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    Do Immersive Audio Mixes Sound Better?

     

     

    I fully understand the adjective "better" is subjective, and the question in the title requires a followup question. Better, compared to what? I use the word "better" to mean a sound that I, and likely most of us who like great sound quality, would consider better. Usually this means a recording that isn't dynamically squashed, among other somewhat illusive qualities. My comparison is between the traditional stereo versions and the immersive / Atmos versions of several albums. 

     

    Why look into this? A couple reason. First, I noticed a significant difference between a couple Atmos mixes and the stereo mixes. I thought, perhaps there's more to this immersive audio thing than just more channels. Second, it's not lost on me that an Atmos system is a fairly large commitment both financially and with respect to space. My goal here is to provide members of the Audiophile Style community with information. 

     

    Note: As part of this, I'll also show how much information is in the Atmos height channels. This obviously varies recording to recording, but based on my research, I've found that music uses more of the channels more often than movies.


    Let's dig into this one and take a look at what I've found.

     

    I first noticed something was up because of the large difference in volume between Apple Music Atmos content and "everything" else. This is talked about around the internet, with most people not understanding that it's actually a good thing. Apple places strict requirements on Atmos content created for its streaming service. The requirement that everyone audibly notices immediately is described by Apple below.


    "The loudness level of a Dolby Atmos mix must be at or below –18 LUFS (Loudness Units relative to Full Scale) in order to play back correctly on a system or device compatible with Dolby Atmos."

     


    In addition to Apple, music distributors such as CD Baby, also list similar requirements. 

     

    • For your release to be branded “Dolby Masters” on Apple the immersive source audio must meet the following requirements:
    • The Dolby Atmos master file must be provided as a BWF ADM file using 24fps timecode for all tracks.
    • All audio must be 24-bit LPCM audio at 48kHz.
    • All deliverables must be conformed and synced to the original stereo reference masters.
    • Target Loudness value should not exceed -18 LKFS measured as per ITU-R BS. 1770-4.
    • True-peak level should not exceed -1 dB TP measured as per ITU-R BS. 1770-4.
    • For albums where gapless playback is intended between tracks:
    • Each album track must be delivered as an individual BWF ADM file.
    • Each track boundary must be no more than half a frame (1,000 samples @ 48 kHz) earlier or later than the same track boundary in the corresponding stereo deliverable.
    • There must be no additional silence at the end of each track when compared to the same track from the corresponding stereo deliverable.
    • Please note that while ATMOS supports up to 128 channels per track, we can only facilitate submissions that do not exceed 25 GB in total size.

     

     

    Here are some examples, with objective data, showing that immersive Atmos audio mixes can be quite different from stereo mixes, but not always. Pearl Jam's latest album Gigaton was mixed to stereo and Atmos. The differences between the two are huge. It's like a completely different album. 


    This is the track named Alright, stereo 24 bit / 96 kHz, official lossless streaming and download stereo release.

     

    Dynamic Range (DR) = 7, Dynamic Range (R128) = 8.1 LU

     

    Pearl Jam Alright 2496 qobuz stereo.jpg

     

     

     

    Below is the same track, 24 bit / 44.1 kHz, official lossless Apple Music stereo release.

     

    Dynamic Range (DR) = 7, Dynamic Range (R128) = 7.9 LU

     

    Pearl Jam Alright 24441 stereo apple music.jpg

     

     

     

    The above two versions of the track look nearly identical. Now for the interesting part. Below is the 24 bit / 48 kHz, official Apple Music Atmos release, streamed in the Dolby Digital Plus codec. This is 7.1.4, but could also be played on any number of Atmos systems because the technology is adaptive (2.0, 5.1.2, 9.1.6, etc...)

     

    The top two (of 12) waveforms are the left and right channels. It doesn't take an audio engineer to notice that these look like completely different tracks. The Atmos version has absolutely no clipping, and leaves plenty of breathing room for the audio. Given the huge difference in dynamic range, I checked to see if all the Atmos channels had an impact that skewed the results. After removing all channels of the Atmos mix except the front left and right, the dynamic range of this actually increased (13 (DR), 14.1 LU (R128)).

