A Guide to Dolby Atmos in the Home - article discussion

AS suggested, spend a bit more on an external amp that is good with 2 channel music andd use it to powwr the front left and right speakers with. You van then reassign the internal amplification otherwise used to power the fronts to power the additional Atmos speakers with.

Emotiva make some very good external power amps, but there are also some excellent 2 channel integrated amplifiers out there that have something called HT Bypass. This alloes them to be used as a power amp in cionjunction with an AV receiver. Such amps are ordinarilly very good with 2 channel music sources due to their 2 channel intergrated associations. You would have to pay more for one of these integrated amps when compared to most 2 channel power amps though.
Thanks for your advice. Food for thought. I will have to discuss budget with my partner. The Emotiva may be out of range.
 
If budget is an issue then you are probably better off concentrating your attentions at using a cheaper 2 channel power amp to power the rear Atmos speakers with as opposed to spending more on an amp beffitting the front 2 channels? THe amp you'd use to power the Atmos speakers with doesn't need to be as acompliahed as an amp you'd use to power your front stereo pair with.

I guess it all depends upon where your priorities are.
 
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What Yamaha do you own?

It's an old HTR-5960 from ~2006. I used it for 6.1 for many years until I found out it had dialog lift hidden in its DSP modes. I added a pair of matching front height bookshelf speakers to try it out (It can only output up to 7.1 at once, so rear surround(s) were disabled, but the effect was excellent for moving dialog up to screen height.

I then did some experiments with my old "high on the side wall" surrounds with the ear level speakers disabled in multichannel stereo mode (thunderstorms, planes and the like) to hear how convincing Atmos/Auro/X might be and it was impressive so I started upgrading and adding more speakers. Before I knew it, I had 17.1 set up including "Scatmos" extraction to go beyond 11.1 and some extra side arrays for multiple rows of seats.

Now I'm looking at the Monoprice HTP-1 pretty closely. I could do "Scatmos" for side surround #2 and have full discrete decoding for everything else. I do my own dialog lift effect now using a mixer to send some L/C/R to the front heights to lift the sound stage up to screen height.
 
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It's an old HTR-5960 from ~2006. I used it for 6.1 for many years until I found out it had dialog lift hidden in its DSP modes. I added a pair of matching front height bookshelf speakers to try it out (It can only output up to 7.1 at once, so rear surround(s) were disabled, but the effect was excellent for moving dialog up to screen height.

I then did some experiments with my old "high on the side wall" surrounds with the ear level speakers disabled in multichannel stereo mode (thunderstorms, planes and the like) to hear how convincing Atmos/Auro/X might be and it was impressive so I started upgrading and adding more speakers. Before I knew it, I had 17.1 set up including "Scatmos" extraction to go beyond 11.1 and some extra side arrays for multiple rows of seats.

Now I'm looking at the Monoprice HTP-1 pretty closely. I could do "Scatmos" for side surround #2 and have full discrete decoding for everything else. I do my own dialog lift effect now using a mixer to send some L/C/R to the front heights to lift the sound stage up to screen height.



Indeed. The same guy who couldn't admit he was wrong about Atmos decoding without heights and slinked off into the darkness when it was obvious he lost.


That amp is

Minimum RMS Output Power for Front, Center, Surround,
Surround back
1 kHz, 0.7% THD, 8 Ω ...................................................... 115 W

So pretty bad testing method, 1khz tone, high THD. And very likely that 115W is with one channel driven.
 
That amp is

Minimum RMS Output Power for Front, Center, Surround,
Surround back
1 kHz, 0.7% THD, 8 Ω ...................................................... 115 W

So pretty bad testing method, 1khz tone, high THD. And very likely that 115W is with one channel driven.

It's only used for height channels, but thanks for worrying about it.
 
Thanks the sofa is a no go to move being a corner sofa and the entrance to the dining room. What about a small pair of tripole mk on the sides right up close to the rear wall or possibly the bipoles on the rear. How high would they go?. Starting to think this atoms project was a no go
The surround speakers can be placed between the side and the rear position, in other words not at a 90 degree angle, more like 135 degrees
 
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I am currently designing a dedicated room which I was planning to future proof for 9.1.6 but only initially install 7.1.4.

