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Acoustics for Immersive Audio

11K views 65 replies 31 participants last post by  Mfusick 
#1 · (Edited)


Anthony Grimani, CEO of MSR Acoustics, talks about immersive-sound systems from an acoustician's perspective, including speaker placement, frequency response, and dispersion as well as the acoustic character of the room. He also discusses rooms of different size, points out the importance of so-called "wide" speakers in front, addresses the spousal-acceptance factor of so many speakers, shows us several of his recent home-theater projects that include Dolby Atmos, answers chat-room questions, and more.



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#3 · (Edited)
Wow thanks Scott for having Anthony as a guest. I have been encouraged that my layout in my home theater is good moving forward for Atmos. I had some concerns about how far back my back surround channels were but with the opinions that Anthony expressed my rear surrounds are perfectly placed. I was going to move them but will leave them alone now. Whew, less work. I have hung my ceiling speakers in line with my front left and right speakers which was one of his opinions that made for a better experience with Atmos. I have hung four overhead speakers. There is a pair just in front of my seating position and a pair just behind. Even though I do not have a Atmos processor I am getting my speakers placed for when I do. I am aiming to have a 9.x.4 system. I like the idea of wides and have them in the room now. They are being utilized with my DTS neo:x playback. They add a lot to the sound field so I would like to eventually purchase a system that will use them.

Going Atmos is turning out to be easier than I thought due to how I had laid out my speakers when first building the theater room. I don't have to make a lot of changes according to the opinions Anthony expressed on what makes a good layout for immersive sound. His ideas and mine mesh when it comes to getting my room ready for a future purchase of a Atmos processor.
 
#4 ·
Oh, about the remixing for home theaters. What a waste of time. I agree that the theater mix should be used. If you do any remix maybe do one for DTS neo:x until Atmos gets more established? I listened to Dredd last night in Neo:x and was pretty impressed. Can't wait to move on to Atmos.
 
#24 ·
I would like to publicly apologize to any film mixer that I may have upset with the quoted remark below. I gave it in the spirit of them having to sit down and mix a film again. I was thinking perhaps a mixer might be upset that they had to do it over for a home release. I am now aware I was out of line in thinking this would be the case. My mention of Dredd being mixed for the home in Neo:X 11.1 is acknowledgment of being grateful for this remixing and my acceptance of them. I also hope there are many more remixes of this sort that have gone unannounced but exist on many Blurry releases. If they do exist I hope the mixing into neo:x will continue. My listening to movies in my home theater make me suspect that perhaps such past mixes may be the case. If it is, the hard work and dedication of a mixer was fun to experience and in that moment made their rework time worth it.

To Filmmixer I acknowledge your talent and expertise. I could never do what you do. (would love to though) I am glad you are there doing what you do, and so well. To you I personally make this apology.
 
#6 · (Edited)
I have listened to this cast yet but a few days ago listened to a dealer webinar by Dolby and Pioneer (Anthony Jones) on Atmos for the home. What I took out of this was that Atmos speakers should be added in pairs, two up firing in the front and two up firing in the rear, or two pairs, preferably 4 pairs, in the ceiling, that no side or front or rear wall acoustical changes need be made to accommodate Atmos, that side surround speakers should not be mounted close to the ceiling but no more than 1.5 up the side walls in order to have no leakage from the sides to the Atmos ceiling whether bounce or direct, that if one only had 7 ft in ceiling height, bounce would be better, at least 3 feet (probably 4) should be between the listener and the ceiling speakers, and the ceiling speakers should be placed in line with the front LRs. I hope I remember all of this correctly. Regarding the ceiling bounce area for the up firings most anything would work well except for absorptive acoustical tiles which would work but not ideally and in such a case replacement with cork ceiling panels in the bounce area should be considered. Iif your side surround are mounted high, leakage in mu opinion could be adequately addressed by diffusion panels mounted on the ceiling in front of the sides.
 
#7 · (Edited)
Anthony's comments on how important the wides are echo what Audyssey found in their basic psycho acoustic research, http://www.audyssey.com/technologies/dsx/faq , makes me wonder why Dolby decided for DSU to not extract info to wides.....I hope Dolby re-considers their algorithm for DSU (Dolby Surround up-mixing), as my real world experience of nearly 2 years with wides "echos" what Anthony states, unless Dolby found there are patents that DTS/Audyssey has that keeps them from doing that (they don't want to pay royalties to competition).....That's a Q I'd like to have Dolby asked and answered in a future podcast, why DSU does not feed signal info to wides.
Yes - I realize for a Atmos feed if wides are present wides will be fed a signal but not for upmixing done via DSU, there had gotta be some Intellectual Property issue. 


