Atmos in 5.1.2: where does the top rear audio go?

[MathieuW]

Hi all,

I have a 4.0.2 setup. Four speakers on the ground in a square and 2 speakers above the two front speakers identified as top fronts in my AVR (Marantz cinema 30). When I run the speaker check from Dark Side of the Moon 50th anniversary edition, the top rear audio is played in the top fronts. This confuses me; my assumption was that audio from the top rears would go to the surrounds. Similar as the left/right side audio is played via the rear speakers in my setup.

Are there forum members with a x.x.2 setup that can confirm that all 4 top audio signals are played by the 2 speakers? Or is there a setting I missed.

It is great that I get as much use of those tops as possible, but I wonder if it doesn’t mess up the intended placement. For instance, backing vocals from the rear tops would be great, but in my situation they would play from the front tops and that might not combine well with any backing vocals in the surround rears.

 

[SeeMoreDigital]

Out of interest... If your Marantz Cinema 30 is able to support 7.4.6 or 9.4.4, why are you using it for just 4.0.2?

 

[riskylogic]

My understanding is that Atmos mixes have spatial positions rather than channels per se. The receiver assigns where tracks get played based on mix positions and how the receiver is calibrated.

 

[MathieuW]

Out of interest... If your Marantz Cinema 30 is able to support 7.4.6 or 9.4.4, why are you using it for just 4.0.2?

My Marantz is a much bigger supporter of multiple speakers than my wife. But my wife is better with our kids than the Marantz. Choices had to be made

 

[MathieuW]

My understanding is that Atmos mixes have spatial positions rather than channels per se. The receiver assigns where tracks get played based on mix positions and how the receiver is calibrated.

I think mixes can have channels and objects, but I have a limited grasp of what that actually is in the data stream. My idea was that rear tops (channel) or high behind objects remain behind the listener via the AVR decoding the signal to the speakers present. If the tops only have reverb (as some mixes only have that), combining all 4 tops at the front could spoil the effect. Maybe even cancel out?

 

[LuvMyQuad]

Objects or spatial positionings, semantics. it eventually comes down to a unique signal being amplified by a single amp and produced by a single speaker. A channel.

 

[steelydave]

My amp allows me to specify the physical location of my two height speakers, either front wall, front ceiling, middle ceiling or rear ceiling. Choosing one of these options controls what audio is actually sent to the speakers.

This is slightly oversimplified but this is what should/will happen with these options:

front wall/front ceiling: content meant for the front heights will go there, content meant for rear heights will go to your surround speakers on the floor
middle ceiling: content meant for front heights and rear heights will all be routed to the height speakers
rear ceiling: content meant for the front heights will go to your main floor left and right speakers, content meant for the rear heights will go there

The Atmos recommendation for .2 heights is that they should be basically "middle ceiling" somewhere between directly above the listener to 15 degrees in front of the listener. In this configuration, everything that would normally be sent to all four height speakers will be routed to the two speakers, but obviously what you lose is any front/rear separation for height information, ie if you had a sound moving from front left height to rear left height in a full .4 setup, in a .2 setup all the left height content whether or not it's front or rear would come from the one left height speaker.

The following is just personal opinion, so take it for what you will: After thinking about this for a long time, I decided to position my two height speakers as front ceiling height, rather than the Atmos recommended middle ceiling. Why? Because my feeling is that while the middle ceiling position is ideal for Atmos movies where the height aspect is about creating ambiance and atmosphere and "overhead effects" and so on, with listening to music in surround, my main priority is front/rear separation. For example, if there were backing vocals in the rear height speakers and I have a 5.1.2 setup, I'd rather hear them in the rear (floor) surround speakers than two middle ceiling speakers.

Obviously this is a compromise because in placing your two height speakers at the front you'll never hear anything from the rear height position, but 5.1.2 is a compromise in itself, and if I had to do the installation over again, I'd still make the same decision. There's no "right" answer really, so you should do what makes your listening experience the most enjoyable for you.

 

[marpow]

These two pictures are about 5 years old and things look a little different at the front, equipment wise, but we are not talking about that.

My seat is about middle of room, if you plumbed straight down my front heights would be about 3.5' in front of my chair, if you plumbed straight down my rears would be about 3' behind my chair.
The speakers in ceiling have movable/adjustable center tweeters and they are angled manually towards my chair.

