I am able to discern the precise “location” of the fallen leaf with my eyes closed. The directivity of the sound from the KEF R50 Atmos modules is simply astounding. My initial doubt on the performance of the KEF R50 was immediately removed just after these 2 trailers.

It is so good that I decided to get 2 pairs of KEF R50 from KEF (Singapore) – GP Acoustics P/L, the agent in Singapore. I have to admit that the price of these KEF Atmos modules do not come cheap. It is retailing at $1,600 per pair (MSRP), almost the price of a LS50! It’s a hard pill to swallow. I was fortunate to get some discount for 2 pairs from GP Acoustics.

My encounter with a well-built Atmos enabled speaker modules rekindled my faith with this “reflection” route and true enough, you can’t simply use an existing bookshelf or satellite speakers and hope to work. It doesn’t. For instance, there has been some “bumping” up with certain high frequency range in the likes of 5,000hz and a dip in 10,000hz to compensate for the “head-related transfer function” (HRTF) to create that “height” effect. The “magic” here is the use of Tangerine “waveguide” technology to increase the “directivity” and “intensity” of the sound to beam it onto the ceiling and bounce the “energy” back down to the MLP. A fairly similar technology employed by Pioneer’s Andrew Jones using the Concentric Driver Array (CDA) to achieve a more focused sound energy.

The key similarity between the 2 technologies lies with its integration of its bass driver with its tweeter moulded into one design, with the tweeter located right in the middle of the driver.

Still requires tweaking!
It appears that a little more tweaking still needs to be done though…particularly in the distance and how high you should place the speaker modules. My initial placement at the Surround Rear speakers was good and I am able to achieve a very “pronounced” height level details. However this is not so for the front speakers no matter how hard I tried. Then it dawned upon me that in Dolby’s whitepapers published for the Dolby Atmos enabled speakers/modules stated something about the minimum distance between the speakers and the MLP. To conform to that “requirement” – i.e. at least 3 ft between the front Dolby speakers in the front and the rear.

I moved my front speakers slightly towards my MLP until the distance reaches about 5 ft in the front and about 4 ft from the rear of my MLP. At the same time, I also used a taller speaker stand to “elevate” the height of the front speakers until it is slightly higher than the height of the wall. At the same time, I will also bump up the gain for the 2 pairs of Atmos speaker modules by about 3 - 4db to ensure the increased sound level can reach a certain mass for the sound wave to beam back to the MLP. With these little tweaks, I have managed to derive a very convincing “height” details from all 4 speaker modules.

Remarks

Desray, you make it sound like Dolby Atmos enabled speakers is the way to go? On the contrary that’s not the purpose of this post, rather I am trying to impress upon those having second thoughts and/or having the same mentality and perception that ALL Dolby Atmos enabled speakers are all the same…the fact is – it is not. With a good pair of Atmos modules and some tweaking in terms of the placement distance and height, you can get very good Atmos effect. Of course…and at times even better than ceiling speakers. The issue with Dolby Atmos speakers lies with the placement and it requires numerous run of trial and error before getting it right. If you are the type that wanted the “easy” way out, ceiling speakers or mounting speakers above you probably going to give you a faster efficacy of Atmos dosage, but if mounting speakers on the ceiling will probably create some tension with your loved ones or perhaps you simply cannot do it, then the reflection route is still a very do-able and viable solution for your Atmos “fix”. If done right, the end results will be equally on par if not better than speakers affixed to the ceiling. So do not dismiss the reflection route too quickly.
« Last Edit: October 11, 2015, 12:47 by desray »

Offline petetherock

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #1 on: February 16, 2015, 18:46 »
Well Mr Andrew Jones, who sells his own iteration of Atmos speakers agrees with you...
(the caveat is of course his vested interest... )
<a href="http://www.youtube.com/v/KBHDtPu9UJk&fs=1" target="_blank" class="new_win">http://www.youtube.com/v/KBHDtPu9UJk&fs=1</a>
Please post instead of sending a pm, so more can learn.

My gear:
https://peteswrite.blogspot.sg/2018/03/my-setup-32018.html

Offline desray

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #2 on: February 16, 2015, 20:19 »
Another noteworthy contender is Atlantic Technology (model: 44-DA)





I have called up 1877 (the so-called exclusive distributor for AT speakers here in Singapore) but their support can best be described as "lukewarm"...in the States, it is receiving some rave reviews...in fact more than KEF R50 due to the latter's presence is felt more in Asia like HK and mainland China.