     

    Dynamic Range (DR) = 13, Dynamic Range (R128) = 12.0 LU

     

    Pearl Jam Alright 2448 7.1.4 atmos apple music.jpg

     

     

     

    Taking this a step further, meaning better, I looked at Moby's album Reprise. The better part of this is that I have the lossless TrueHD Atmos version to compare to the Apple Music version, as well as stereo. Is Apple Music making Atmos better or are Atmos versions outside Apple Music as good or better? Of course it all depends on the album, but in this case, it appears that Moby released the same version to Apple Music as he released on Blu-ray. The Blu-ray being lossless TrueHD as opposed to Dolby Digital Plus.

     

    Let's look at five versions of the track named Everloving.


    Below is the stereo 24 bit / 48 kHz, official lossless streaming and download stereo release. You can see clipping toward the end of the track, and the dynamic range compression pushes the music beyond the point of no return. 

     

    Dynamic Range (DR) = 7, Dynamic Range (R128) = 14.2 LU.

     

    moby everloving reprise 2448 qobuz stereo.jpg

     

     

     

    Below is the 24 bit / 48 kHz, official lossless TrueHD Dolby Atmos Blu-ray release in a 7.1.4 channel configuration. You can see breathing room in the same location of the track, looking at the top two channels (left channel on top and right channel below that). 

     

    Also note the information in the Atmos height channels. Atmos channels are the bottom four channels in the screenshot. Traditional multichannel is incapable of reproducing this information. You can see that each of the four height channels contains slightly different audio. This is because of how Atmos is mixed as objects in a 3D space rather than channels. It isn't possible to take a stereo track and up-mix it for Atoms, similar to how some high resolution albums are created by simply converting CD to a higher sampling rate. 

     

    Dynamic Range (DR) = 12, Dynamic Range (R128) = 13.2 LU.

     

    moby everloving reprise 2448 7.1.4 atmos truehd.jpg

     

     


    Below is the 24 bit / 48 kHz, official lossless TrueHD multichannel 7.1 Blu-ray release (non-Atmos). The only difference is the lack of height channels that are present in the Atmos version. 

     

    Dynamic Range (DR) = 12, Dynamic Range (R128) = 13.2 LU.

     

    moby everloving reprise 2448 7.1 truehd multichannel.jpg

     

     

     

    What about the 24 bit / 48 kHz, official lossless TrueHD Atmos stereo mix from Blu-ray? Here you go. Even the Atmos stereo mix is much better than the non-Atmos stereo mix. The DR(128) of this Atmos stereo mix is slightly better than the 7.1.4 mix.

     

    Dynamic Range (DR) = 12, Dynamic Range (R128) = 15.2 LU.

     

    moby everloving reprise 2448 2.0 atmos truehd.jpg

     

     

     

    Below is the 24 bit / 48 kHz, official Apple Music Atmos release, streamed in the Dolby Digital Plus codec. This is 7.1.4, but could also be played on any number of Atmos systems because the technology is adaptive (2.0, 5.1.2, 9.1.6, etc...).

     

    This mix appears to be the same as the official lossless Atmos 7.1.4 mix released on Blu-ray. Cheers to Moby for creating a great album that also sounds great. 

     

    Dynamic Range (DR) = 12, Dynamic Range (R128) = 13.6 LU


    moby everloving reprise 2448 7.1.4 apple music atmos.jpg 

     

     

     

    Looking at Bruce Springsteen's Western Stars, songs from the film, we can see something a bit different. The lossless TrueHD Atmos 7.1.4 mix of Hitch Hikin' has greater DR, but significant less DR128. Looking at the waveforms shows us more breathing room for the Atmos mix and major use of the center channel. The front left and right channels look like a different song altogether. The surround channels are also used significantly, while the LFE channel (4th from top) is nearly empty.


    This is the track named Hitch Hikin', stereo 24 bit / 96 kHz, official lossless streaming and download stereo release.

     

    Dynamic Range (DR) = 9, Dynamic Range (R128) = 10.8 LU.