My experience: my height speakers are farther distance from my head than the floor speakers. I have the height speakers +6db as I want to hear the heights without exception.
Atmos has so many variations as to how it ends up to the listeners ears, some are great and sum are duds and everything in the middle. If you are laying out a room, you basically want to lay out like mine. My room is 12' front wall X 14' long and 8' tall ceilings.
This configuration is close to near field listening, but plenty big enough to not be nearfield.
Metered amps are very good, especially when you are beginning Atmos, it mentally verifies what you think you hear.
I have 5.1 in my car, now that is nearfield listening and sounds really cool.
If I had a real big room, oh my, that would cost some bucks.
Final note; many times the signal is Dolby Atmos but there is nothing in the heights, so that can mess with your mind also.

 

[MathieuW]

My amp allows me to specify the physical location of my two height speakers, either front wall, front ceiling, middle ceiling or rear ceiling. Choosing one of these options controls what audio is actually sent to the speakers.

This is slightly oversimplified but this is what should/will happen with these options:

front wall/front ceiling: content meant for the front heights will go there, content meant for rear heights will go to your surround speakers on the floor
middle ceiling: content meant for front heights and rear heights will all be routed to the height speakers
rear ceiling: content meant for the front heights will go to your main floor left and right speakers, content meant for the rear heights will go there

The Atmos recommendation for .2 heights is that they should be basically "middle ceiling" somewhere between directly above the listener to 15 degrees in front of the listener. In this configuration, everything that would normally be sent to all four height speakers will be routed to the two speakers, but obviously what you lose is any front/rear separation for height information, ie if you had a sound moving from front left height to rear left height in a full .4 setup, in a .2 setup all the left height content whether or not it's front or rear would come from the one left height speaker.

The following is just personal opinion, so take it for what you will: After thinking about this for a long time, I decided to position my two height speakers as front ceiling height, rather than the Atmos recommended middle ceiling. Why? Because my feeling is that while the middle ceiling position is ideal for Atmos movies where the height aspect is about creating ambiance and atmosphere and "overhead effects" and so on, with listening to music in surround, my main priority is front/rear separation. For example, if there were backing vocals in the rear height speakers and I have a 5.1.2 setup, I'd rather hear them in the rear (floor) surround speakers than two middle ceiling speakers.

Obviously this is a compromise because in placing your two height speakers at the front you'll never hear anything from the rear height position, but 5.1.2 is a compromise in itself, and if I had to do the installation over again, I'd still make the same decision. There's no "right" answer really, so you should do what makes your listening experience the most enjoyable for you.

Thank you for the comprehensive explanation. I verified in the setup of the Marantz, and I configured the height speakers as follows:

Height speakers: 2
Layout: front height

Your simplification, much appreciated, is similar to my reasoning. Rear height should go to the surround speakers. Based on the channel test track on the Pink Floyd disc (and I also used 1 different one which was available on Apple Music), it does not go to the surround but to the front heights. I changed the setup in the AVR to Top front. This has no consequence for the test track, the rear height signal goes to Top front.

If you would run this or a comparable Atmos track, the rear height audio signal does go to the surround speakers?

BTW, my brother had a 7.2.2 setup and installed the two speakers in the middle of the ceiling as recommended indeed. For music he did not like the effect at all, for movies it was fine. A few months later he installed 2 additional speakers behind and moved the 2 middle speakers to the front. As music is much more important to me than movies, I installed front heights as well.

 

[MathieuW]

These two pictures are about 5 years old and things look a little different at the front, equipment wise, but we are not talking about that.

My seat is about middle of room, if you plumbed straight down my front heights would be about 3.5' in front of my chair, if you plumbed straight down my rears would be about 3' behind my chair.
The speakers in ceiling have movable/adjustable center tweeters and they are angled manually towards my chair.

My experience: my height speakers are farther distance from my head than the floor speakers. I have the height speakers +6db as I want to hear the heights without exception.
Atmos has so many variations as to how it ends up to the listeners ears, some are great and sum are duds and everything in the middle. If you are laying out a room, you basically want to lay out like mine. My room is 12' front wall X 14' long and 8' tall ceilings.
This configuration is close to near field listening, but plenty big enough to not be nearfield.
Metered amps are very good, especially when you are beginning Atmos, it mentally verifies what you think you hear.
I have 5.1 in my car, now that is nearfield listening and sounds really cool.
If I had a real big room, oh my, that would cost some bucks.
Final note; many times the signal is Dolby Atmos but there is nothing in the heights, so that can mess with your mind also.

