Dolby Atmos and DTS-X: How many channels are really enough?

[KeithL]

This one is sort of obvious.

[lrobertson]

I understand the content concern for speaker numbers and their actual benefit being highly dependent on the content. Is there anyone with any experience with Trinnov and the top tier Atmos movies say Matrix, John Wick or those types that has an opinion here? I’d also be curious about Atmos games and whether the concern for content in that regard is the same. Can those make use of all 128 object channels or do they have some sort of limiting factor that won’t allow proper playback if you say max out a RMC-1?

[lrobertson]

Keith if you let me apply my 40% off coupon to get all three 4-channel expansions with the RMC-1 I’d be happy to give your forum topic here the best non biased assessment I can as your layouts roll out haha. Until the RMC is out though I’d imagine you guys would be the best to offer speaker number suggestions based on room size and I guess in relation to top tier Atmos movies. 99% of people have to base this question on the theoretical myself included. I’d like to say a 17.1.10 would be a unbeatable layout but for all I know a blind test with 11.1.8 might be really similar. And like is being said I’d have to periodically make due with sub par movies until those top tier ones get churned out which I’d be ok with.

[Gary Cook]

As posted a few times, my friend's set up is 5.1.2 (using a Yamaha CX-A5100) in a smallish room and it is a big step up from the 5.1 he had previously using a 4 year old Onkyo (non Atmos/DTS-X) processor. We tried all formats up to 11.1.6 (using a Storm processor) and they really didn't add much compared to the 5.1.2.

I should also add that my observations so far are that streamed Atmos is redered over Dolby Digital+ (hence 5.1) not Dolby True HD 7.1.

Cheers
Gary

[lrobertson]

Small is a relative term. What dimensions do you think it was? When you ended up upmixing the storm what’s the word you would describe forgetting the fact it wasn’t discrete? Fuller? More immersive? I thought you said it sounded relatively good for not being discrete. I understand the benefits weren’t enough to justify adding 20k but what about 1-1.5k?

[AudioHTIT]

In my room I could actually imagine 11.2.6, but I’ll probably end up with 7.2.4 or possibly 9.1.6. I’m sure the answer depends on one’s room and the quality of the source. Actually the question isn’t obvious to me, do you want to know what we might do? Or are you continuing the discussion from the other thread about what differences might actually be heard as the speaker/channel count increases. So, practical or theoretical?

How about adding a poll with some common configurations? (up the the max the RMC-1 could support)

[davidl81]

I have 7.2.4 in my theater room that is appx 25x15 and I could see going 9.2.6, but I would assume the benefit would be pretty small. If I was building from scratch now I would most likely do it just because, but I don’t see any reason to upgrade to it.

[Gary Cook]

Oct 23, 2018 19:33:37 GMT -5 lrobertson said:

Small is a relative term. What dimensions do you think it was? When you ended up upmixing the storm what’s the word you would describe forgetting the fact it wasn’t discrete? Fuller? More immersive? I thought you said it sounded relatively good for not being discrete. I understand the benefits weren’t enough to justify adding 20k but what about 1-1.5k?

I really don't know what size it is, there are only 2 of them in the house, plus 2 small dogs. It's a bit longer than wider, so we found the best place for 2 ceiling speakers was along the room, not across like the recommended Dolby 5.1.2 lay out. With the lounge up against the rear wall and 3 metre high ceilings there's a lot of air space to fill and it's about 3 metres viewing distance to the 60" TV. It has base traps, W2W carpet, double layer curtains and 3 acoustic panels that look like paintings on the walls. Obviously we YPAO'd it, plus I ran an REW check to make sure.

We couldn't do 7, no room for rears, we tried overhead rears (wall mounted facing downwards) but combined with the ceiling speakers it just didn't work. When we located the rear speakers closer to the walls it gave some strange acoustics, with them along the room it sounded the best. We maybe could have used some more acoustic panels to get 4 locations to work but realistically it probably still wouldn't have been as clean as the 2. For clarification, each of the 2 ceiling speakers has 2 dual concentric Tannoy drivers, connected so that there are really 4 channels in use (ie; 5.1.4) just located in only 2 locations. So we call it 5.1.2 for simplicity.

Sitting on the lounge, just listening to the movie it was hard to pick the matrixing, upmixing, extrapolation etc required to get the additional channels (that weren't in the source). But get a bit closer to the speaker and listen to a moving sound effect it wasn't as seamless as straight Atmos. Which just moved smoothly between channels. In a bigger room I think it would be more noticeable from the seating positions. I relate it to the first time I heard Dolby Pro Logic, it sounds good but not quite "right". Plus both of us are hifi music nuts, so probably more critical of that than, say, a HT enthusiast.

The Yamaha CX-A5100 cost him $A2500 and an RMC-1 will be well over $A8k when we get it, judging by the XMC-1 prices here. So, despite my best efforts, an easy decision for him. Plus he will keep it for 3 to 4 years (same as his previous AVR's and processors), sell it and then buy what is up to date technically at the time. He can do that 4 maybe 5 times, be right up to date, and still not spent what 1 x RMC-1 would cost him.