Hopefully when I call them again, they will allow me to do a T-loan so that I can do a review on the 44-DA.

Offline sq13z

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #3 on: February 16, 2015, 21:42 »
Desray, do you know if the reflection will work for VOG by putting the a R50 or similar speaker on the center channel?

Offline desray

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #4 on: February 16, 2015, 22:50 »

Desray, do you know if the reflection will work for VOG by putting the a R50 or similar speaker on the center channel?

Nope. That's not gonna work for a VOG channel in Auro 3D implementation.


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Offline badbad2000

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #5 on: April 07, 2015, 10:33 »
Hi Desray,  do you know any alternative than KEF?  R50 is quite expensive.  Have you try out the  Atlantic Technology yet?

Offline wizardofoz

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #6 on: April 07, 2015, 11:27 »
Dual Concentric drivers or Coaxial drivers are most frequently used in car speakers and are cheap to buy with a small enclosure so this could be simulated by placing the enclosure (often with a sloping front) on top of your existing fronts and perhaps if you have stand mounted bookshelf surrounds on top of those too.


The other way might be to use them off a bracket facing up on the wall or in fact their own stand (DIY even)


I use something similar under my non speaker fitted Panny 65" Plasma that has built in amps. Using a Polk Audio coaxial 6.5" driver. This works very well for the TV sound. When/If I go to Atmos this is likely the way I will be doing at...as my fronts are open baffles this creates another challenge but I doubt I'll be doing anything before this time next year in the 5/7.1/2.X arena.


« Last Edit: April 07, 2015, 23:23 by wizardofoz »
I have a pile of stuff that pushes out squiggly waveforms from smaller squiggly waveforms that sometimes come from 1's and 0's.
It's wonderful to behold as long as you don't let the magic smoke out.

Life is short! Enjoy the music while it plays, when it stops, there might be a chair for you...or  maybe not.

Offline Doggie Howser

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #7 on: April 07, 2015, 12:28 »
I think the crossovers in the Atmos enabled speakers take into account the phase changes when sound is reflected - which standard speakers don't account for. :) Had a refresh of this during one of the study mates sessions I was helping out with.

End of Line - Derezzed

Offline desray

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #8 on: April 07, 2015, 16:33 »
Hi Desray,  do you know any alternative than KEF?  R50 is quite expensive.  Have you try out the  Atlantic Technology yet?
I haven't have the opportunity to do a review in that as the local distributor (1877) did not get back to me... But I believe it is one of the better ones out there.

Sent from my Nexus 6


Offline desray

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #9 on: April 07, 2015, 16:42 »
I think the crossovers in the Atmos enabled speakers take into account the phase changes when sound is reflected - which standard speakers don't account for. :) Had a refresh of this during one of the study mates sessions I was helping out with.
Yes... That's correct. Certain set of frequency will be altered to create that height levels.

Sent from my Nexus 6


Offline badbad2000

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #10 on: April 07, 2015, 17:01 »
So the r50 works very well? i read if only 1 pair result less convincing

Offline desray

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #11 on: April 07, 2015, 17:12 »
So the r50 works very well? i read if only 1 pair result less convincing
Not true... I have played with one pair before I decided to go for another pair. If placement is correct,  it can be very convincing.

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Offline badbad2000

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #12 on: April 07, 2015, 17:28 »
Can you illustrate more between the result of 1 pair vs 2 pairs?

Offline desray

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Re: Taking the "reflection" route on Dolby Atmos...
« Reply #13 on: April 07, 2015, 20:02 »
Can you illustrate more between the result of 1 pair vs 2 pairs?

Its hard to "quantify" and illustrate...all I can say is if the placement is correct, you will the "sensation" of sound coming from "above" you. The question is why did I get another pair of KEF R50, it is because I have been convinced that it really work! Hence my decision to get the second pair. Once again, it depends of the movie material that you are playing to justify that 2 pairs of KEF R50 worked...for instance, if there is a scene where a fighter jet do a fly-by from front to rear or vice versa, that's where 2 pairs of KEF R50 will take advantage to provide you with a more seamless sound field to simulate the action on the screen.

For ambience, just 1 pair of KEF R50 will be more than enough to provide you with the "height" elements...for instance in a jungle, raining scenes etc...

Offline badbad2000

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Re: Taking the &quot;reflection&quot; route on Dolby Atmos...
« Reply #14 on: April 07, 2015, 20:09 »
Thanks for the sharing. I will wait for the 44da come in demo before decide.