Atmos vs 5.1

[Sal1950]

That couldn't explain the issues I hear with DSOTM. Indeed given I have a 5.0 system I wouldn't even be able to hear that.

??? I don't know. The Atmos file sounds fantastic on my 5.2.4 rig ?

 

[jimfisheye]

The side vs rear compliance failure is outside of Atmos itself. Playing 5.x into a 7.x system is the issue.

5.1 was supposed to have two versions, right? Side and rear. Apparently it defaulted to side if not specified? Media player codecs were only written for default. So apparently side was used for a default even though it wasn't the intention because it didn't matter. Now 7.x comes on the scene, and much more now with Atmos demanding it. And now it matters! 5.1(side) coming out the side channels. So the Pink Floyd disc says "This isn't our fault! Um... swap your speaker cables?"

 

[Malhomme]

Read this...

Thanks for the link. It did not help that much, though being very informative. How the mixing is made, according to 'object status' is unclear. The number of objects themselves is puzzling. I remember Michael Jackson's Bad having 256 tracks of synths alone. So I gather objects can be premixes ? In my mixing experience (and iI have NONE atmos wise), you mix within a space, and not as objects that will be in different positions, because the mix wil unfold differently according to the number of speakers connected. I am probably thinking it wrongly here.

 

[himey]

Thanks for the link. It did not help that much, though being very informative. How the mixing is made, according to 'object status' is unclear. The number of objects themselves is puzzling. I remember Michael Jackson's Bad having 256 tracks of synths alone. So I gather objects can be premixes ? In my mixing experience (and iI have NONE atmos wise), you mix within a space, and not as objects that will be in different positions, because the mix wil unfold differently according to the number of speakers connected. I am probably thinking it wrongly here.

I doubt there are 256 tracks of synths playing simultaneously.

 

[himey]

Thanks for the link. It did not help that much

Search the member Sdurani at AVSForum under Atmos for information on how it really works and how it translates to consumer playback vs theater.

 

[jimfisheye]

Don't try to read any magic into the intermediary use of objects in the production process. Instead of the final mixing coming off the mixing board, the final panning of some mix elements is done on playback. When it works correctly, it sounds 1:1 how that mix would sound finished coming off the mixing board. You aren't hearing "objects" or anything from intermediary stages of the work. You're hearing the final mix as intended.

I mean... if everything works correctly and some rogue AVR with the decoder built in is in compliance. That's the rub, right? Is this system keeping the mix 1:1? All bets are off if one down mixes into a smaller speaker array of course but Atmos on the computer with the Dolby reference player app is 1:1 every time I try to sneak up on it and verify mixes.

The side vs rear faux pas only rears its head when playing 5.x into a 7.x system. This is impossible to correct cleanly because we have all these media players (and you know there are hardware AVRs in the mix too) errantly programmed to treat anything 5.1 as 5.1(side). This is a level worse than depreciated programming that omits 4.0 compliance (or anything in between 2.0 and 5.1).

Do we need to start putting 5.x files in 7.x containers like we do with 4.0 in 5.1? Might actually be the only solution. I think most autopilot speaker management on the computer or AVRs would down mix 7.1 to 5.1 by putting the rears to the sides. Making it transparent playing a 7.1 with blank side channels on a 5.1 system. Blank channels are free (zero extra file size) with FLAC.

 

[Owen Smith]

??? I don't know. The Atmos file sounds fantastic on my 5.2.4 rig ?

That's because you're decoding the Atmos. It sounds fine on my 5.0 when decoding the Atmos, but when playing just the True HD it sounds confused and muddy with everything in the middle, just like the test tones. You'd have to turn off Atmos and play the True HD as 5.2 to hear the issues.

 

[Owen Smith]

5.1 was supposed to have two versions, right? Side and rear.

You are making things up again, there were never two versions of 5.1.

 

[Owen Smith]

The side vs rear faux pas only rears its head when playing 5.x into a 7.x system. This is impossible to correct cleanly because we have all these media players (and you know there are hardware AVRs in the mix too) errantly programmed to treat anything 5.1 as 5.1(side).

The AVRs are doing what they are meant to do according to the specs. The errors came when 7.1 was added to the designs. This stems from initially we had 6.1 in DTS and Dolby Digital to add a centre rear. Then people wanted to split that into two rears, and at that point the die was already cast because of where the centre rear had been placed. If we'd never had 6.1 and just went straight to 7.1 they might have been added at the sides.

But also a lot of this comes from cinema use, and there in 5.1 the surrounds really are along the sides of the room. So it was natural for industry professionals to think of them like that and add things to the rear, overlooking that at home most people put the surrounds at the back of the room. And none of those industry professionals gave a damn about quad by this stage.

Do we need to start putting 5.x files in 7.x containers like we do with 4.0 in 5.1? Might actually be the only solution. I think most autopilot speaker management on the computer or AVRs would down mix 7.1 to 5.1 by putting the rears to the sides. Making it transparent playing a 7.1 with blank side channels on a 5.1 system. Blank channels are free (zero extra file size) with FLAC.

The solution is for AVRs to have a control that says whether 4.0 and 5.x use the rears or sides for playing the surrounds. It's a simple thing to add, you're just controlling which DAC is fed the relevant audio (and add caveat that in analogue direct mode this feature is inoperative, get your playback device to deal with it).