Cheers
Gary

[lrobertson]

I enjoy stalking people on FPS games where you can’t respawn so it’s usually slow and methodical movement through multiple story building or outside. I could see benefit in how the Atmos games could really transform that type of virtual world. I could see more benefit in a higher channel count with this type of content than movies. As to how many channels really come down to speaker angles and is there any reason to have speakers with 45, 30, or 20 degree spread. Theoretically 20 is best for the content not meant to be localized but would anyone pick it out in a blind test. Content is a factor but Atmos games should always map objects to relevant speakers and that makes it a lot more interactive and accurate. Now I’m inclined to believe the top Atmos movies of all time would benefit but maybe those are even harder to tell a difference. I’m inclined to try 17.1.10 if it’s ever offered and if it felt like a mediocre step up from 11.1.8 I’d repurpose the speakers for a set up at my family’s cabin and go back to the 30 degree spread with 11.1.8. No loss and I get to actually know for myself the benefits. I say no loss but in reality the time spent breaking down and re setting up the room if I were to move to 17.1.10 and then potentially back would be a large loss of time and I value that.

[knucklehead]

I could add 2 speakers to my current 5.2 setup (And that is a big 'if'), and the 2070 Yamaha is probably up to the task. Seems easy enough to add two speakers on the overhead. I know my setup (5.2) is antiquated, but I seldom watch movies in surround sound, preferring the two channel sound, with subs of course.

[lrobertson]

Well if we want to be technical and tell everyone how much is enough for us ourselves then my answer would be two. That’s all I really need. I’m lucky to get one working speaker without crackling where I work. Now if the topic is more based off of maximizing Atmos as the forum doesn’t ask how many is enough for you then it’s less practicallity or your own room and imagining yourself stepping into rooms with different layouts and picking the one where moving up is indistinguishable or at least such a small improvement you couldn’t see spending a couple hundred in moving up. I talked about what I’d like to set up because I’d like to max out Atmos and find out that layout. If 7.1.4 is practically undetectable in an a/b with 11.1.8 that would definitely mean 7.1.4 was enough (with the 5 movies chosen as best Atmos of all time... haha I don’t want your movies Gary. I want you to be able to judge and make sure your v10 is running on all cylinders for grading your movie experience). It sounds like for a really small room that has a hard time fitting rear speakers in it there is not much benefit in attempting to squeeze more than say 5.1.2. I’ll go on the limb and say there is no benefit to DTS:X in any size room after say 7.1.4...

[Gary Cook]

Oct 23, 2018 22:39:36 GMT -5 lrobertson said:

Well if we want to be technical and tell everyone how much is enough for us ourselves then my answer would be two. That’s all I really need. I’m lucky to get one working speaker without crackling where I work. Now if the topic is more based off of maximizing Atmos as the forum doesn’t ask how many is enough for you then it’s less practicallity or your own room and imagining yourself stepping into rooms with different layouts and picking the one where moving up is indistinguishable or at least such a small improvement you couldn’t see spending a couple hundred in moving up. I talked about what I’d like to set up because I’d like to max out Atmos and find out that layout. If 7.1.4 is practically undetectable in an a/b with 11.1.8 that would definitely mean 7.1.4 was enough (with the 5 movies chosen as best Atmos of all time... haha I don’t want your movies Gary. I want you to be able to judge and make sure your v10 is running on all cylinders for grading your movie experience). It sounds like for a really small room that has a hard time fitting rear speakers in it there is not much benefit in attempting to squeeze more than say 5.1.2. I’ll go on the limb and say there is no benefit to DTS:X in any size room after say 7.1.4...

I get to play with this one, sometimes;


On the topic of DTS-X, it's no different to Atmos you can use the extrapolation, upmixing, matrixing, upscaling etc in the processor to expand it to however many channels/speakers the processor can support and/or you've got in you room.  Gladiator in 4K with DTS-X is awesome, especially the scenes in the Colosseum, the sound track completely surrounds and then falls down on top of you.   That's without any upscaling, matrixing, upmixing etc.


Cheers
Gary

[mgbpuff]

I think 7.1.4, which is what I presently have, is enough. However I planned my 13.5' x 21' non dedicated HT room for 7.1.6 and I have the extra TM speakers for when I can get a pre-pro that can support them. My room is too narrow for wides, but I could possibly use a height center as my center now is below the screen. Also I now have 2 pairs of SR and SL speakers in series (essentially a SR and SL array), so I suppose those could be discrete channel also, giving me a max of 9.1.7 in my present room.

[DYohn]

I currently run 5.1.2 and I am very happy.

[Casey Leedom]

DYohn, is your 5.1.2 system using Ceiling Reflectors for your 2 Height Channels? Just curious since that's probably the only way I could manage to do the same in my Living Room.

Casey

[DYohn]

Oct 24, 2018 11:26:19 GMT -5 Casey Leedom said:

DYohn, is your 5.1.2 system using Ceiling Reflectors for your 2 Height Channels? Just curious since that's probably the only way I could manage to do the same in my Living Room.

Casey

No I installed in-ceilings for the heights.

[Casey Leedom]

Ah. I think I may try the Ceiling Reflector stuff. Trying to run lines in my Apartment Living Room really isn't an option ...

Casey

[sahmen]

I do not think there's really any correct answer to the question "how many are enough"? That is because everyone's needs are different, and often evolving. Under my present circumstances, and the spaces available to me, I think 5.2.4 or 7.2.4 both work fine, and are enough... I really can't work with any options that involve higher numbers in speakers than these, but I can easily see how things might be different for others with bigger spaces and correspondingly bigger numbers in needs.

[bootman]

How many amps (channels) does Emotiva want to sell?

[405x5]

This ought to cover it