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If you are powering one set of heights with 65w then you can get away with the other at 55w - at full power there will be a barely noticeable 0.8db difference.
According to calculators I only need 60w to get 115db from my 5.x.4 setup with 96db sensitivity speakers.
The problem is my height ceiling speakers are MA CT 280-IDC and they only have a sensitivity of 90dB

will that be better served with 100 wpc or will 50-55 be ok since they are ONLY effect speakers?
 

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Since they are 2-4db more sensitive than your ear level speakers then you need approx 1/2 the power to drive them to the same SPL, assuming they are the same distance.
If you only give them 55w then they will be about 1db quieter. use this to work out how much power you need : Peak SPL Calculator
 

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Where can I find a reliable source of all movies and tv shows in Atmos format?
 

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Since they are 2-4db more sensitive than your ear level speakers then you need approx 1/2 the power to drive them to the same SPL, assuming they are the same distance.
If you only give them 55w then they will be about 1db quieter. use this to work out how much power you need : Peak SPL Calculator
Is it a big deal if the atmos speakers are 1-3 dB quieter then the main ear level speakers? Will they not go as loud or go as loud and just distort?
Also, will my Dirac calibration lower the levels of all my ear level speakers because a ceiling/height is lesser power and can’t go as loud and therefore wasting my amp for the front 3 amp?
Lastly, how do you know that the atmos speakers are 2-4 dB less sensitive then my mains? I thought all mine were around 90-91 efficient all around?
 

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Is it a big deal if the atmos speakers are 1-3 dB quieter then the main ear level speakers? Will they not go as loud or go as loud and just distort?
Also, will my Dirac calibration lower the levels of all my ear level speakers because a ceiling/height is lesser power and can’t go as loud and therefore wasting my amp for the front 3 amp?
Lastly, how do you know that the atmos speakers are 2-4 dB less sensitive then my mains? I thought all mine were around 90-91 efficient all around?
I checked on the website and the Gold floor standers are rated at 86, and the surrounds at 88 - I may not have got that right as I wasn't certain I got the exact model. You will have to confirm that.
The less sensitive speakers will go as loud but will take more power to do so.
Dirac will set the levels according to the speaker sensitivity, distance from MLP and room gain. Nothing to do with amp power. So assuming the same distance and room gain but speakers which are say 3db less sensitive, then Dirac will set their levels 3db higher to compensate. This means the amp will have to supply twice as much power to drive them. But that doesn't mean you need an amp with twice as much power - it depends on how loud you listen. If you only listen at 85db the more sensitive speakers will likely only need 1w so the less sensitive will need 2w. But if you listen at 106db you will need 128w and 256w. You have to work out how many watts you need.
When you run Dirac what levels does it set the speakers to ? That will tell the difference in sensitivity, room gain and SPL loss due to distance. If the heights are set 3db higher then they will need more amp but again that depends on the listening volumes. According to the calculator I linked earlier, and assuming all your 11 speakers are 90db sensitive, 12' from MLP and near a wall , you only need 20w to get to 105db. Unless you are listening above that, then 55w will give you enough and have headroom for any extra 3db or so.
 

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According to the calculator I linked earlier, and assuming all your 11 speakers are 90db sensitive, 12' from MLP and near a wall , you only need 20w to get to 105db.
This may be true for all 11 speakers playing the same content (I haven't done the math myself) but the recommendation (THX, Dolby, SMPTE, CEDIA) is that each speaker be capable of reaching 105dB peak at the listening position, and 115dB for the subwoofers. I think Dolby has relaxed that a bit for surrounds in commercial cinemas (102dB ?), but I can't find that document right now.
 