An issue with your solution on disc is that while silence encodes to virtually nothing in FLAC, it encodes quite poorly in MLP aka True HD and takes space up. I don't know what happens with silence in DTS and DTS HD MA.

 

[jimfisheye]

You are making things up again, there were never two versions of 5.1.

Just the messenger here!

Audio codecs list 5.1(side) and 5.1(rear) as options.
All the commercial media I've seen with 5.1 program denotes it as 5.1(side) when it is clearly intended to be 5.1(rear).

And yes, AVRs and media players are in fact doing what they are told! Putting 5.1(side) to the side speakers!
The problem is some of those media players will not understand the 5.1(rear) format. Instead of that being corrected, media was released incorrectly. Probably because 5.1 vs 5.1 always hit rear speakers, right? So now you can't release in 5.1(rear) because it might not be backward compatible and might not play at all.

It happened. This is what the Floyd disc is talking about. You see the format options listed for audio codecs.

 

[AYanguas]

.......... I don't know what happens with silence in DTS and DTS HD MA.

Fortunately, my Denon DTS and DTS HD-MA decoding of a source 5.1 file sends the surround channels to both Sides and Rears. It also displays it correctly in the display with the four surround speakers activated. Some even say that it is correctly done, by lowering about 3dB the level to keep the overall level with the double of speakers. This does not "send back" the sound full to the rears, because both sides and rears "image" the sound in between, but it sounds less intrussive than only with the sides.

Thats why I much prefer to listen 5.1 with DTS sources, because other sources (AC3, 5.1 PCM/FLAC multichannel) are decoded only to the Side Surrounds.

In Atmos (7.1.x) the Sides works well (when the mix is good), but for 5.1, and specially old Quad 4.0 mixes, the Sides (at 90º) are too intrussive, and Quad is more balanced using the Rears. For that sources, when not encoded in DTS, I have to generate 7.1 with blank Sides. Thanks @HomerJAU for that option in MMH.

 

[Sal1950]

5.1 speaker layout was not intended to be like Quad with the listener equal distant from all 4 speakers
"Rear" speakers in 5.1 are intended to be to the side or just slightly behind the MLP.
Only for 7.1 are the "Rears" pushed way to the rear, and "Side" surrounds are now in the approx same position as the "Rears" used to be in 5.1.

 

[LuvMyQuad]

5.1 speaker layout was not intended to be like Quad with the listener equal distant from all 4 speakers
"Rear" speakers in 5.1 are intended to be to the side or just slightly behind the MLP.
Only for 7.1 are the "Rears" pushed way to the rear, and "Side" surrounds are now in the approx same position as the "Rears" used to be in 5.1.

That's how I understand it as well

 

[MidiMagic]

That is unrelated to Atmos. Dolby introduced "Dolby Surround" which does not accurately decode any of the old Dolby Surround, Pro Logic or Pro Logic II formats. But there was no reason why Atmos could not have co-existed with those.

Could have, but doesn't, so Dolby makes more money. You have to rebuy your Dolby Surround videos for them to work on new systems. More royalties.

 

[par4ken]

Could have, but doesn't, so Dolby makes more money. You have to rebuy your Dolby Surround videos fort them to work on new systems. More royalties.

There is no shortage of Dolby Surround or Dolby PLII decoders available on the used market so what is the problem? While I hear what you are saying you can't expect old technology to be carried over forever. I would bitch more about no SQ and QS decoders being included in modern equipment. Stick to vintage!

 

[par4ken]

5.1 speaker layout was not intended to be like Quad with the listener equal distant from all 4 speakers
"Rear" speakers in 5.1 are intended to be to the side or just slightly behind the MLP.
Only for 7.1 are the "Rears" pushed way to the rear, and "Side" surrounds are now in the approx same position as the "Rears" used to be in 5.1.

That is pretty much the set up that I use for Quad (and all surround). Just minus the centre and sub, also the rear/sides are matched to the fronts. Nothing really new since the seventies!

 

[key_wiz]

5.1 speaker layout was not intended to be like Quad with the listener equal distant from all 4 speakers
"Rear" speakers in 5.1 are intended to be to the side or just slightly behind the MLP.
Only for 7.1 are the "Rears" pushed way to the rear, and "Side" surrounds are now in the approx same position as the "Rears" used to be in 5.1.

This set up is more realistic to how people live. Few people are going to set up a sound system with all four speakers an equal distance from the listener. Most people’s living rooms have the couch towards the back of the room. Not in the middle.

 

[SeeMoreDigital]

5.1 speaker layout was not intended to be like Quad with the listener equal distant from all 4 speakers
"Rear" speakers in 5.1 are intended to be to the side or just slightly behind the MLP.
Only for 7.1 are the "Rears" pushed way to the rear, and "Side" surrounds are now in the approx same position as the "Rears" used to be in 5.1.

That's the modern 5.1 speaker layout, which was introduced when 7.1 became a thing. The original 5.1 speaker layout from the early 2000's placed the rear speakers a lot further behind the listeners head...

 

[AYanguas]

That's the modern 5.1 speaker layout, which was introduced when 7.1 became a thing. The original 5.1 speaker layout from the early 2000's placed the rear speakers a lot further behind the listeners head...

And even in a high position. To get the sound from a little above to avoid possible furniture obstacles.

With the arrival of height speakers for immersive 3D formats, the surrounds had to return to ear level (floor) to leave effective separation with the heights.

 

[Stephen W Tayler]

this is more or less the layout I use for mixing 5.1....