     

    Springsteen Hitch Hikin 2496 Qobuz Stereo.jpg

     

     

     

    Below is the 24 bit / 48 kHz, official lossless TrueHD Dolby Atmos Blu-ray release in a 7.1.4 channel configuration.

     

    Dynamic Range (DR) = 12, Dynamic Range (R128) = 6.5 LU. 


    Springsteen Hitch Hikin 2448 7.1.4 truehd atmos.jpg 

     

     

     

    Wrap Up

     

    Over the years, we've all played several formats of our favorite albums. The format in and of itself, isn't indicative of sound quality. With Dolby Atmos, it's the same as it ever was. Atmos can surely be used for terrible sounding albums. However, given Apple's -18 LUFS requirement to upload Atmos content, the fact that Atmos mixes must be created with original unmixed tracks (not up-mixed from stereo), and my limited research into sound differences between stereo and Atmos mixes, I'd say we are off to a great start with immersive audio and Atmos. 

     

    If more albums are mixed like Pearl Jam's Gigaton, Atmos could be THE audiophile format of the future. Breathing room, waveforms that don't clip, and large increases in dynamic range usually equate to better sound. I can't wait to continue digging into Atmos / immersive audio and listening to more of my favorite music.

     

     

     




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    Chris, great info.  Could you show also in comparison a traditional SACD-based stereo and multichannel track?  JCR 

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    27 minutes ago, jrobbins50 said:

    Chris, great info.  Could you show also in comparison a traditional SACD-based stereo and multichannel track?  JCR 

    Here are the numbers for Wish You Were Here, DSD Stereo, DSD 5.1, and 5.1 PCM 24/96.

     

    Screen Shot 2022-04-14 at 11.53.17 AM.png

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    Great article. Thanks as always. I forwarded the article to my local dealer, Dennis Penner at American Hi-Fi in Winnipeg, Manitoba, Canada and he provided the following feedback as he has been playing around with this quite a bit on his store's Lyngdorf demo system:

     

    In the process, they have created a problem.

    If you have been listening to Atmos at -18 at a high level, you will be blown out of the room when you switch to non-Atmos tracks - many of which are pushed to 0 and higher and are clipped as seen in the article - very annoying. 

    The other problem I have noted - not ALL Atmos labelled tracks are at -18 so they come blasting in as well.

    Apple needs to make all tracks be submitted at -18 - with 24 bit submissions there is lots dynamic range available so no reason to push the record level to the very top.

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    1 minute ago, ecwl said:

    Great article. Thanks as always. I forwarded the article to my local dealer, Dennis Penner at American Hi-Fi in Winnipeg, Manitoba, Canada and he provided the following feedback as he has been playing around with this quite a bit on his store's Lyngdorf demo system:

     

    In the process, they have created a problem.

    If you have been listening to Atmos at -18 at a high level, you will be blown out of the room when you switch to non-Atmos tracks - many of which are pushed to 0 and higher and are clipped as seen in the article - very annoying. 

    The other problem I have noted - not ALL Atmos labelled tracks are at -18 so they come blasting in as well.

    Apple needs to make all tracks be submitted at -18 - with 24 bit submissions there is lots dynamic range available so no reason to push the record level to the very top.

    Hi @ecwl thanks for the kind words. 

     

    I certainly hear what Dennis is saying. It's the age old issue or many recordings being WAY TOO LOUD :~)

     

    I haven't found an Apple Music Atmos track yet that isn't at -18, but I don't doubt some have snuck by the gatekeepers. 

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    Have you tried any recordings from Dr. Mark Waldrep? He has been doing this for years and believes this is the way music will go.

     

    https://www.aixrecords.com/

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    @ecwl check this out. Lynyrd Skynyrd's album Pronounced ... contains both Atmos and stereo tracks. The Atmos tracks are -18, the stereo tracks are not. Playing this album as a whole, not only switches between Atmos and stereo, but between loud and normal. Come on Apple!

