Now That Atmos Is Everywhere… Real vs. Phantom Center in a 5.1 Music-Focused Setup

[Sal1950]

It probably will, Sal, it probably will. But it might not be the same price. And then the point of it comes into question, are you just lining the pockets of the middlemen for no perceptual reward?

Could be, but I remember when brussel sprouts were $0.19 cents a pound.

I note that AC4 lossy codecs are now out, that halve the bitrate for the same quality. So, without changing to lossless or increasing their Atmos bitrate above 768 kbps, Apple could deliver audio quality comparable to 1500+ kbps AC3 audio. The 'odd moments' of perceptual differences would be very rare indeed.

All kidding aside, I thought that tiered music streaming was all but gone. I know Apple Music only has the single level, "Student for $5.99/month, Individual for $10.99/month, and Family for $16.99/month." That includes everything in their catalog including 5.1 and Atmos.
Marketing will rule eventually, it only took a few months after the first 2ch streamer went lossless before most of the rest fell in line. Only Spotify kept their customers dangling with 4 years of promises.
Video is a whole screwy world of it's own. LOL

 

[Fidji]

I can only speak for myself, but I would prefer some evidence that there's an audible difference between lossy and lossless before making demands that streaming services spend additional bandwidth (which is not an infinite resource).

I've been unable to find any believable tests of this. Can you refer me to any ABX or other blinded tests that show this difference?

It's been shown repeatedly and conclusively that sighted tests are not valid.

And, since the real issue to which I was responding is the complaints of using lossy codecs for Atmos streaming, perhaps those complainants can post some valid (academic or other) evidence of the audible problem. Then we are dealing with the initial claim, and its veracity.

As a footnote and baseline, modern codecs seem to have an audible quality loss once they get below 64 kbps per channel. An example. IMO if we can't tell that the quality is less, we shouldn't care that much about it.

cheers

Do Atmos Codecs Really Matter? Pro Engineers Compare AC-4, DD+ and PCM | Audio Production: News, Tutorials & Reviews

Most Atmos listeners never hear the studio master, only a compressed delivery codec. So how big is the difference in practice? The team at Immersive Machines hosted a double-blind 7.1.4 listening test with pro engineers comparing DD+, AC-4 and lossless PCM. The results were closer, and more revealin

www.production-expert.com

”When I first listened to new albums on Apple Music or TIDAL on my living room home theater system, DD+JOC was exciting and filled the room with a big sound in a way that stereo simply could not do. But over time, the limitations of DD+JOC became more apparent. And when listening to DD+JOC in the more critical setting of a professional mix room, and with an uncompressed reference available for comparison, its limitations are obvious. The spatial distinctiveness of individual objects are blurred and the soundstage folds in”.

What every listener with access to quality MCH system AND ability to critically listen to immersive audio was able to tell since years - that there is clear audible difference between DD+ and lossless Atmos, is now being slowly accepted - even if the only motive is to push new Dolby codec. I hope, we are going to see more tests like this [funded by Dolby ;-) ] as Dolby will push AC4 into streaming.

So the discussions should be really now about “How much do I care about MCH audio quality” rather than empty discussions about what should be audible or not. If you are not able to distinguish DD+ vs lossless Atmos - now you have the answer - either your critical listening ability is not good enough or the system was not good enough to show the differences [or both].

@Sal1950 - looks, like we will be getting even LOWER bit rates in the future ;-), as usual only reason is better quality for the end consumer.

 

[Chrispy]

Could be, but I remember when brussel sprouts were $0.19 cents a pound.