Due to constraints around access on the rear wall I can only install rear surrounds 300mm from side walls and the pair would be around 3.5m apart. Distance from MLP to back wall is 1.5m so angle would be around 130*. Distance from rear surrounds to side surrounds set at 95* would be 1.5m.

Two questions:

1 would I be better off with a 5.1.4 system with surrounds angled at 120* or is it worth persevering with rear surrounds? I can angle these towards MLP but will still be far apart and relatively close to side surrounds.

2 Would it be ridiculous to have a conventional 5.1.4 system, expanded to 7.1.4 but with front wides rather than 4nr surrounds?
 
It is general suggest that keeping the back surrounds is of more benefit than adding addsitional ceiling or height speakers. If you've at least 1m behind you then I see no reason why you could have back surrounds in your setup. The surrounds will ideally need to be at your seated head height though, are very close to this.

While having front width speakers can fill the gap between the front soundstagew and the surrounds, many seem to be disappointed with hust how little these speakers are actually engaged by Atmos soundtracks. I'd tend to suggest you'd get more from having back surrounds than if trying to replace them with front width speakers. You'd also engage the back surrounds while portraying 7.1 channel based soundtracks while the front width speakers are only really og much use if and when portraying Atmos soundtracks.

Would having front width speakers compensate for the absence of back surrounds? Probably not and I think you'd be better catered for with back surrounds rather than replacing them with front width speakers.
 
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I am currently designing a dedicated room which I was planning to future proof for 9.1.6 but only initially install 7.1.4.

Due to constraints around access on the rear wall I can only install rear surrounds 300mm from side walls and the pair would be around 3.5m apart. Distance from MLP to back wall is 1.5m so angle would be around 130*. Distance from rear surrounds to side surrounds set at 95* would be 1.5m.

Two questions:

1 would I be better off with a 5.1.4 system with surrounds angled at 120* or is it worth persevering with rear surrounds? I can angle these towards MLP but will still be far apart and relatively close to side surrounds.

2 Would it be ridiculous to have a conventional 5.1.4 system, expanded to 7.1.4 but with front wides rather than 4nr surrounds?

If you want 7.1.4 you put your rear surrounds at 120 and put your side surrounds at around 70 degrees (+/- 15). This will give you a much better effect than just surrounds at 120, IMO. You could still then add front wides at around 45-50 degrees.

Or yes, you could do 5.1.4 + front wides and have them at the conventional angles (~50-55 for front wides and 110-120 for surrounds. Many complain, however, that a lot of Atmos soundtracks don't use front wides much, if at all. However, most AVR/AVPs copy side surrounds to the front wides if you do 5.1.4 + FW.

What this means is that in essence, you have an array with front wides + side surrounds playing from the front wides and side surrounds + the folded rear content playing from the side surrounds (i.e. sides play from two sets of speakers which is an array and will image in-between instead making side surround sounds come from a "phantom speaker" in-between the front wides and 'side' surrounds. This means sounds for front wides will play from them, sounds for rear surrounds will play from the side surrounds and sounds for side surrounds will play from a point between the front wides and the side surrounds. Notice this images pretty much the same as 7.1.4 in option 1 except there the front wide sounds phantom image instead of the side surrounds.

Atmos, however can use something called "snap to" if the mixing engineer decides to use it, which means the front wides or other speakers might not phantom image because the sounds will be moved to the nearest physical speaker instead. I don't know how common it's used since you are generally unaware it's there without a way to compare. DTS:X doesn't use anything like that by comparison). Otherwise, effectively both options will sound very similar in actual practice for that "copy" reason and why the other guy's advice has no useful meaning whatsoever as it's clear he has no idea what the AVR/AVP does with 5.1.4 + FW. I'm doing 11.1.6 here, BTW.

If you want to do 9.1.6 in the future, I suggest you do the 7.1.4 option and add front wides later. Of course, unless you're going to hard mount the speakers, they could always be rearranged instead.
 
If you want 7.1.4 you put your rear surrounds at 120 and put your side surrounds at around 70 degrees (+/- 15). This will give you a much better effect than just surrounds at 120, IMO. You could still then add front wides at around 45-50 degrees.

