Dolby Atmos Pipeline Question

[Ryan K Georgieff]

Hey Guys,

I work at an Arthouse style theater and you guys have helped me out. I know this is a noob question but we only have a 5.1 system running off a cp500.

So what is the pipeline from Doremi to Atmos sound?

the newer CPs look like the information goes out to a Rj45 but then what? is it an Atmos amp to the speaker array?

the reason I'm asking is well our equipment is old. and I want to upgrade what I can before something brakes and someone makes a hasty decision without my input. Which has happened before. We are also an event space so we have other concerns about sound but that's for another topic.

bottom line is I want to upgrade us from 5.1 to 7.3.4 I have the speakers for 7.3.2 currently and my system has a Dante network. I don't know all the lingo but at least I know no-one makes a Dolby Atmos box you can just add. which is a shame.

however I have found a AES3 to Dante box by Appsys Pro Audio which looks promising.

[Leo Enticknap]

The immersive audio output from the CP850 and 950 is audio over IP, using either a customized implementation of AES67 or BluLink (user selectable). On the CP950 without Atmos capability, you can output the regular 16 channels (essentially, 7.1 tri-amped, plus surrounds, LFE, and assisted listening channels) in this form, as an alternative to the analog out via dual DB25 jacks. External D to A conversion then needs to be done, e.g. in Q-Sys, SDEC, or power amps with built in D to A (e.g. Dolby's own multichannel amplifiers).

However, genuine cinema Atmos is a major undertaking. You have to have a room design pre-approved by Dolby, and then commissioned by a Dolby-trained tech before they will issue the license that unlocks the IAB capability on your CP850 or 950. Without a certain number of side surround, top surround, and bass management channels (the exact number will depend on the physical characteristics of the room), they won't approve it. There are now cheaper and less restrictive IAB alternatives to Atmos, e.g. DTS:X.

[James Gardiner]

There is a special APP, a room design tool, that allows you to select all the supported speakers etc, soom size etc. as part of the certification process. I have it someplace, but I am on the road right now.
Maybe someone else can drop it here. Its not "restricted" in any way from memory and can be readily shared.

[Marcel Birgelen]

Our old screening room setup used the analog outputs on the CP850, which offers 16 analog outputs. While the CP850 can be made to talk to certain AES67 equipment, but it isn't stellar.

Our new setup uses the IMS3000 with AES67 into a QSys Core, which works pretty well, but we had a working AES67 with the CP850 beforehand. I tried Dante once in combination with our CP850 and that was no succes. If your entire sound system runs on Dante, then I'd probably invest in a AES67 to Dante bridge if your current setup doesn't already support AES67. Still, AES67 on Dolby devices comes with some caveats, like non-standard UDP ports, etc.

As for the license: Not that I want to encourage any abuse, but the matter of fact seems to be: nobody is actively checking anymore if your room is going to be built according to your design... Once you submit your room design they'll check if it meets their basic criteria and then they will issue you a license. Like James indicated, you're encouraged to use their app for that. We've done this process twice now for our own room and we never got any feedback of non-compliance...

[Steve Guttag]

Ryan,

Atmos for cinema is very much different than Atmos for home. I've never seen any commercial Atmos referred to by numbers (e.g. 7.3.4...which isn't even a consumer format that I've seen though I suppose one could have 3 LF channels with 4 overheads). Cinemas, as a rule, don't go beyond the ".1" or single subwoofer channel (though there may be multiples of subwoofers...they are all one channel). In Atmos, there are almost always Surround LFE channels to augment the surrounds into full-range channels but they don't get the extra number designation...there are just 2-8 of them located to augment (bass manage) the surrounds.

When clients approach me about Atmos, I ask them if they are willing to sink $100K-$150K into the system...if not, skip it. You can save that much money by sticking with 7.1. It isn't that you can't put in a more economical system, it's that as you cheapen it up, it starts resembling (and more importantly, sounding like) a 7.1 system that you got to spend a bit more money for. If you do it right (and the smallest room I've done has over 40 channels in it), then the room will get off of the track whatever they put into it. You need to think of speakers/amplifier channels as "resolution." The more you have, the more you can resolve of the audio as they finer detail they can locate and immerse the audio. Even when the audio is using the entire array (e.g. all top left surrounds)...the more you have, the better/more uniform the coverage. The more speakers/channels you have, the better and more discrete the location of an object. If you cheapen out, you waste your money because you end up with an expensive 7.1 system rather than a cheap Atmos system.