     

    Screen Shot 2022-04-14 at 3.52.58 PM.png

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    Thanks for this! I have found that well-mixed Atmos releases, when rendered in 5.1*, provide much greater detail and depth than stereo mixes, and aside from the touted "immersion," it's just much easier for my ears to focus clearly on the various elements in the mix. This makes critical listening less fatiguing and more enjoyable.

     

    NB - Apple recommends enabling Sound Check to balance the overall loudness between tracks, and they specifically recommend this to deal with the difference in loudness between Atmos and stereo mixes. The only problem with that for some of the readers of this website is that HQPlayer's apodizing filters aren't likely to work properly on tracks that have their volume reduced by Sound Check (e.g., if you're using a digital loopback interface to feed HQPlayer from Apple Music). Not a problem for properly engineered material with the Apple Digital Master stamp of approval, but something to bear in mind.

     

    It's also worth noting that Atmos can be rendered to quadrophonic surround on the Mac, which can be a much more space- and cost-effective surround solution, and it still sounds very good. It's easy enough to set up in Audio MIDI Setup (AMS) with sound interfaces that have four outputs, or with an aggregate device that combines two stereo outputs. In my experience, it can be good for small spaces with near field speakers. I use this for a secondary listening setup, in my office.

     

    *Because I don't have an actual Atmos decoder, I listen to Atmos mixes in 5.1 either via Apple TV (into a DeckLink Recorder with Media Express -> Rogue Amoeba Loopback -> Digiface USB that feeds 3 stereo DACs), or on the Mac under Big Sur, directly out to the Digiface USB. In theory, I could create an aggregate device with more channels in AMS under Monterey, but last I checked, it wasn't actually rendering out from the built-in apps like TV or Music. I actually filed a bug report with Apple about this, but haven't checked recently to see whether it was fixed or not.

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    16 minutes ago, wisechoice said:

    Thanks for this! I have found that well-mixed Atmos releases, when rendered in 5.1*, provide much greater detail and depth than stereo mixes, and aside from the touted "immersion," it's just much easier for my ears to focus clearly on the various elements in the mix. This makes critical listening less fatiguing and more enjoyable.

     

    NB - Apple recommends enabling Sound Check to balance the overall loudness between tracks, and they specifically recommend this to deal with the difference in loudness between Atmos and stereo mixes. The only problem with that for some of the readers of this website is that HQPlayer's apodizing filters aren't likely to work properly on tracks that have their volume reduced by Sound Check (e.g., if you're using a digital loopback interface to feed HQPlayer from Apple Music). Not a problem for properly engineered material with the Apple Digital Master stamp of approval, but something to bear in mind.

     

    It's also worth noting that Atmos can be rendered to quadrophonic surround on the Mac, which can be a much more space- and cost-effective surround solution, and it still sounds very good. It's easy enough to set up in Audio MIDI Setup (AMS) with sound interfaces that have four outputs, or with an aggregate device that combines two stereo outputs. In my experience, it can be good for small spaces with near field speakers. I use this for a secondary listening setup, in my office.

     

    *Because I don't have an actual Atmos decoder, I listen to Atmos mixes in 5.1 either via Apple TV (into a DeckLink Recorder with Media Express -> Rogue Amoeba Loopback -> Digiface USB that feeds 3 stereo DACs), or on the Mac under Big Sur, directly out to the Digiface USB. In theory, I could create an aggregate device with more channels in AMS under Monterey, but last I checked, it wasn't actually rendering out from the built-in apps like TV or Music. I actually filed a bug report with Apple about this, but haven't checked recently to see whether it was fixed or not.

    If you create an aggregate device and configure it for 7.1.4, Apple Music will play it perfectly at 7.1.4. 

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    What version of macOS are you running, and on which hardware? I just upgraded to the latest version of Monterey (12.3.1) on my M1 Mini, and now even 5.1 is broken with Apple Music, both directly through the Digiface and via an aggregate device. Neither of the Atmos speaker configurations work, either. However, AppleTV works in 5.1 (but not 5.1.4 or 7.1.4). I wonder whether this is a bug that was introduced with the new native Apple Music application. All programs can output to 5.1 for me, but no higher, under Big Sur.

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    22 minutes ago, wisechoice said:

    5.1 is broken with Apple Music, both directly through the Digiface and via an aggregate device.