Or yes, you could do 5.1.4 + front wides and have them at the conventional angles (~50-55 for front wides and 110-120 for surrounds. Many complain, however, that a lot of Atmos soundtracks don't use front wides much, if at all. However, most AVR/AVPs copy side surrounds to the front wides if you do 5.1.4 + FW.

What this means is that in essence, you have an array with front wides + side surrounds playing from the front wides and side surrounds + the folded rear content playing from the side surrounds (i.e. sides play from two sets of speakers which is an array and will image in-between instead making side surround sounds come from a "phantom speaker" in-between the front wides and 'side' surrounds. This means sounds for front wides will play from them, sounds for rear surrounds will play from the side surrounds and sounds for side surrounds will play from a point between the front wides and the side surrounds. Notice this images pretty much the same as 7.1.4 in option 1 except there the front wide sounds phantom image instead of the side surrounds.

Atmos, however can use something called "snap to" if the mixing engineer decides to use it, which means the front wides or other speakers might not phantom image because the sounds will be moved to the nearest physical speaker instead. I don't know how common it's used since you are generally unaware it's there without a way to compare. DTS:X doesn't use anything like that by comparison). Otherwise, effectively both options will sound very similar in actual practice for that "copy" reason and why the other guy's advice has no useful meaning whatsoever as it's clear he has no idea what the AVR/AVP does with 5.1.4 + FW. I'm doing 11.1.6 here, BTW.

If you want to do 9.1.6 in the future, I suggest you do the 7.1.4 option and add front wides later. Of course, unless you're going to hard mount the speakers, they could always be rearranged instead.
Thanks for response.

In terms of your recommendations for 7.1.4 conventional wisdom has side surrounds @ 90 - 100 and rear surrounds @ 135 - 150.

If I were to place sides @ 70 would they not be effectively acting as wides?

If I placed rears @ 120 these would be on side walls and therefore around 4.2m apart. My understanding is that it was bad to have rears too far apart as they are not really 'behind' you and therefore would just be duplicating sides?

I think basically what I am asking is if were to plump for rear surrounds if I keep at ear level I have the choice of them being either close together in the centre (around 1.5m apart but then further away from sides so better channel separation) or far apart near side walls (3.5m apart and closer to side surrounds). Which is preferable? I believe that different standards (Dolby, THX) say different things.

The ideal fix would be to mount one of the rear surrounds on the actual door but I have no idea how to do that.

Or alternatively given that it is not a massive room (5m x 4.2 x 2.6) would I be better off with 5.1.4 adhering strictly to Dolby rules?
 
It is general suggest that keeping the back surrounds is of more benefit than adding addsitional ceiling or height speakers. If you've at least 1m behind you then I see no reason why you could have back surrounds in your setup. The surrounds will ideally need to be at your seated head height though, are very close to this.

While having front width speakers can fill the gap between the front soundstagew and the surrounds, many seem to be disappointed with hust how little these speakers are actually engaged by Atmos soundtracks. I'd tend to suggest you'd get more from having back surrounds than if trying to replace them with front width speakers. You'd also engage the back surrounds while portraying 7.1 channel based soundtracks while the front width speakers are only really og much use if and when portraying Atmos soundtracks.

Would having front width speakers compensate for the absence of back surrounds? Probably not and I think you'd be better catered for with back surrounds rather than replacing them with front width speakers.
Thanks and sorry I missed your post at first instance.

I wasn't going to install wides at first instance; I'm assuming a better future Atmos iteration before committing.
 
Thanks for response.

In terms of your recommendations for 7.1.4 conventional wisdom has side surrounds @ 90 - 100 and rear surrounds @ 135 - 150.

If I were to place sides @ 70 would they not be effectively acting as wides?

If I placed rears @ 120 these would be on side walls and therefore around 4.2m apart. My understanding is that it was bad to have rears too far apart as they are not really 'behind' you and therefore would just be duplicating sides?

I think basically what I am asking is if were to plump for rear surrounds if I keep at ear level I have the choice of them being either close together in the centre (around 1.5m apart but then further away from sides so better channel separation) or far apart near side walls (3.5m apart and closer to side surrounds). Which is preferable? I believe that different standards (Dolby, THX) say different things.