Chart from Denon product:
 
#9 ·
My set up is 11.2, with high front speakers, rear speakers, presence side speakers, processed by the CXA Yamaha 5000, amplified by parasound. I should place two pairs of ceiling speakers, but doesn't have a processor wih enough channels. I don't like the idea of changing my lay-out, what I've done before. And besides I'm not sure If dolby atmos will become standard. Next year, most probably, we,ll have dts uhd. I do believe object search is the answer, but it needs to be mature. In this scenario the best option is wait.
 
#11 · (Edited)
Best laugh for me was when Anthony referred jokingly to Scott as the master exaggerator.

Of particular note was that often Anthony's preference were at a difference from the Dolby gospel as to the distance between the back channel speakers, Anthony preferring relatively close placement to change the angles from the Dolby recommended. Anthony is consistent with the early days of THX where close placement of the two rear channels was recommended and that ceiling speakers should be more towards the length center line of the room rather than lined up with the LRs especially when the LRs are widely spaced.

I find it very enlightening that Anthony said we are experimenting now. To me that screams wait a bit even though Anthony says we are getting pretty good results now in HTs for what the director etc intended.

Absent was the need for timbre matching of the ceiling speakers to the rest of the system. To me, this will be the biggest failing of home installations where timbre matching will just be ignored by most.
 
#12 ·
Scott, great show again with Anthony Grimani. You really need to have a 2-3hr long show whenever he is on, or at least book him back to back… to back.
I really want to hear about his Grimani system. To me it looks like a home theater system and not a 2 channel system in anyway. I figured his system was a room layout system not a speaker system.
 
#41 · (Edited)
:eek:Yes I 110% agree. I've gone to a lot of trouble with pro testing equipment and room treatment and trial and error to achieve a reasonably flat room response, and to have a system that can hit commercial theater SPLs and symphony hall SPLs (symphony not loud? try Mahler or Berlioz with the number of players they ask for)

For those that care there's no reason to mess with it.

For those that don't know any better or have other priorities...they're going to be constantly "remixing" content anyway by continually tweaking with the bass and treble or EQ controls, each of the kids will re-mix it there way, dad another, mom another. One speaker will be on the very reflective mantle (or is it better on the hearth, leave it there, we'll have to move it when the kids come over though), the other under the flower stand firing over carpet (no put it on top of the niknak cabinet behind the flowers but next week we'll put the flowers there so we'll change it next week) ....you can't guess what people will have in their living room, there is no "typical" so what difference does it make? Many family living rooms or family rooms change every other week?!?! Stop messing with it, it can't be fixed.

Cheers,
 
#15 ·
I enjoyed the show. It seems there is more than one way to implement immersive sound. And a lot of it is "it depends on the room" and getting the right balance of absorption and diffusions as it relates to a convincing surround field.

I look forward to hearing more about the various ways that immersive sound is implemented. It will be very interesting to see how this all shakes out say a year from now. That will most likely be when I pull the trigger if I do at all.

I especially loved his comments on the importance of wide speakers and how they are more important to filling the holes in the sound field than the ceiling speakers. It has me thinking hard about my room and what would yield the best results........and it may not be ceiling speakers at all.
 
#17 · (Edited)
What do we learn from all that has been presented so far? Dolby is really pushing Atmos. it is pushing it for the masses and that means up firing front and rear Atmos enabled speakers.

What is needed and in what order? A really good center channel and one much better than the Atmos targeted general consumer already has. wide dispersion LCRs (wide horizontal, narrow vertical). some wall treatment to pick up first reflections and bass trapping (not discussed but this is classic standard acoustical treatment). front side wall speakers aimed at the listeners to fill in the discontinuity present in classic 5.1 or 7.1 systems. Finally and only them ceiling speakers, at least 2 pairs and probably 3 or 4 pairs.
 
#18 · (Edited)
Scott, I enjoyed 100%, thanks.