View attachment 114817
View attachment 114818

This looks great and probably sounds even better! If only I planned ahead a bit more when our house was built 2 years ago, I would have prepared the ceiling for speakers. As it is a mixture of concrete and steel, that is not feasible. In theory it is possible of course.

 

[riskylogic]

Objects or spatial positionings, semantics. it eventually comes down to a unique signal being amplified by a single amp and produced by a single speaker. A channel.

Yes, but which channel depends on Atmos mix and speaker placement. With 5.1 it doesn't.

 

[LuvMyQuad]

Yes, but which channel depends on Atmos mix and speaker placement. With 5.1 it doesn't.

Agreed.

 

[barturtle]

Dolby Atmos has 7.1.2 bed channels with the .2 bed being top center. all other positions are done with objects. Objects will phantom based upon what your speaker config is, but once object height hits 100% it will only come out of the top speakers in my experience.

 

[ted_b]

Dolby Atmos has 7.1.2 bed channels with the .2 bed being top center. all other positions are done with objects. Objects will phantom based upon what your speaker config is, but once object height hits 100% it will only come out of the top speakers in my experience.

Not trying to be pedantic, but since this thread is about where Atmos sends stuff, let's use Atmos terminology. "Bed" only refers to ear-level speakers. The speakers above the ear are height layer (categorized as heights or tops, with slightly different mix ramifications, depending on processor).

 

[barturtle]

Not trying to be pedantic, but since this thread is about where Atmos sends stuff, let's use Atmos terminology. "Bed" only refers to ear-level speakers. The speakers above the ear are height layer (categorized as heights or tops, with slightly different mix ramifications, depending on processor).

Dolby themselves refers to the 7.1.2 as the bed. This is correct terminology.

https://professionalsupport.dolby.c...rence-between-beds-and-objects?language=en_US

"A Dolby Atmos input bed can be 2.0, 3.0, 5.0, 5.1, 7.0, 7.1, 7.0.2, or 7.1.2. Distribution of the bed in the Renderer is defined by the number of speakers in a particular room."

 

[splinter7]

In the speaker assignment menu on my Marantz SR5014, it visually and audibly shows that the rear heights are reassigned to the front or middle height placements (depending on what you select). Note: the SR5014 maxes out at 5.1.2 so maybe newer units may vary.

And someone with real knowledge could confirm or debunk that in that type of configuration, Atmos logic probably won't just automatically re-channel the everything to other heights but may further distribute some of the rear signals to surrounds or sides?

 

[ted_b]

Dolby themselves refers to the 7.1.2 as the bed. This is correct terminology.

https://professionalsupport.dolby.c...rence-between-beds-and-objects?language=en_US

"A Dolby Atmos input bed can be 2.0, 3.0, 5.0, 5.1, 7.0, 7.1, 7.0.2, or 7.1.2. Distribution of the bed in the Renderer is defined by the number of speakers in a particular room."

Thanks. My bad! I learn something new everyday. So when a bed includes a 7.1.2 (max size) then, really, Dolby Atmos is not theoretically needed, and no objects will be steered IF you are also 7.1.2 in your setup. Wild.

 

[MathieuW]

Dolby Atmos has 7.1.2 bed channels with the .2 bed being top center. all other positions are done with objects. Objects will phantom based upon what your speaker config is, but once object height hits 100% it will only come out of the top speakers in my experience.

Thanks, I think I understand. For the channel check to work, the signal are 4 objects (front height left + right and rear height left + right) at 100 procent height. My AVR places this fully in the two front height speakers. Same goes as the x.x.2 is used as a channel instead of an object, it goes to the front heights.

So only mixes which use objects including the rear height ‘space’ could be played differently than intended. As a made up example: a helicopter shown flying towards me might go from the fronts to the surrounds and stay at the heights at the front (while ideally the rear height would support the surrounds)?

 

[barturtle]

So only mixes which use objects including the rear height ‘space’ could be played differently than intended. As a made up example: a helicopter shown flying towards me might go from the fronts to the surrounds and stay at the heights at the front (while ideally the rear height would support the surrounds)?

Yes, but only if the height of the object was at 100%

If the object was say at 50% height going from center front to center rear, the processor is going to do its best to phantom it thru the room blending the sound from the front stereo pair (since you haven't a center) , with some amount of the sound coming from the top pair to create height, and then all 6 speakers to try to make it seem like the object is in the center of the room, and then finally out the rear speakers.

 

[MathieuW]

Thanks all for the informative responses, I appreciate the efforts to educate me in how the magic of Atmos actually works!