The ideal fix would be to mount one of the rear surrounds on the actual door but I have no idea how to do that.

Or alternatively given that it is not a massive room (5m x 4.2 x 2.6) would I be better off with 5.1.4 adhering strictly to Dolby rules?

Wides are typically around 50-70, yes, but that's a 20 degree range. With all 34 Atmos speakers, they are 15 degrees apart between pairs, so having a set at 40-50 and another at 70-80 and another at 110-120 still gives you 20-30 degrees between pairs (L/R are typically at 30 degrees). If your distance behind you is short, that's your effective range for speakers in the room if you want 9 speakers on the floor. Or you can do 5.1.4 + FW at say 60/90/120 or 50/80/110. Given in a real Atmos theater, you can sit anywhere you want (i.e. speakers are static and the seats are everywhere), it's really more important to keep a nice angular distance (even as possible) between pairs than precise locations, IMO. I use 0/30/45/110/135/150 here (11 on the floor). Wides had to be at 45 instead of 50-70 due to where the front row right chair sits (I've got three rows of seats).
 
Wides are typically around 50-70, yes, but that's a 20 degree range. With all 34 Atmos speakers, they are 15 degrees apart between pairs, so having a set at 40-50 and another at 70-80 and another at 110-120 still gives you 20-30 degrees between pairs (L/R are typically at 30 degrees). If your distance behind you is short, that's your effective range for speakers in the room if you want 9 speakers on the floor. Or you can do 5.1.4 + FW at say 60/90/120 or 50/80/110. Given in a real Atmos theater, you can sit anywhere you want (i.e. speakers are static and the seats are everywhere), it's really more important to keep a nice angular distance (even as possible) between pairs than precise locations, IMO. I use 0/30/45/110/135/150 here (11 on the floor). Wides had to be at 45 instead of 50-70 due to where the front row right chair sits (I've got three rows of seats).
Ok thanks. How big is your room out of interest and did you do a build thread?
 
Ok thanks. How big is your room out of interest and did you do a build thread?
It's 12 feet in width and 24 feet long. I've got a thread on AVS, not here.
 
I am already running front presence speakers but would a notice the difference by adding some rear presence speakers as well?
 
I am already running front presence speakers but would a notice the difference by adding some rear presence speakers as well?

You should. It will allow panning to the rear and sounds overhead (unless the angle is too wide then the overhead sound is diminished, which is why I use Top Middle as well here).
 
Sorry if this has been asked before, i currently have a 5.1.4 system, i am about to upgrade my centre speaker. Is it possible to use my old centre speaker to make a 6.1.4 setup so would place it ear level rear middle of the room, or does atmos not work in that format?
 
Sorry if this has been asked before, i currently have a 5.1.4 system, i am about to upgrade my centre speaker. Is it possible to use my old centre speaker to make a 6.1.4 setup so would place it ear level rear middle of the room, or does atmos not work in that format?
No. Denon amps are formatted for the standard Atmos layouts of 5.1.4 or 7.1.4 with external amplification. The X6700 and X8500 expand this to thirteen channels giving a 7.1.6 or 9.1.4.
 
No. Denon amps are formatted for the standard Atmos layouts of 5.1.4 or 7.1.4 with external amplification. The X6700 and X8500 expand this to thirteen channels giving a 7.1.6 or 9.1.4.
Ok thanks, didn't think it would work.
 
No. Denon amps are formatted for the standard Atmos layouts of 5.1.4 or 7.1.4 with external amplification. The X6700 and X8500 expand this to thirteen channels giving a 7.1.6 or 9.1.4.

I'm sorry, but this is simply not accurate.

Sorry if this has been asked before, i currently have a 5.1.4 system, i am about to upgrade my centre speaker. Is it possible to use my old centre speaker to make a 6.1.4 setup so would place it ear level rear middle of the room, or does atmos not work in that format?

Yes, it will work (with some caveats). I have a Marantz 7012 (same software/decoders as Denon). Yes, you CAN configure 6.1.4 quite easily (set Amps to 11.1, but set Speakers / Speaker Config to 1 rear speaker and you have a center rear speaker configuration).

