Dolby Atmos and TrueImage

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thorne Posted: Sun, Feb 6 2022 10:49 PM

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Hi

is it true that the latter is B&O’s version of the former?  And what extra do I need on top of my present set up?

Eclipse1, 2 x Beolab 18s (front), 2 x Beolab 6000s ((rear) and Beolab 2

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Geoff Martin replied on Mon, Feb 7 2022 8:11 AM

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True Image is an up- /down-mixer that dynamically re-configures itself based on the channel allocations of the input and output configurations.

For example

• if you have a 2.0 input and a 5.1 output, then it will upmix
• if you have a 5.1 input and a 2.0 output, then it will downmix
• if you have a 7.1 input and a 7.1 output, then it will do nothing (assuming the control sliders are set to "do nothing")

Although Dolby Atmos contains an up-/down-mixer, it is also:

• a loudspeaker configuration description that includes "height" channels (for most home audio systems, this is up to 7.1.4 channels - but it can include more channels)
• a way of encoding a stream so that the appropriate signals get to the right loudspeakers
• a way of encoding audio channels (e.g. Left Front - which is a signal intended to be played by a Left Front loudspeaker) and audio objects (e.g. a sound that should appear to sound in the left-back-upper corner of the room; within reason, regardless of which loudspeakers you have any where they are)
• capable of "virtualizing" loudspeakers - using processing applied to the outputs of some loudspeakers to make it appear as though there is another loudspeaker is a place where there is not - as is available in Beosound Stage, for example.
• some other stuff that is complicated beyond the requirements of this list.

So, if you have a stream that is encoded in Dolby Atmos AND more than the 7.1 channels have audio signals on them, then you will need a Dolby Atmos decoder to hear the content on those extra channels.

Also, note that True Image's and Atmos's up-/down-mixers are different. They provide the same function, but do it differently. (Pasta Carbonara and Sushi are both "dinner" -  but they're also very different.)

Hope this helps.

Cheers
-geoff

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swestland replied on Mon, Feb 7 2022 10:57 AM

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Geoff Martin:

True Image is an up- /down-mixer that dynamically re-configures itself based on the channel allocations of the input and output configurations.

For example

 

• if you have a 2.0 input and a 5.1 output, then it will upmix
• if you have a 5.1 input and a 2.0 output, then it will downmix
• if you have a 7.1 input and a 7.1 output, then it will do nothing (assuming the control sliders are set to "do nothing")

 

Although Dolby Atmos contains an up-/down-mixer, it is also:

 

• a loudspeaker configuration description that includes "height" channels (for most home audio systems, this is up to 7.1.4 channels - but it can include more channels)
• a way of encoding a stream so that the appropriate signals get to the right loudspeakers
• a way of encoding audio channels (e.g. Left Front - which is a signal intended to be played by a Left Front loudspeaker) and audio objects (e.g. a sound that should appear to sound in the left-back-upper corner of the room; within reason, regardless of which loudspeakers you have any where they are)
• capable of "virtualizing" loudspeakers - using processing applied to the outputs of some loudspeakers to make it appear as though there is another loudspeaker is a place where there is not - as is available in Beosound Stage, for example.
• some other stuff that is complicated beyond the requirements of this list.

 

So, if you have a stream that is encoded in Dolby Atmos AND more than the 7.1 channels have audio signals on them, then you will need a Dolby Atmos decoder to hear the content on those extra channels.

Also, note that True Image's and Atmos's up-/down-mixers are different. They provide the same function, but do it differently. (Pasta Carbonara and Sushi are both "dinner" -  but they're also very different.)

Hope this helps.

Cheers
-geoff

What happens if I have a 5.1 source, and a 5.1 speaker group which selected as TrueImage in Sound mode Movie. In that case the sound info always mentions downmix. But what is the TrueImage processor downmixing in that case? 

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Geoff Martin replied on Mon, Feb 7 2022 3:06 PM

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swestland:

What happens if I have a 5.1 source, and a 5.1 speaker group which selected as TrueImage in Sound mode Movie. In that case the sound info always mentions downmix. But what is the TrueImage processor downmixing in that case? 

IF

• you have a 5.1 input stream and 
• 5 main loudspeakers + a subwoofer in your Speaker Group, and
• Balance, Fader, Stage Width, and Envelopment, are all set to the middle values

THEN True Image will be the same as 1:1 mode.

However, if you make any changes to any of the above "IF"s, then the "THEN" will no longer be true.

Out of curiosity - which TV do you have? I'd like to duplicate the test here...

Cheers

-geoff

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swestland replied on Mon, Feb 7 2022 7:58 PM

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Geoff Martin:

swestland:

What happens if I have a 5.1 source, and a 5.1 speaker group which selected as TrueImage in Sound mode Movie. In that case the sound info always mentions downmix. But what is the TrueImage processor downmixing in that case? 

IF

 

• you have a 5.1 input stream and 
• 5 main loudspeakers + a subwoofer in your Speaker Group, and
• Balance, Fader, Stage Width, and Envelopment, are all set to the middle values

 

THEN True Image will be the same as 1:1 mode.

However, if you make any changes to any of the above "IF"s, then the "THEN" will no longer be true.

Out of curiosity - which TV do you have? I'd like to duplicate the test here...

Cheers

-geoff

I have a Eclipse 55 2nd gen. BeoLab 19 and a 4 speaker shape in the back for left/right surround. My movie sound mode has all sliders at the middle position. 
But will the sound info indicate that it’s 1:1 or just says down mix. If I select it as 1:1 then sound info processings says ‘none’ which is correct I guess. 

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thorne replied on Thu, Feb 10 2022 4:36 PM

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Hi Geoff. That helps enormously. Thanks a lot. One further question. You use the word ‘automatically’. So does that mean I don’t have to enable True Image?  It just comes in as and when needed

Thanks

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Simon Weir replied on Thu, Feb 10 2022 7:15 PM

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Evening Geoff.

To support others on the thread.  Whichever sound group I select on my Eclipse MK2 55”, the sound info only ever states downmix or TrueImage, be it 5.1 or 7.1 variants matching the source playing 5.1 or 7.1.  Rest of setup is in my signature below.

Like others all my sound modes and speakers groups are as the default setting.  I use sound mode drama for most viewing, unless watching a film, then it is movie, or listening to music and then I use music.

I have had a MK1 Eclipse 55, and before that I have had an Avant 55, and as long as I have known it the only output info states downmix or TrueImage.  I know this because I often have the B&O app open on my iPad when changing sources ti see the settings change because this is quicker than selecting the B&O app on the TV via the BeoRemote, plus it doesn’t change the screen image or sound.

I can force to 1:1 if I use the custom sound mode which I set to 1:1.

Be good to know if we should select other settings in the granular menus.

Thanks,

Simon