Impact of lossy compression when streaming Atmos

QuadraphonicQuad

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LuvMyQuad

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Lots of us don't have more than 5.1, but the Atmos mixes can still be enjoyed. Tons of new surround content for those of us with 5.1 systems.
I find that Atmos tracks mix down to 5.1 quite nicely. Nothing seems to get lost. Nothing seems to get overemphasized. Maybe a bit different placement.
 

Ephi82

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I don’t listen to numbers, I listen to music.

I’ve have multiple Blu rays with ATMOS mixes, and the same on Apple Music, and they don’t displease me one bit. I have decent gear….maybe my 63 year old ears are just old……?
 

marcb

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I find that Atmos tracks mix down to 5.1 quite nicely. Nothing seems to get lost. Nothing seems to get overemphasized. Maybe a bit different placement.
Am I the only one who finds - on Apple Music - the rears for Atmos mixes folded down to 5.1 to be about 3dB quieter than the rears for the true 5.1 and quad mixes?
 

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Am I the only one who finds - on Apple Music - the rears for Atmos mixes folded down to 5.1 to be about 3dB quieter than the rears for the true 5.1 and quad mixes?
My comment was directed exclusively toward fold downs from disc and/or files. I actually can't fold Apple music Atmos streams down to 5.1, as the AVP I use wont allow it. If it comes in as Atmos, and the equipment is Atmos capable, it has to be processed as Atmos (I'm told its a Dolby requirement???) . The only other valid option on my AVP is a fold down to stereo. For whatever reason, that is allowed.

I could probably do it by changing the AVP setup to indicate there are no height channels. But I haven't done that (why would I ?)
 

marcb

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My comment was directed exclusively toward fold downs from disc and/or files. I actually can't fold Apple music Atmos streams down to 5.1, as the AVP I use wont allow it. If it comes in as Atmos, and the equipment is Atmos capable, it has to be processed as Atmos (I'm told its a Dolby requirement???) . The only other valid option on my AVP is a fold down to stereo. For whatever reason, that is allowed.

I could probably do it by changing the AVP setup to indicate there are no height channels. But I haven't done that (why would I ?)
Sorry I was just piggybacking on your post to ask a question.

FWIW, my AVR is atmos capable too. If you really care enough to experiment, turn your atmos speakers off. Your AVR should then fold Atmos down to 5.1.

Could my ATV4K (or my AVR) be throwing out information rather than folding into the rears? I don’t think so, but maybe I’m wrong.
 

Ephi82

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Maybe I misunderstand, but if your AVR is set up for no height/ATMOS speakers, ATMOS height content is part of what is sent to the surrounds?

If the AVR is set up for an ATMOS configuration,with height speakers, it uses the ATMOS data and sends it to the heights…
 

LuvMyQuad

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Maybe I misunderstand, but if your AVR is set up for no height/ATMOS speakers, ATMOS height content is part of what is sent to the surrounds?

If the AVR is set up for an ATMOS configuration,with height speakers, it uses the ATMOS data and sends it to the heights…
That's how I understand it.
 

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Am I the only one who finds - on Apple Music - the rears for Atmos mixes folded down to 5.1 to be about 3dB quieter than the rears for the true 5.1 and quad mixes?
When you run Dolby's channel ID test, do the rears seem lower in volume than the fronts?
 

marcb

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Maybe I misunderstand, but if your AVR is set up for no height/ATMOS speakers, ATMOS height content is part of what is sent to the surrounds?

If the AVR is set up for an ATMOS configuration,with height speakers, it uses the ATMOS data and sends it to the heights…
That’s my understanding as well.

But I’m wondering if maybe the ATV4K or my AVR might be doing something else.

Edit: Now that I think about it both my main system and my bedroom system (w/ a soundbar + Sub + 2 surrounds) seem to exhibit the issue, so it’s probably not the AVR.

I only put 2+2 together recently when I thought something didn’t seem right with my surrounds, so I balanced them. Then when I went to another album, they were way off in the opposite direction. Eventually I found it seemed to be an Atmos vs non-Atmos thing.
 
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marcb

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When you run Dolby's channel ID test, do the rears seem lower in volume than the fronts?
I’ll need to try that.

But it’s not even close just listening by ear. A delta of 3-4dBs is not small. And that’s what I seem to be consistently finding with Atmos vs non-Atmos. I need to test more to make sure though.
 

RustyStatic

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Finding this thread fascinating - thank you all… FWIW, I don’t have the deep technical background or understanding that many of you folks do, although I’ve been a recording musician for a few decades now and am fairly confident in my ears. But, offering a layman’s perspective, through my experiences as of late, I’ve been able to arrive at a few personal truisms:

1. I wondered if upgrading to Atmos was gonna be just snake oil or something transformative… and had to know, so I converted to a 5.2.2 by throwing some nice Focal speakers on the ceiling of my fairly small listening space. Initially using Gentle Giant’s Free Hand and The Lost Voices of Hagia Sophia discs, I immediately decided it was worth the money to upgrade and that it offered a heightened experience (pun intended 😬).

2. I absolutely can and do get a thrill out of the Atmos titles I stream from Apple TV4K, particularly the ones that are exclusive to streaming. Perfectly happy doing this.