But there's a few additional things to consider (and these are all VERIFIED on my Marantz 7012).

1> DTS:X and Neural X upmixing both support 6.1.4 just fine.

2> Atmos DOES support 6.1.4 (verified with Dolby Atmos demos here). However, on AVS some discovered that some of the "fixed object" soundtracks (like from Disney) cause the Atmos renderer confusion as it forces "pairs" of speakers somehow and thus renders as 5.1.4 under those conditions. But with moving object soundtracks (most of the other studios and some newer Disney soundtracks), it will indeed make use of a rear center speaker. You can use Neural X instead on the base soundtrack instead if you want it to work (Height information may not be as accurate as actual Atmos decoding, but Neural X guesses pretty well).

3> Dolby DSU Upmixer does not support a rear center speaker for some reason (which is a bit odd since PLIIx did support a rear center just fine). The simple solution is to use Neural X instead for Dolby Digital, Dolby Digital + and TrueHD soundtracks if you want the rear center to operate. Neural X is vastly superior to DSU anyway, IMO.

4> Auro-3D's "2D" upmixer and the 3D one in Auro 13.1 capable receivers also supports rear center output (verified with Auro-2D here on Dolby Digital demos).
 
I'm sorry, but this is simply not accurate.



Yes, it will work (with some caveats). I have a Marantz 7012 (same software/decoders as Denon). Yes, you CAN configure 6.1.4 quite easily (set Amps to 11.1, but set Speakers / Speaker Config to 1 rear speaker and you have a center rear speaker configuration).

But there's a few additional things to consider (and these are all VERIFIED on my Marantz 7012).

1> DTS:X and Neural X upmixing both support 6.1.4 just fine.

2> Atmos DOES support 6.1.4 (verified with Dolby Atmos demos here). However, on AVS some discovered that some of the "fixed object" soundtracks (like from Disney) cause the Atmos renderer confusion as it forces "pairs" of speakers somehow and thus renders as 5.1.4 under those conditions. But with moving object soundtracks (most of the other studios and some newer Disney soundtracks), it will indeed make use of a rear center speaker. You can use Neural X instead on the base soundtrack instead if you want it to work (Height information may not be as accurate as actual Atmos decoding, but Neural X guesses pretty well).

3> Dolby DSU Upmixer does not support a rear center speaker for some reason (which is a bit odd since PLIIx did support a rear center just fine). The simple solution is to use Neural X instead for Dolby Digital, Dolby Digital + and TrueHD soundtracks if you want the rear center to operate. Neural X is vastly superior to DSU anyway, IMO.

4> Auro-3D's "2D" upmixer and the 3D one in Auro 13.1 capable receivers also supports rear center output (verified with Auro-2D here on Dolby Digital demos).
Thanks, might not sell my old centre channel yet then.
 
Note that Denon or Marantz AV receivers do not include a specific option within their settings for a single back surround, but you can facilitate this by connecting the solitary back speaker to just the left back speaker terminals. You'd then run the Audyssey calibration and the calibration would assume that you only want one single back speaker if it only detects one connected to the left back terminal. Note that Dolby Surround upmixing will not engaged the single back surround and that speaker will remain dormant whenever you angage DSU.

Dolby Atmos will not be portrayed correctly because of the way Atmos uses pairs of speakers to place objects. You can also expoerience issues with audio perception, resulting in a mono source located behind you being perceived in front of you. A single back surround isn't the best choice even in setups devoid of Atmos decoding and processing, but can be even worse in an Atmos setup.

There's also the issue as to what you are going to power the extra back speaker with? If you've only a 9 channel AV receiver then you'd need to employ external amplification to fascilitate a 10 channel 6.1.4, 10 speaker setup. You didn't mention wat AV receiver you have?
 
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I'm sorry, but this is simply not accurate.
I've looked at the amp assign and speaker connections in the manual for my Denon X6500. Can't find any mention or connection for a single Atmos speaker. They are all in pairs.
 
I've looked at the amp assign and speaker connections in the manual for my Denon X6500. Can't find any mention or connection for a single Atmos speaker. They are all in pairs.