If you search and read Atmos reviews, there are plenty of people not seeing/hearing what the big deal is. More often than not, it is a value priced (yet expensive) system...particularly when combined with an uninspired soundtrack. There are quite a few tracks out there that are the equivalent to the "fake 3D" ones where it is clearly a 5.1 or 7.1 track (beds) where they sometimes use the top surrounds as arrays and, on very rare occasion, if at all, use objects.

The "App" that people are referring to is an Excel spreadsheet (and it uses macros, extensively, so you need to have a semi-current version of Excel to use it). It is called "DARDT" for Dolby Audio Room Design Tool. You put in your theatre's parameters (length, width, floor to ceiling height relationships, image size...etc.). It will start you off with how many speakers, and where they should go. It will have recommended and minimum quantities of speakers. As you put in specific make/model of speakers (it has a very large database of them plus you can add in your own by putting it the speaker's parameters), it will figure out the wattage needed and if you have any issues with either the speaker or amplifier power handling.

DARDT does have the "Kmart" button in the upper-right that will come up with the cheapest version of the system by pairing/culling surrounds (where the bulk of the amplifier channels are as well as speaker rigging/installation. But, again, if cheap is what you want, stick to 7.1.

Since you are a Doremi user, already, consider the Dolby IMS3000. It is the current evolution of the Doremi line and, for the cost of a [hefty] licensing fee (which you'd need even with the CP950A), it can become the Dolby Atmos processor (as well as the 5.1/7.1 one too). Dolby has tried to soften the cost blow on the hardware with the DMA amplifiers (ranging from 16-32 channels with an attractive cost/channel ratio, as compared to alternatives). Installation is also a snap as one just needs to connect the amps to the IMS3000 (or CP950A) via Ethernet cables. You don't have to buy the Atmos stuff when you buy the IMS3000 so you can think of it as an upgradable (which it is).

[Ryan K Georgieff]

Thank you everyone for your help!

Like i said I'm trying to get the ligo right.

I thought Dolby going from Speaker/LFE to Speaker/LFE/Height in number design was odd. As I think LeftCenter and RightCenter are more important channels than LeftBackSourround and RightBackSurrond and having leftcenter as a height channel seems like a downgrade, but that's just me.

Our set up is a small one screen theater 200+ seats in an old church so 100ft back, left to right is about 35ft

we run Doremi on a nec nc9000c audio goes to a usl,inc dax 602 then the cp500 to 3 qsc amps our PA is the dante with a Yamaha tf-1 linked to the cp500 via d25 so we can run all the speakers for a more balanced room augmentation enhancing the room acoustic relieving the feedback issues and giving a fake 5.1 to stereo movies we play.

I'm hoping we can run the aes3 into the dante using (FLX AES3+Dante card) from Appsys and then not worry about the cp500 and the older then dirt crossover and cm-80e monitor which is only half way hooked up but never seeing Atmos setup I wasn't sure what else I needed.

I understand the problems of running live audio through cinema speakers but that ship sailed years ago, and having a dual speaker system is just a waste of money when a properly used system can enhance any live event. I have gotten some push back about running a 5.1 system for live music but it is a truly encompassing experience. plus I grew up in the 70's listening to quad reel to reel so i really love good dynamics and spacial separation

[Carsten Kurz]

Just give up on Atmos. Cinema Atmos is way too expensive for your location. And home Atmos is not usable for DCPs.

[Leo Enticknap]

If he's content with non-theatrically licensed (e.g. from Swank) consumer content, e.g. BDs with consumer Atmos tracks on them, a budget immersive audio system based on, say, a JBL SDP-75 (the so-called "consumer Trinnov") could be a possibility.

[Marcel Birgelen]

The JBL SDP-75 does have sufficient AES inputs to connect your DCI server, so at least it integrates with some of the DCI equipment if you promote it to your audio processor. Don't know how it integrates with your automation though, but I guess it listens to similar commands via IP and serial than the Trinnov? My biggest gripe of trying to integrate "consumer grade" or let's rather call it "consumer oriented", because some of that high-end home cinema stuff is as or even more expensive than "the real deal", is that it makes a mess out of your audio routing, due to lack of compatible interconnects...

[Leo Enticknap]

I look after a few Bel-Air Circuit residence theaters in which the SDP-75 is used as the primary audio processor. There must be an API to enable IP control, because they are all controlled by Crestron stuff. I can't be any more specific than that, because my role is purely to look after the DCI projector and server, usually subcontracted to an AV vendor that does everything else. I also service two houses (one high end residence, and the other a film school auditorium) that are equipped for cinema Atmos, in which a CP850 or 950 is used for DCI and Atmos audio, and an SDP-75 for everything else. The outputs from both processors go into a Q-Sys (in the film school) and SDECs (in the residence theater), and from there to the power amps, which enables switching between the two processors' output.