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I checked on the website and the Gold floor standers are rated at 86, and the surrounds at 88 - I may not have got that right as I wasn't certain I got the exact model. You will have to confirm that.
The less sensitive speakers will go as loud but will take more power to do so.
Dirac will set the levels according to the speaker sensitivity, distance from MLP and room gain. Nothing to do with amp power. So assuming the same distance and room gain but speakers which are say 3db less sensitive, then Dirac will set their levels 3db higher to compensate. This means the amp will have to supply twice as much power to drive them. But that doesn't mean you need an amp with twice as much power - it depends on how loud you listen. If you only listen at 85db the more sensitive speakers will likely only need 1w so the less sensitive will need 2w. But if you listen at 106db you will need 128w and 256w. You have to work out how many watts you need.
When you run Dirac what levels does it set the speakers to ? That will tell the difference in sensitivity, room gain and SPL loss due to distance. If the heights are set 3db higher then they will need more amp but again that depends on the listening volumes. According to the calculator I linked earlier, and assuming all your 11 speakers are 90db sensitive, 12' from MLP and near a wall , you only need 20w to get to 105db. Unless you are listening above that, then 55w will give you enough and have headroom for any extra 3db or so.
Sorry, I should have said the 200s and 350 centre are 4th Gen. 89 and 90 dB sensitivity respectively

but I see your point and perhaps the 50-55 amp for those atmos pair will be ok after all...just didn’t want whole system to sufferfrom weak link
 

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This may be true for all 11 speakers playing the same content (I haven't done the math myself) but the recommendation (THX, Dolby, SMPTE, CEDIA) is that each speaker be capable of reaching 105dB peak at the listening position, and 115dB for the subwoofers. I think Dolby has relaxed that a bit for surrounds in commercial cinemas (102dB ?), but I can't find that document right now.
That's only true though if you actually listen AT reference level :)

Maybe that happens in the theaters you get paid to calibrate :p ... but most people don't come anywhere close to reference level. And, if they do, and are truly designing a system capable of clean reference level output, the questions discussed above shouldn't be happening because you shouldn't be cutting the margins so close.

Also (not responding to you, just general comment on the above) the surrounds + overheads are nearly always much closer to the listening position than the LCR speakers. So even if all speakers are equal sensitivity, it's likely the surrounds/overheads only need 1/2 the power at most.

In any "normal" home theater environment, I'd bet a lot of money that 50wpc is more than sufficient for the overhead speakers.
 
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This may be true for all 11 speakers playing the same content (I haven't done the math myself) but the recommendation (THX, Dolby, SMPTE, CEDIA) is that each speaker be capable of reaching 105dB peak at the listening position, and 115dB for the subwoofers. I think Dolby has relaxed that a bit for surrounds in commercial cinemas (102dB ?), but I can't find that document right now.
It's mentioned in the Dolby Atmos Specifications document: 105 dB for screen speakers; 105 dB for the overall surround array; 99 dB for each surround speaker. Doesn't really let us off the hook when we use single speakers for the surround "arrays".

The SPL for LFE is nominally 10 dB higher than the mains, but when considering bass management, a subwoofer needs to reproduce LFE plus redirected bass. In real-world movies that can add another 5 dB of signal heading to the subs -- 120 dB. :eek:

However, reference level in a small room (a home) does not require the same SPL as a cinema to provide the same subjective effect. Being that this is a subjective matter, it's hard to pin down a number with precision, but we can apply from -3 to -6 dB to our "reference" SPL target. 6 dB being 1/4 the power, that's a big deal for the amps and speakers.
 

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That's only true though if you actually listen AT reference level :)

Maybe that happens in the theaters you get paid to calibrate :p ... but most people don't come anywhere close to reference level. And, if they do, and are truly designing a system capable of clean reference level output, the questions discussed above shouldn't be happening because you shouldn't be cutting the margins so close.

Also (not responding to you, just general comment on the above) the surrounds + overheads are nearly always much closer to the listening position than the LCR speakers. So even if all speakers are equal sensitivity, it's likely the surrounds/overheads only need 1/2 the power at most.

In any "normal" home theater environment, I'd bet a lot of money that 50wpc is more than sufficient for the overhead speakers.
I'd agree with some of that. I'm definitely presenting a "best practices" approach, and even some of the rooms I work in won't truly play at reference. I was really just pointing out that 20 watts isn't gonna cut it, and that I disagree with the methodology used to calculate that number.
 

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It's mentioned in the Dolby Atmos Specifications document: 105 dB for screen speakers; 105 dB for the overall surround array; 99 dB for each surround speaker. Doesn't really let us off the hook when we use single speakers for the surround "arrays".