You only use one of the surround back connectors (left one). Have you tried setting the speaker config to one surround back (click on it first and then you can move to the "two speakers" and change it to one. The picture diagram then even shows one speaker centered in the rear of the room.

Dolby Atmos will not be portrayed correctly because of the way Atmos uses pairs of speakers to place objects.

It handles properly used moving OBJECTS just fine as playing any Dolby Atmos demo ever made will demonstrate (and most movies). It's stationary pairs of objects that will be ignored. It should just sum them like PLIIx so I consider this a bug on Dolby's part, but given Neural X is a handy substitute, it's not that big a deal.

You can also expoerience issues with audio perception, resulting in a mono source located behind you being perceived in front of you. A single back surround isn't the best choice even in setups devoid of Atmos decoding and processing, but can be even worse in an Atmos setup.

Why would it be "even worse" ? It is what it is and it only does it at some frequencies if everything is aligned precisely (simple thing; move it off-center behind you slightly).

I found when I used a single speaker that turning it around so it bounced off the rear wall first got rid of 100% of that "in front of you" effect (Audyssey should be able to accommodate frequency changes as a result). If you have an extra bipole speaker you're not using, it would be perfect for this as well.

There's also the issue as to what you are going to power the extra back speaker with? If you've only a 9 channel AV receiver then you'd need to employ external amplification to fascilitate a 10 channel 6.1.4, 10 speaker setup. You didn't mention wat AV receiver you have?

Class D amps can be add for £40 or so on Amazon that will do the job just fine and offer an extra output if needed for something else like top surround.
 
Why would it be "even worse" ? It is what it is and it only does it at some frequencies if everything is aligned precisely (simple thing; move it off-center behind you slightly).

I found when I used a single speaker that turning it around so it bounced off the rear wall first got rid of 100% of that "in front of you" effect (Audyssey should be able to accommodate frequency changes as a result). If you have an extra bipole speaker you're not using, it would be perfect for this as well.


Class D amps can be add for £40 or so on Amazon that will do the job just fine and offer an extra output if needed for something else like top surround.


It is a fact that there’s a phenomenon termed “image reversal” where if we hear a mono sound directly behind us our brain will interpret it as coming from in front of us. This is one of the reasons why 6.1 was faded out and replaced by 7.1 as quickly as it was. It was even recommended that 6.1 layouts split the mono back signal signal between a pair of nack surrounds (dual mono) in order to prevent the psychoacoustic effect of image reversal.

According to Dolby themselves, the only mono scingle speaker in an Atmos setup should be the centre speaker. I'd assume this the very reason a single back surround not to be supported by DSU?

Dolby state the following:
There is an additional important consideration in expanding your system: new speakers must be added to your Dolby Atmos system in pairs. A new speaker on the right side of the room must be matched by a similar speaker on the left side of the room. This is true for speakers located on the floor as well as overhead. This pairing ensures a balanced soundstage. The exceptions to this rule are when you add speakers in the center or center back locations.

The OP is only considering a single back speaker in order to prevent a single forward firing centre speaker from going to waste. Why would he therefore go out and buy a bi-pole speaker? Besides which

The following should also be noted for reference:
Dolby does not recommend the use of dipole speakers for use at the listener level; the highly diffuse sound patterns of dipole speakers interfere with the accurate positioning of sounds in the three-dimensional soundstage that is Dolby Atmos.

A Bi-pole would also disperse the audio across the rear wall and would also be at odds with how Dolby exoect the back channels to be portrayed. Also note that a bipole would still suffer the effects of image reversal if locate behind yoi on its own.



I never mentioned the price of external amplifiers, simply that an additional external amp would be required if only using a 9 channel AVR. No idea as to why you'd take exception to anyone telling soimeone this?



Anyway, I wasn't addressing you when I posted my reply.



Also note that Yamaha don't even facilitate having a single back speaker with any of their AV receivers anymore. This has been the case for about the last 5 years now.



Can you technically have an Atmos setup with a single back surround speaker? Yes, it is possible with the AV receivers that still include the ability to run just one back suttound. Is it advisable or recommended to do so? Probably not given that it is at odds with the way Atmos works, it isn't supported by DSU and the fact that you'll experience image reversal if you've a single mono speaker located behind you.
 
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