And overpriced then Yecch! Did just go look, still not too bad on a per pound basis with current currency

 

[Andysu]

Do Atmos Codecs Really Matter? Pro Engineers Compare AC-4, DD+ and PCM | Audio Production: News, Tutorials & Reviews

Most Atmos listeners never hear the studio master, only a compressed delivery codec. So how big is the difference in practice? The team at Immersive Machines hosted a double-blind 7.1.4 listening test with pro engineers comparing DD+, AC-4 and lossless PCM. The results were closer, and more revealin

www.production-expert.com

”When I first listened to new albums on Apple Music or TIDAL on my living room home theater system, DD+JOC was exciting and filled the room with a big sound in a way that stereo simply could not do. But over time, the limitations of DD+JOC became more apparent. And when listening to DD+JOC in the more critical setting of a professional mix room, and with an uncompressed reference available for comparison, its limitations are obvious. The spatial distinctiveness of individual objects are blurred and the soundstage folds in”.

What every listener with access to quality MCH system AND ability to critically listen to immersive audio was able to tell since years - that there is clear audible difference between DD+ and lossless Atmos, is now being slowly accepted - even if the only motive is to push new Dolby codec. I hope, we are going to see more tests like this [funded by Dolby ;-) ] as Dolby will push AC4 into streaming.

So the discussions should be really now about “How much do I care about MCH audio quality” rather than empty discussions about what should be audible or not. If you are not able to distinguish DD+ vs lossless Atmos - now you have the answer - either your critical listening ability is not good enough or the system was not good enough to show the differences [or both].

@Sal1950 - looks, like we will be getting even LOWER bit rates in the future ;-), as usual only reason is better quality for the end consumer.

atmos is near field audio junk enough said on these new rubbish fake 3d , umm , 2 1/2d is what it is , 15 years of dolby lab marketing lies

 

[kyuu]

So the discussions should be really now about “How much do I care about MCH audio quality” rather than empty discussions about what should be audible or not. If you are not able to distinguish DD+ vs lossless Atmos - now you have the answer - either your critical listening ability is not good enough or the system was not good enough to show the differences [or both].

Ah the old audiophile standby of "your ears are tin and/or your system isn't resolving enough". Totally convincing (not). Properly controlled listening tests or GTFO.

 

[Sal1950]

atmos is near field audio junk enough said on these new rubbish fake 3d , umm , 2 1/2d is what it is , 15 years of dolby lab marketing lies

Stereo, blah humbug, it's all a gimmick. All you really need is a good mono system.

 

[EJ3]

Stereo, blah humbug, it's all a gimmick. All you really need is a good mono system.

And if you want more: DUAL MONO!

 

[Fidji]

Ah the old audiophile standby of "your ears are tin and/or your system isn't resolving enough". Totally convincing (not). Properly controlled listening tests or GTFO.

yep, that is what was in the link. Controlled listening test hosted by AES.

No need to get emotional about cold hard truths of life. I think there is a scientific consensus that people differ in their abilities to discriminate audibility of some phenomena [hence usage of trained listeners in Harman] and also there is a consensus about he fact, that you need to meet certain minimum performance criteria for the system, in order to get any reasonable results out of the test. Third component is proper test recordings - some reveal more, some less, lot of them nothing at all.

What I do like about MCH is that the industry is very professional and data driven. So we have something like standards, etc, much more compared to 2Ch. There is CEDIA RP22 immersive audio performance overview, and I think it is reasonable to expect to see at least Lvl 2-3 systems in the discussion about audibility of lossless vs DD+. If a system does barely meet Lvl1 [“basic artistic intent”] then its owner does not need to worry about nuances between codecs and bitrates.

Has nothing to do with tin ears or whatever audiophile myths, just common sense.

 

[Matt S]

yep, that is what was in the link. Controlled listening test hosted by AES.

No need to get emotional about cold hard truths of life. I think there is a scientific consensus that people differ in their abilities to discriminate audibility of some phenomena [hence usage of trained listeners in Harman] and also there is a consensus about he fact, that you need to meet certain minimum performance criteria for the system, in order to get any reasonable results out of the test. Third component is proper test recordings - some reveal more, some less, lot of them nothing at all.

