Help with Atmos and a Yamaha RX-V765, please.

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Biddlefry1

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Apr 28, 2021
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Hi all.
Wonder if anyone can help me with this puzzle.
I've been enjoying listening to the Blu-Rays of releases like All Things Must Pass and especially enjoy the differences between the 5.1 and Atmos mixes. I think I prefer the Atmos mixes but here's the thing - I'm listening to it on an old Yamaha RX-V65 receiver which, while being Dolby Digital Plus capable, isn't Atmos capable!
My question is two-fold.
First, how is it processing the Atmos data from the Blu-Ray? I'm certainly not choosing any decoder settings on the Yamaha, just listening to the mix on the Straight setting. Is it automatically down-mixing it to the 5.1 speaker set up I have?
Secondly, if it can do that, what would it do with an Apple Dolby Atmos mix if I plugged an Apple TV 4K into it? Would the Apple device be happy pumping an Atmos mix through the Yamaha which would then down-mix it into 5.1 for me?
If so, I could enjoy Apple's new surround service but I would have a couple more years to save up for the full receiver/speaker Atmos set-up!
Hope someone can help. Cheers!
 

DuncanS

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Hi all.
Wonder if anyone can help me with this puzzle.
I've been enjoying listening to the Blu-Rays of releases like All Things Must Pass and especially enjoy the differences between the 5.1 and Atmos mixes. I think I prefer the Atmos mixes but here's the thing - I'm listening to it on an old Yamaha RX-V65 receiver which, while being Dolby Digital Plus capable, isn't Atmos capable!
My question is two-fold.
First, how is it processing the Atmos data from the Blu-Ray? I'm certainly not choosing any decoder settings on the Yamaha, just listening to the mix on the Straight setting. Is it automatically down-mixing it to the 5.1 speaker set up I have?
Secondly, if it can do that, what would it do with an Apple Dolby Atmos mix if I plugged an Apple TV 4K into it? Would the Apple device be happy pumping an Atmos mix through the Yamaha which would then down-mix it into 5.1 for me?
If so, I could enjoy Apple's new surround service but I would have a couple more years to save up for the full receiver/speaker Atmos set-up!
Hope someone can help. Cheers!
I believe that the Atmos mix is actually a 7.1/5.1 base 'layer' which contains all the audio (for heights, extra sides etc.), so that is what you are hearing in a non-Atmos set-up, so you are not listening to the optimised mix, consequently it will sound different in a lot of cases to a 5.1 mix, if one is available (I don't have Atmos either). In an Atmos system the processor looks at the audio object metadata embedded in the datastream, which gives the audio 'object' positioning information, and subtracts if from the base 7.1/5.1 'layer'. It then positions the metadata located sounds in a suitable way for the system that is being played on, its quite sophisticated. I forgot to go to an AES webinar on Atmos a while back, so I can't be more sure. DTS:X is similar object orientated system, but uses higher data rates.
 

Biddlefry1

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Apr 28, 2021
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Aha. Great explanation, Duncan. I understand how it's doing it now and why it would end up sounding different to the dedicated 5.1 mix. The fact that each audio object has a position in the sound field and that the processor can then interpret that in order to decide how best to distribute the object to the speakers is blowing my mind! It must be deciding on the object's volume in every speaker required for creating its virtual position in the room. Flippin' heck! So a Dolby Atmos mix makes the concept of the mixing engineer thinking in terms of channels utterly unnecessary. The processor is deciding on how the channels should be used according to whatever speaker set up the listener has.

Robert, I'm glad you think it's worth some thought. The reason I have come to this what-if scenario is due to an unsuccessful experiment with an Amazon 4K fire stick and Tidal. Unfortunately, once I had the Tidal app on the firestick, plugged it into my Yamaha receiver and paid the subscription for the quality required for Atmos mixes (HiFi tier) the app would not play the Atmos mix as apparently the app has to detect capability within the receiver in order for the option to be activated. I have not heard that this is the case with the Apple 4K TV. If anyone could shed some light on that, I would be most grateful.
 

fizzywiggs41

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I have a Yamaha RX V595a and it reads Atmos as Dolby Digital 5.1.

Most Atmos Blurays also have LPCM Surround and DTS MA 5.1 , and I always choose the DTS setting. (exception is John Lennon -Gimme Some Truth , where the Dolby is superior to the DTS)

This Makes me wonder if this Lennon Box set with Atmos switched to Dolby 5.1 over DTS 5.1 is a deliberate act of sabotage.
 
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