Because I have all in-ceiling speakers, Atmos or a 3D sound is not available to me. It would be a waste of money.

I was extremely happy to hear Anthony talk about the benefits of using Wides.

I had talked to Chris of Audyssey a few years back about whether Wides would be of any use to my in-ceiling system. Chris thought it would not benefit me that much.

I went ahead and installed hoping for some noticeable difference in sound.

I installed SpeakerCraft's Time5's which pulled down out of the ceiling and turn to the exact position that is needed. They were installed 60 degrees from the center speaker.



Other than having a fantastic sub, the Wides were the greatest improvement to my surround sound.

It is as Anthony said: The front stage sound literally surrounds me. It fills in both on my left and right. I feel engulfed when watching a good Blu-ray.

If I hadn't installed Wides, I would be seriously considering what would it take to change over to Atmos or any 3D system. But because Wides are there, I don't feel too left out and happy with what I have.


m
 
#21 ·
Always learn so much when he is on your show, by far the most open and willing guest you have that really educates the masses. I would love an hour or even two hour show just on him showing theaters hes worked on and go over the break downs again like he did towards the end of this show. :)
 
#22 ·
On the wide speakers, I have installed them too. What a great sound improvement they make. Pans from front to back or reverse are so much smoother. Before I could detect a jump from front screen to surrounds. The phantom imaging was not good. Because I like the contribution they make to the sound I will be waiting for a Atmos system that will use them. Basically I am wanting a 9.x.4 system. I would buy the Marantz 7702 preamp if I knew it would do the 9.x.4 processing. I have the power amps installed and ready to go.
 
#35 ·
Great interview, it really fills in a lot of blanks that came to mind from Wilfried's Auro interview that didn't get answered for me in the use of dispersive vs more focused speakers. Great examples, thanks Anthony.

I don't seem to miss the front sides at all in my system with front to rear pans, what tends to happen though is that the sound will shift towards the top as it gets to the listening position and then shift back down, almost as though I have ceiling speakers but I don't, I could experiment with rear speaker placement to see if I can clean this up but since I seem to have strong side imaging already I think I'd try adding front height speakers first, they can always be moved to the front side position if that turns out better. I'd still be eager to hear the reply to the question below though.



Great question, although I think I might just try both and see what sounds best for my room.
 
#26 ·
what an awesome episode,i love this guy! any how
Just a curious question and i probably know the answer to this already.
how about buying Pro cinema Speakers like JBL OR Klipsch etc and install them in our basement that some of us have room for them will that fix most issues?. Some of the folks here does have these speakers setup :)
 
#27 ·
I really respect Anthony. This definitely places a brand new emphasis on having a 9.x.2 for my future sytsem.

So I will wait for receivers that can do this (have wides).

I'll be using separates so I only need the receiver to include Wides as part of the pre-out architecture. Such doesn't exist for modest price yet, right?
 
#28 ·
I really respect Anthony. This definitely places a brand new emphasis on having a 9.x.2 for my future sytsem.

So I will wait for receivers that can do this (have wides).

I'll be using separates so I only need the receiver to include Wides as part of the pre-out architecture. Such doesn't exist for modest price yet, right?
Any receiver that does 11 channels can do a 9.1.2 configuration.
 
#43 · (Edited)
I just had a single pair of ceiling speakers installed to expand to a 9.1.2 system. I had originally planned to add two pairs of ceiling speakers for height; two in front, two at listening position depth. There are two main reasons I chose a single pair of height speakers:

1) My room is approx 15 ft deep from screen to back wall. After careful consideration, I decided that given the rather shallow depth of my room and the single plane of seats, 2 speakers approx 5 ft in front of the listening position and set at about 30degrees outset should be ideal. The result was that the "black-hole" left by the absence of the front height channels does not seem to exist with my set up.

2) Any Pre/Pro/AVR within reason is going to make you give up the Front Wide speakers to get the second set of height channels. DONT DO THIS!!! The single best addition to my setup was my experimentation with the Front Wide channels. Game changer. My feelings seem to be affirmed by Mr. Giamani's feelings - once you go Front Wide you don't NOT go Front Wide.

3) sorry. I can add a second pair of heights as the AV gear evolves.

My setup does defy Dolby's proposed setup, but their room models are typically square or close to square which I think is uncommon and limits perspective in the minds of amateur installers.

-Dave
 
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