The SPL for LFE is nominally 10 dB higher than the mains, but when considering bass management, a subwoofer needs to reproduce LFE plus redirected bass. In real-world movies that can add another 5 dB of signal heading to the subs -- 120 dB. :eek:

However, reference level in a small room (a home) does not require the same SPL as a cinema to provide the same subjective effect. Being that this is a subjective matter, it's hard to pin down a number with precision, but we can apply from -3 to -6 dB to our "reference" SPL target. 6 dB being 1/4 the power, that's a big deal for the amps and speakers.
Thanks Roger, I think I missed the 105dB for the array part. So yup, when we have multiple discrete surrounds in a high channel count Atmos room, we aren't off the hook.

And I do agree that in small rooms, the SPL level doesn't need to be as high subjectively. But as I said above, 20w certainly won't meet the grade!
 

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I'd agree with some of that. I'm definitely presenting a "best practices" approach, and even some of the rooms I work in won't truly play at reference. I was really just pointing out that 20 watts isn't gonna cut it, and that I disagree with the methodology used to calculate that number.
Totally agree, and wasn't trying to "correct" you but just pointing it out for general reference. Many people have these target numbers in their head (105dB per speaker etc) and, certainly, if you're designing a high end pro dedicated room it's a good idea to adhere to the "best practices approach". But the actual requirements in the vast majority of "home theaters" is much easier to achieve because the real world listening volume is much lower; as Roger pointed out even subtracting 3dB (which is still very loud) cuts all the power requirements in half.

I certainly wouldn't quibble with anyone taking the approach "shoot for 105, even if I don't listen that loud at least I know I have plenty of clean headroom". But based on the many thousands of posts I've seen on forums like this even that is an aggressive target that could cause someone to spend more than they need to. HT is a lot cheaper if you pretend "reference level" is 100dB peak per speaker instead of 105dB :)
 

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Don't know if this is the right forum, but i've been discussing "real" and "fake" atmos on a discord. My techinal knowledge is very limited, so bear with and please explain in baby steps.

My side of the argument is, that several Atmos movies are release with so-called "fake" atmos. Minimal use of objects and basically and they basiccely mixxed om to 7.x.2/7.x4, with sound snapping to the closest avaiable.. This system use a snap tech that will detach the prober channels to what ever avaiable with any given setup. SPR, WotW and some Disney release (TlJ being the word).

The oppsode here is the real Atmos tracks, with very lively and active objects. One of the the ways i use to confirm this is by checking if my Front Heights are active. Be it an enhancement of the score or straight of opening of the frontstage, with effects of the like of. BR49 (Score and atmosphere, Zero Dark Thirty (basically a psyfosofy
of playing you in the middle of the scene, of movies using every speaker i have, for different things mind you,

Am i completely in the wrong here? And could someone un laymans terms explain why?
 

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Don't know if this is the right forum, but i've been discussing "real" and "fake" atmos on a discord. My techinal knowledge is very limited, so bear with and please explain in baby steps.

My side of the argument is, that several Atmos movies are release with so-called "fake" atmos. Minimal use of objects and basically and they basiccely mixxed om to 7.x.2/7.x4, with sound snapping to the closest avaiable.. This system use a snap tech that will detach the prober channels to what ever avaiable with any given setup. SPR, WotW and some Disney release (TlJ being the word).

The oppsode here is the real Atmos tracks, with very lively and active objects. One of the the ways i use to confirm this is by checking if my Front Heights are active. Be it an enhancement of the score or straight of opening of the frontstage, with effects of the like of. BR49 (Score and atmosphere, Zero Dark Thirty (basically a psysolophy of playing you in the middle of the scene, of movies using every speaker i have, for different things mind you,

Am i completely in the wrong here? And could someone un laymans terms explain why?
AFAIK both of those are real Atmos - it is up to the mixer to decide how much sound is sent to each Atmos speaker - some send lots and some don't send much.
I believe the Snap-To that you mention is just a different way of telling the setup which speaker to use but it is still Atmos.
 