3. However, where I’ve had the opportunity to do an A/B between Atmos discs and Atmos streaming, the discs have had a very clear advantage. This is not what I would prefer, so my confirmation bias would certainly be in the other direction. Maybe it’s a matter of fidelity, but I haven’t really been able to hear big differences there once I'm north of 16bit/44.1kHz in the past if I’m honest. Even though what’s streaming is supposed to be the same mix as what's on the discs AFAIK, it’s just not manifesting itself that way when I A/B. From a disc, the separation is just so much better and the heights are way more active and in play… so much so, that I’m kinda resigned to “if there's an Atmos mix, I’m gonna try to buy the disc if available”—which I’d rather not due to the expense.

I haven’t done extensive comparisons in the same way for 5.1 titles because for the most part I either have them on disc already, have ripped them from there and default to playing from JRiver, or if it’s a streaming quad title that never had an official digital release, that’s different enough from a conversion that I might prefer one or the other but it wouldn’t be an A/B.

Things that make you go hm.
 
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HomerJAU

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There’s no doubt that lossless can sound better than lossy (lossless disc vs steaming). In my experience higher volume playback reveals this more than at low volume.

With legacy quad I’ve found some streaming quads easily sound better, especially if the conversion has come from SQ, where the fidelity and separation from the digitally encoded master (steaming) is more pleasing than from the matrix decode and conversion to digital.
 

Ephi82

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Finding this thread fascinating - thank you all… FWIW, I don’t have the deep technical background or understanding that many of you folks do, although I’ve been a recording musician for a few decades now and am fairly confident in my ears. But, offering a layman’s perspective, through my experiences as of late, I’ve been able to arrive at a few personal truisms:

1. I wondered if upgrading to Atmos was gonna be just snake oil or something transformative… and had to know, so I converted to a 5.2.2 by throwing some nice Focal speakers on the ceiling of my fairly small listening space. Initially using Gentle Giant’s Free Hand and The Lost Voices of Hagia Sophia discs, I immediately decided it was worth the money to upgrade and that it offered a heightened experience (pun intended 😬).

2. I absolutely can and do get a thrill out of the Atmos titles I stream from Apple TV4K, particularly the ones that are exclusive to streaming. Perfectly happy doing this.

3. However, where I’ve had the opportunity to do an A/B between Atmos discs and Atmos streaming, the discs have had a very clear advantage. This is not what I would prefer, so my confirmation bias would certainly be in the other direction. Maybe it’s a matter of fidelity, but I haven’t really been able to hear big differences there once I'm north of 16bit/44.1kHz in the past if I’m honest. Even though what’s streaming is supposed to be the same mix as what's on the discs AFAIK, it’s just not manifesting itself that way when I A/B. From a disc, the separation is just so much better and the heights are way more active and in play… so much so, that I’m kinda resigned to “if there's an Atmos mix, I’m gonna try to buy the disc if available”—which I’d rather not due to the expense.

I haven’t done extensive comparisons in the same way for 5.1 titles because for the most part I either have them on disc already, have ripped them from there and default to playing from JRiver, or if it’s a streaming quad title that never had an official digital release, that’s different enough from a conversion that I might prefer one or the other but it wouldn’t be an A/B.

Things that make you go hm.
Up until recently, I wasn’t sure that I could hear a big difference between ATMOS on Blu ray vs on Apple Music/Apple TV. That got blown up when I listened to Beatles Abbey Road in both formats. The Blu Ray had much better extension and detail, heard acutely in the surrounds, and I don’t mean by a little. That said, the connivence of being able to cruise through thousands of recordings using just a little silver remote is undeniable, not to mention the fast growing number of available surround and ATMOS releases.
 

perzon57

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Up until recently, I wasn’t sure that I could hear a big difference between ATMOS on Blu ray vs on Apple Music/Apple TV. That got blown up when I listened to Beatles Abbey Road in both formats. The Blu Ray had much better extension and detail, heard acutely in the surrounds, and I don’t mean by a little. That said, the connivence of being able to cruise through thousands of recordings using just a little silver remote is undeniable, not to mention the fast growing number of available surround and ATMOS releases.
And most of the Atmos releases are only on streaming, so no disc. I wouldn't miss out on all that good music in Atmos because the fidelity is a little poorer. To me it sounds quite alright. :cool:
 

Ephi82

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Another recent discovery. I don’t know if it happened with a re boot of the Apple TV or a sw update, but my Apple TV decided that the Apple Music Audio quality should be set at the lossy level. pretty notable difference with lossless. Whatever happened to setting and forgetting?
 

mrcond

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How do streaming Atmos mixes compare to the physical product (Blu Ray etc)? Do they lose anything or are they virtually identical?
The mixes are the same but it can be argued that some of the fidelity is lost with streaming, as opposed to lossless blu-ray tracks. To me, the differences are subtle but noticeable, primarily in a loss of definition.
 

mkt

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The mixes are the same but it can be argued that some of the fidelity is lost with streaming, as opposed to lossless blu-ray tracks. To me, the differences are subtle but noticeable, primarily in a loss of definition.
Do you have a favorite example where the differences are clearest to you?
 
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