What I do like about MCH is that the industry is very professional and data driven. So we have something like standards, etc, much more compared to 2Ch. There is CEDIA RP22 immersive audio performance overview, and I think it is reasonable to expect to see at least Lvl 2-3 systems in the discussion about audibility of lossless vs DD+. If a system does barely meet Lvl1 [“basic artistic intent”] then its owner does not need to worry about nuances between codecs and bitrates.

Has nothing to do with tin ears or whatever audiophile myths, just common sense.

I do not think he is getting upset about cold hard truths. The article is interesting for sure and does point to the full fat file being the preference of those taking part.

I'm listening to multi-channel on a 4.1 system and switching back and forth between Apple Music vs Roon streaming mutli-channel from my server - its difficult to tell apart in my opinion. This is sighted - I know which is playing - though not obviously hearing height channels etc. Using Brothers in Arms 5.1 to compare - maybe full fat has the edge? Maybe.. both sound awesome to me.

System is HTx and Genelec all round - as revealing as it gets, pretty much.

Regardless, I maintain that the original production plays a much more key role in the final sound quality than anything else (assuming transparency from that point). I would rather listen to a compressed multi channel track that was well produced, than utter pants at a high bit rate.

 

[Matt S]

atmos is near field audio junk enough said on these new rubbish fake 3d , umm , 2 1/2d is what it is , 15 years of dolby lab marketing lies

... and yet to my ears, many multichannel versions are less fatiguing than that wonderful stereo gift of high resolution. High resolution of the same, LOUD recording made for radio/music on the move playback, through bog standard apple earphones included with every phone purchase a few years back. Wow.

 

[Fidji]

I do not think he is getting upset about cold hard truths. He asked for evidence.

I sincerely want to improve. Please can you give me some short feedback, how could I communicate more precisely the fact, that there was controlled blind listening test performed by audio professionals, hosted by AES and results were clearly showing, that there is audible difference between lossy DD+ and lossless Atmos?

I have attached direct link. If you click on it, you can even find out, what to listen for.

Thanks in advance.

 

[Fidji]

I'm listening to multi-channel on a 4.1 system and switching back and forth between Apple Music vs Roon streaming mutli-channel from my server - its difficult to tell apart in my opinion. This is sighted - I know which is playing - though not obviously hearing height channels etc. Using Brothers in Arms 5.1 to compare - maybe full fat has the edge? Maybe.. both sound awesome to me.

System is HTx and Genelec all round - as revealing as it gets, pretty much.

To be expected, 4.1 is not Atmos and with phantom center on top you it should be vary hard, if not impossible, to hear differences, as they are most pronounced in spatial resolution.

If you are into classical music - get yourself BR Audio of Carlos Kleiber DG recordings - and then compare it with what is on Apple Music. In lot of cases you can even see it, as FW are active in TrueHD and not in DD+.

 

[krabapple]

Do Atmos Codecs Really Matter? Pro Engineers Compare AC-4, DD+ and PCM | Audio Production: News, Tutorials & Reviews

Most Atmos listeners never hear the studio master, only a compressed delivery codec. So how big is the difference in practice? The team at Immersive Machines hosted a double-blind 7.1.4 listening test with pro engineers comparing DD+, AC-4 and lossless PCM. The results were closer, and more revealin

www.production-expert.com

”When I first listened to new albums on Apple Music or TIDAL on my living room home theater system, DD+JOC was exciting and filled the room with a big sound in a way that stereo simply could not do. But over time, the limitations of DD+JOC became more apparent. And when listening to DD+JOC in the more critical setting of a professional mix room, and with an uncompressed reference available for comparison, its limitations are obvious. The spatial distinctiveness of individual objects are blurred and the soundstage folds in”.

What every listener with access to quality MCH system AND ability to critically listen to immersive audio was able to tell since years - that there is clear audible difference between DD+ and lossless Atmos, is now being slowly accepted - even if the only motive is to push new Dolby codec. I hope, we are going to see more tests like this [funded by Dolby ;-) ] as Dolby will push AC4 into streaming.