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Am i completely in the wrong here? And could someone un laymans terms explain why?
The home Atmos format can use dynamic objects and have up to 9.1 channels (7.1 plus 2 height channels that are delivered as static objects). Just because the format has those options doesn't mean the mixer is required to use all of them. If all the options are not used, that doesn't mean it is no longer and Atmos track.
 

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AFAIK both of those are real Atmos - it is up to the mixer to decide how much sound is sent to each Atmos speaker - some send lots and some don't send much.
I believe the Snap-To that you mention is just a different way of telling the setup which speaker to use but it is still Atmos.
Using the team "real" Atmos may be been wrong. But as oneone who has 2 front heights It becomes with very obious when actual objects are in use or they just fall back to a bed mix.

It's real in the sense it uses the Atmos containter and metadata, just not to the fullest, imo.

It's just not using the Format to its fullest and frankly comes of as lazy, escpially on new titles. Just my 2 cent.

7.x.2 is the highest bed Atmos can containt without using objects`?

Guess im of the school that would still call 5.1 using one channel, a mono track, not matter the tech used (higher bitrate dynamics no-one withstanding)
 

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7.x.2 is the highest bed Atmos can containt without using objects`?
It's best to separate "Home Atmos" from the full cinematic mix because it's delivered a bit differently. The "bed" concept is a little looser, and is really best thought of as "static objects" within the total object payload.

As Sanjay noted above, cinematic Atmos has a 9.1ch bed (the standard 7.1 plus a stereo pair of "overhead surround" channels) which are the first 10 elements or "tracks" in the mix. Then, the mixer can include up to 118 objects as separate elements.

This fundamental structure is preserved when encoded for home release, but technically EVERYTHING (except the LFE) is converted into objects when the full cinematic mix is run through the "spatial coding" process to fit into the 11, 13, or 15 total element limit available for home.

So any "bed" or "channel" in the original mix becomes a "static object" with fixed coordinates. That is true for the 9 bed channels in the cinematic mix, so in a sense the answer is "yes, 7.1.2 is the highest bed count without using objects" -- if the mixer literally used only the first 10 tracks for the 9.1ch bed, and then left the other 118 tracks empty, it would spit out a home mix with 9 static objects + LFE.

BUT.... in another sense, given that the "beds" are delivered as static objects with fixed coordinates, in theory they could make a "bed like" mix for home that is >7.1.2 channels. And, in fact, that's what we see with "fixed print-out" 7.1.4 mixes, which for all purposes behave as an 11.1 channel-based mix since they don't scale. So is that a "bed without using objects"? Because it's behaving like one.
 

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RE: "Don't know if this is the right forum, but i've been discussing "real" and "fake" atmos on a discord. My techinal knowledge is very limited, so bear with and please explain in baby steps.

My side of the argument is, that several Atmos movies are release with so-called "fake" atmos. Minimal use of objects and basically and they basiccely mixxed om to 7.x.2/7.x4, with sound snapping to the closest avaiable.. This system use a snap tech that will detach the prober channels to what ever avaiable with any given setup. SPR, WotW and some Disney release (TlJ being the word).

The oppsode here is the real Atmos tracks, with very lively and active objects. One of the the ways i use to confirm this is by checking if my Front Heights are active. Be it an enhancement of the score or straight of opening of the frontstage, with effects of the like of. BR49 (Score and atmosphere, Zero Dark Thirty (basically a psyfosofy of playing you in the middle of the scene, of movies using every speaker i have, for different things mind you. Am i completely in the wrong here? And could someone un laymans terms explain why?"

***Well, Fakemos could just be a poorly mixed Dolby Atmos soundtrack. And, lack of use of the height channels is what most people complain about when they have invested in speakers for a Dolby Atmos layout. As far as I'm concerned, YMMV - with any soundtrack. Some DSU or DTS Neural: X upmixes can sound fantastic. (I'm really looking forward to DTS X: Pro on my Denon 6700H AVR with a firmware update, scheduled for this December, 2020.)

I've heard two channel upmixes that sound great and use channel heights effectively. So - in summation, it's not a Fakemos question, but more of how well the soundtrack is mixed in the first place and how it translates to your home theater. And, if it's not a native Dolby Atmos mix, how is it handled by upmixers.
 
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