Obviously, these are "money no object" solutions (and extravagant, even by Hollywood standards!), and therefore, I'm guessing, not an option for Ryan's theater. But for an immersive system that would at least enable consumer Atmos, and also be capable of playing AES3 regular DCI audio, maybe the SDP-75 is worth investigating?

[Carsten Kurz]

The TO have a NC900 and a DAX602/CP500 combo. Will they spend 30.000US$+ for an SDP-75 (and add amps, speakers and installation) into a home ATMOS system in order to play the occasional ATMOS Bluray?

[Mark Gulbrandsen]

I honestly never had one single customer interested in Atmos or DTS-X for that matter. And that's out of about 200 screens in 6 States that I serviced when I lived in Utah. And there were a number of customers that could have easily afforded it. Most of them bought recliners, or did remodeling instead. And as it turned out, the recliners did sell a lot more tickets.

[Dave Macaulay]

I think "real" Atmos is a fine aspiration for a cinema, but as said it's a major investment. Consumer Atmos is very very different from cinema Atmos.
I don't know if a licensed CP950A can decode and translate consumer Atmos to the cinema Atmos OOS system, don't think so but maybe. The HDMI signal from a BluRay can loop through the CP and it will decode Dolby consumer digital audio formats including TruAudio but I don't think consumer Atmos is on the list.
Not familiar with AES3. Dante systems can work with AES67 audio sources though.
The Atmos pipeline: Cinema Atmos plays an Atmos sound track's base 5.1 or 7.1 tracks normally. The Atmos sound objects are sent from the server to the CP850/950 via a network connection, either the existing command network or a dedicated server port and direct connection to the CP (latter is better). The CP gets the sound object data (digital audio and a direction vector) then maps it to the actual auditorium speakers to best get the right source direction. There is some limit to the number of OOS objects - 64 maybe - and essentially the more surround channels you have on the walls and ceiling the more accurate the direction mapping will be. Consumer ATMOS does not do that, it has extra surround channels and extra audio tracks for them. The mapping from sound objects to speaker locations is done in post production, not in your system. It's giving some directional sound objects but very basic compared to Cinema Atmos.
And to get a Cinema Atmos room you do need to work with Dolby and meet at least their minimum standards. This is not a "rubber stamp" approval, they won't give you the CP850/950 Atmos feature activation code without the approval. I suppose if you get one running from an approved design then upload the DAD file for another unapproved auditorium it will do its best with what it has but why do that?

[Harold Hallikainen]

I did a presentation on cinema technology to a non-technical group in 2015. I presented object-based sound as a difference in where the audio fragment panning was done. In 5.1 or 7.1, the panning is done at the mix stage with the resulting loudspeaker audio recorded and sent to the theater. With object-based, the audio fragments along with the panning instructions (source location) are sent to the theater, and the panning is done there. See https://bh.hallikainen.org/uploads/h...ma.pdf#page=38 .

On bed channels, these are not the "main sound" that appears on the AES3 outputs of the server. They are recorded as packets (one per frame), the same as object audio. Instead of being directed to a location in the theater, they are directed to specific loudspeakers or arrays. Note that SMPTE RDD52 section 10.3.1 ( https://ieeexplore.ieee.org/stamp/st...number=9161348 ) recommends the mainsound channels be silent when immersive audio is used. In practice, it appears that "backup" 5.1 or 7.1 audio is put there, but SMPTE recommends against it. During the drafting of RDD52, I did not see the harm in having backup audio in mainsound, but there was resistance to that. As I recall (which may not be accurate), there was a concern that theaters would play the backup when they thought they were playing IAB and not know that their IAB system was not working.

During the writing of the standard for IAB, there was discussion about putting the bed channels in main sound. I think DTS MAY have done this. Instead, the standard went with the entire immersive audio stream being self-contained (which I think is a good idea).

Harold

[Ryan K Georgieff]

Wow you guys gave me a lot to look at! that jbl is pretty awesome I could just run it through my mixer with no questions. but it is the same price as our projector and then I would need speakers! right now I am happy will adding some bed channels and vacuuming my EVs need to replace a cone or two. I grabbed a bargain of an amp from QSC and am going to separate the back Surrounds so we have 7.1 from there I am going to add some more speakers to the screen we have some already back there not doing anything some nice JBL wedges. they have been strict in the pass about having a live set of speakers and a cinema set of speakers which in my opinion is over kill on all fronts.