So the discussions should be really now about “How much do I care about MCH audio quality” rather than empty discussions about what should be audible or not. If you are not able to distinguish DD+ vs lossless Atmos - now you have the answer - either your critical listening ability is not good enough or the system was not good enough to show the differences [or both].

@Sal1950 - looks, like we will be getting even LOWER bit rates in the future ;-), as usual only reason is better quality for the end consumer.

How excited I was to see a blind comparison of this!

And guess what it showed (again): differences are hard or impossible to hear when all channels are playing. 'Soloing' a channel makes artifacts much easier to hear.

Here are more relevant parts of the article, with my notes and emphases bolded.
First: How they did listened for atifacts:

1. Listen to all codecs with all speakers on. OK
2. Listen again with L/C/R off. kinda bullshit, psychoacoustically speaking
3. Listen a third time while solo’ing individual speakers (like Left Top Front, or Right Rear Surround, etc.). very much bullshit from a psychoacoustic persepctive

Excerpts from results:

I personally find that all three codecs playing compressed pop musc with all loudspeakers turned on in 7.1.4 sound pretty good. And when we look at the survey results of the question: “When listening with all of the loudspeakers ON, how noticeable were artifacts (gating, swishing, graininess, loss of spatial precision, loss of frequency range)?” …we see that compression artifacts were slightly more noticeable with DD+JOC compared to AC-4 or PCM. But when listeners had the opportunity to solo individual loudspeakers (removing the psychoacoustic masking), artifacts in DD+JOC became very noticeable, while being slightly noticeable in AC-4 and barely noticeable in the reference PCM *(of course, by definition there are no artifacts in the reference, and while some listeners confidently identified the total lack of artifacts in the reference PCM, other listeners were unsure, so the vote was split in an interesting way).

Rating the overall audio quality of each codec, the reference PCM was the strong preference, but only when listeners could solo loudspeakers. When listening in a conventional manner with all speakers on, the reference PCM and AC-4 were in a statistical dead heat. Very impressive. I would encourage anyone who does a similar comparison to remember that the vast majority of consumers can’t solo channels, and to not let the advertised bitrates bias your listening.

NB AC-4 is a newer lossy codec used for full Atmos listening (Tidal streaming already uses AC-4 IM for binaural headphone listening) . It has a lower bitrate than DD+JOC, the lossy codec used by Apple Music streaming for Atmos.

*LOL

//


'Soloing' to reveal artifacts is the same genre of stunt I've seen other pro audio guys pull before, when they should (and do) know better. Like when George Massenburg did his travelling 'mp3s suck' act years ago, where he would play people the *difference file* from subtracting the mp3 from the lossless version and say 'this what you are missing!'

tl;dr: The cold, hard truth is, psychoacoustic modelling for lossy encoding works.

 

[krabapple]

yep, that is what was in the link. Controlled listening test hosted by AES.

No need to get emotional about cold hard truths of life.

Indeed, you might want to read that whole article closely , with your warmest blankie handy.


(btw, as author properly admits, n=16 participants doesn't quite rise to scientific rigor-- as he phrases it, "Not large enough to be scientifically useful." Though we can appreciate the effort, which is all too rare.)

 

[kyuu]

I admit, as soon as the "tin-eared, unresolving system" junk was trotted out I didn't bother following through with the link. Still, krabapple already covered the issues there well-enough.

 

[Chromatischism]

I don't understand the contention.

If multiple listeners can hear artifacts, then artifacts are there.

No need to downplay that or complicate the issue with arguments of multiple speakers.

It's no different when testing speakers in mono instead of stereo, which is standard ASR protocol by Amir.

It is well-known that once you go stereo, it is harder to hear issues. This fact was made prominent by Toole and Olive at Harman.

Add a subwoofer, and it becomes that much harder.

If that is good enough for you, then stop reading speaker reviews on ASR and just buy something cheap.

 

[krabapple]

I don't understand the contention.

If multiple listeners can hear artifacts, then artifacts are there.