    I saw RME has an update for Digiface USB, worth a try? (2022 04 04)

    2000067998_Image2022-4-15at7_11PM.thumb.jpg.a1b47ca16c6842bcef3d9fbe7daa0d8f.jpg

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    Thanks, I didn't notice that. I will give it a try, although I will note that the same behaviour is exhibited with an aggregate device consisting of the built-in speakers and my display speakers. And surround works as expected (for 5.1) with the TV app, including with the Digiface USB. So it seems pretty likely that this is a bug in the Music app (and in all the built-in consumer apps when it comes to anything above 5.1).

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    Actually, the firmware for Digiface USB contained in that update isn't new, it's version 18, which I have already. It was a good thought, though!

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    6 minutes ago, wisechoice said:

    And surround works as expected (for 5.1) with the TV app, including with the Digiface USB.

    Curious about your settings of Audio MIDI Setup, would you post the screenshot of the aggregate device? 

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    3 minutes ago, El Guapo said:

    Curious about your settings of Audio MIDI Setup, would you post the screenshot of the aggregate device? 

    Sure, here's the quadrophonic setup. There's an additional bug in AMS, where channel 3 is mislabelled channel 1 in the pop-up menu. Buggy buggy!1984934025_ScreenShot2022-04-15at7_48_46AM.thumb.png.8f1b34af263466e3c15442be1956c932.png993423723_ScreenShot2022-04-15at7_48_00AM.thumb.png.e14545e0907fecde1e201ecce4875468.png1766574909_ScreenShot2022-04-15at7_47_49AM.png.1d3477efcd36b646a2b55a34383a5b2c.png

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    15 minutes ago, wisechoice said:

    an additional bug in AMS, where channel 3 is mislabelled channel 1 in the pop-up menu

    It's not mislabeled (also not a bug). You (or someone) put "1" into ch3 so the label becomes 1.😆

    1766574909_ScreenShot2022-04-15at7_47_49AM.png.1d3477efcd36b646a2b55a34383a5b2c.jpeg.7d040a47750dffba6d43f17d332efc91.jpeg

    You can edit the channel label as you like.

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    I most definitely didn't put it there. It was a fresh install of the OS. And you'll notice at the top of the window, "Stream 2 has 2 channels (3-4)" 🤔

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    But you're right that it uses those labels for the selection in the pop-up menu, and in principle they can be edited. Though depending on the order the devices are added, I'm finding that sometimes one or two channels can't be re-labelled on these devices. It's a bit random.

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    But I didn't even know they could be edited, so it definitely wasn't me. And the same pre-filled label for that channel, and that channel alone, was there when I booted back into Big Sur. Definitely a bug of some kind. I appreciate knowing about the labels, though! Thanks :-)

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    @wisechoiceHere's what I found: if you want to use Quadraphonic, CoreAudio default is ch1, 2, 5 and 6. You can't change this in AMS (AMS is just an organizer). If you connect 2 DACs and want to set as Quadraphonic, you'll prob never hear sound comes out from the DAC which designated to ch3 and 4.

    In this case, I'd suggest using Loopback to route the channel to the correct output.

    1902667567_Image2022-4-15at8_29PM.thumb.jpg.2ed3a5834edd959113ee4870651e0f9b.jpg

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    OK, I think I finally cracked the case. Dolby Atmos now has to be set to "automatic" instead of "always on" in Music. Then I'm able to get more than six channels from the Music app to either the Digiface or Blackhole 16ch. Not very logical, and not how it used to behave!

     

    As for quadrophonic, it always worked for me with an aggregate device, or equally to a four channel sound interface. And it seems to work with the same aggregate device, now that I've changed the setting to automatic.

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    5 minutes ago, bbosler said:

     

    sorry, that ship has sailed for both of us

    IMG_3820.webp

    IMG_3649.jpg

    Too funny!

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    Lol. Yes, well I suppose those settings weren't top of mind since you were chasing that TrueHD sauce.

     

    Now I just need to figure out how to mount these speakers without causing undue domestic strife.

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