If they only hear them 'solo', then it doesn't matter when you're listening normally

No need to downplay that or complicate the issue with arguments of multiple speakers.

It's no different when testing speakers in mono instead of stereo, which is standard ASR protocol by Amir

It is well-known that once you go stereo, it is harder to hear issues. This fact was made prominent by Toole and Olive at Harman.

Add a subwoofer, and it becomes that much harder.

If that is good enough for you, then stop reading speaker reviews on ASR and just buy something cheap.

Speakers are not lossy compression codecs. So it is in fact different.

 

[Sal1950]

What I do like about MCH is that the industry is very professional and data driven. So we have something like standards, etc, much more compared to 2Ch.

There is also the point that a large number of the Multich-Atmos enthusiast mixing engineers are very anti-heavy compression. The majority of the releases come with a relatively high dynamic range avoiding brick wall filtering at all costs.

The cold, hard truth is, psychoacoustic modelling for lossy encoding works.

"For reference, B was AC-4 running at 448 kbps. And C was a 7.1.4-ch PCM render at 24-bit 48 kHz resolution, a data rate of 13,824 kbps. This is over thirty times the data rate of AC-4, and some of these expert listeners (including myself) were occasionally fooled into thinking there was no difference or only a small difference between AC-4 and PCM. That’s a huge achievement and I am eagerly looking forward to the large music streaming service that will adopt AC-4 and provide it to their customers."

A well done though limited in scope test. What bothers me is this wrap-up by those who are industry professionals. No one there made any claim that either of the 2 compression codes were totally inaudible, then instead of calling for a move to lossless, they are still willing to accept AC-4? All this is so reminiscent of 2ch streaming discussions from back a few years. The arguing over which provider used the least intrusive compression, who's was better, thousands stating they could here no differences, I myself admitted I couldn't readily hear Spotfy codec but yet lobbied for lossless.
But in the end streamer X offered lossless for a few bucks more, then streamer Y offered it a couple $ less, then streamer Z just brought it online for no extra $ at all. Then they all fell in line except for Spotify who dragged their a-ses for three more years. LOL
Bottom line to me is that as long as we willing accept a compromised steam, that's what well get.
I did sent a couple emails to Kaleidescape asking then to consider starting a "Audiophile Music" tier to their system. If I could listen to and download any album to my server and wouldn't have to purchase the BluRays any more, I wouldn't mind paying them a little more. I doubt it will ever happen, I'm sure they're aware of what happened in the 2ch world and the price war that became part of that world. Good for us, bad for them.

 

[Sal1950]

If they only hear them 'solo', then it doesn't matter when you're listening normally

I disagree, all it proved was that group of 12 listeners couldn't readily ID the problems with all channels playing.
Would you feel the same way about .00x distortion being focus listening audible with one channel playing but being masked with X number of channels active?

 

[kyuu]

This seems like the whole rigamarole with "but trained listeners can sometimes hear artifacts in high bitrate MP3s". Yeah, sure, we know that. So what? I have a large library of MP3s that range from 256kbps to 320kbps. Never when listening to those am I hearing artifacts. Could I hear them if I put on some headphones and really tried? Maybe. But I'm not analysing the music, I'm listening to it.

Now for music, a 16-bit 44.1kHz or 48kHz stereo FLAC is still low enough in data usage that I use it for streaming most of the time because, why not? Except when I'm on cellular data, then I have no issue going down to 320kbps (or even lower) MP3. More to the point, when you're doing 6+ channels for surround at the same time you're doing a 4k video stream, that's a lot of continuous traffic to be sending through the internet tubes. Expecting streaming services to send lossless surround sound is simply unrealistic. We're quite far from a post-bandwidth scarcity scenario regardless of where you are. And if we want to send more data, the video streams are in much more need of less compression than the audio.

So yeah, I don't much care about compressed Atmos from streaming services at this point. If I want lossless audio, I buy the content on disc (and yes I own quite a few).