‘Gravity’ Blu-ray Audio Comparison: 5.1 vs. Dolby Atmos

Since the inception of Dolby Atmos for the home, many home theater enthusiasts have debated the need and virtues of upgrading their current A/V receivers, questioning the new format’s effectiveness compared to traditional 5.1 or 7.1 surround sound. Warner Bros.’ new Diamond Luxe Edition of ‘Gravity’ provides our first opportunity to make a direct head-to-head comparison between a Dolby Atmos soundtrack and a dedicated 5.1 mix (found on the older Blu-ray release) for the same movie. The differences between them are enlightening.

Since making the Atmos upgrade myself a few months back, I can honestly say it was very worthwhile and sounds fantastic in my home. For me at least, the bigger issue is finding enough Blu-ray titles that capably demonstrate the awesome multidimensional experience of this object-based surround sound technology. Currently, there are eight Atmos Blu-ray discs available, and the desire to purchase any of them, of course, varies with the viewer’s taste. Personally, half of them are movies I’m not rushing to see, let alone buy, but since the selection is so small at the moment, I own all but two. ‘Unbroken‘ isn’t on my radar anytime soon, and ‘Step Up All In‘ is not my cup of tea and will not likely ever be watched. Unless tasked with providing coverage, I’m honestly okay without ever owning either of those. Instead, my eyes – or rather, my ears – have patiently waited for the arrival of Alfonso Cuarón’s ‘Gravity’ since it was announced in November that the double-dip special edition would feature a Dolby Atmos soundtrack. Speaking for myself, I’ve been in anxious anticipation to hear it.

With the Diamond Luxe Edition, Warner Bros. has reissued the award-winning sci-fi thriller as a two-disc package inside an attractive gatefold NEO Pack case. Each thick, hardy panel has a nice shiny, reflective surface like a piece of glass, and the two region-free BD50 discs sit comfortably on opposite panels with a small lip to hold them in place. It’s a beautiful package, but of course I’m not here to write about that. Instead, I want to compare the last year’s Blu-ray 3D release of the movie, which had a DTS-HD Master Audio 5.1 soundtrack, to this new Dolby Atmos mix with a TrueHD 7.1 core. Initially, I expected the differences to range from minor to a slight improvement at best. I especially wanted to use and compare the Dolby Surround Upmixer (DSU) feature in my receiver, since I’ve found that it does a surprisingly satisfying job of matrixing standard 5.1 and 7.1 soundtracks to my overhead speakers.


First, I should explain the excitement and ballyhoo of hearing ‘Gravity’ in lossless audio. Simply put, it’s DAMN good. In fact, it’s one of the best sound design mixes created in years. The praise and accolades for it are warranted. The people who worked on the mixing and editing did a phenomenal job with the story set in space, where there is no sound. Silence is effectively used for creating edge-of-your-seat suspense, but when sound does occur, it’s very selective and intentionally located, as demonstrated when the voices of the cast move in all directions at the film’s start. With the beautifully haunting, organic and ethereal music of Steven Price, we also have a score that pulls audiences into heart-pounding tension.

There’s a genuine excitement to hear and appreciate all this on Blu-ray, even in its DTS-HD Master Audio 5.1 configuration with DSU implemented, but the chance to listen in Dolby Atmos is twice as exciting. After spending some with both tracks, going back and forth between them and comparing individual scenes, I’m shocked to say that there’s a significant, night-and-day difference, and that the Atmos version decidedly wins hands-down. It offers one of the most immersive audio experiences of recent memory, and is easily a top demo choice for any home theater. Most notable is Price’s score. Where before his mesmerizing music only lightly bled to the speakers above, it now fills the entire room with an absorbing dome-like effect. One of the more jaw-dropping segments is the destruction of the International Space Station. Despite the lack of sound effects, specific musical effects whizz overhead to keep viewers on the edge as other aspects of the orchestration engulf the listening area with stunning clarity.

If Price’s score isn’t enough to convince high-def enthusiasts of Atmos’ virtue in the home, the rest of the outstanding soundtrack should definitely do the trick. The film’s first ten minutes deliver one of the coolest uses of surround speakers with various voices moving about everywhere. The 5.1 mix will please most, but that same movement around the room is nowhere near as convincing as it is in Atmos. This is most apparent between 4:05 and 4:40 as George Clooney plays a country tune and circles around the room. Even with DSU engaged, the music only lightly glides to the back of the room, but suddenly jumps to the right before appearing again in the front. However, in Atmos, the song smoothly floats from the left side to back overhead, to above in the right, before the character drops into view in the top right corner. All the while, Ed Harris’s voice also travels from the front left to above the listening area as the camera tilts to close-in on Sandra Bullock. In 5.1, Harris is only heard in the front left and simply moves to the center.


The use of voices in the film is rather ingenious because their diegetic movement is meant to emulate what Bullock’s character hears. This effectively creates for viewers the feeling of wearing a helmet like she does. One of the more impressive moments is when Mission Control orders the STS-157 crew to abort the mission due to the oncoming debris, starting at the 9:50 mark. DSU does fine during this four-minute sequence as the worried voices of Harris and Clooney pan from front to back and bounce off the sides. Still, the Atmos track bests it as those same voices convincingly fill the space above the listener’s head. Then, Clooney’s voice flawlessly swings across the back of the room to the front as Bullock somersaults into space. Almost immediately after, when Bullock starts breathing again at around 14:20, the camera slowly pushes in on her face, breaking through the helmet’s glass, and her anxious breathing is heard from above mixed with various static noises. Meanwhile, the 5.1 mix place these same sounds in the lower front soundstage.

Remarkably, this is only the beginning of the movie. Looking at my notes, I found a few noteworthy segments with DSU on, whereas in Atmos I made a long list of time codes I could spend more time gushing over.

I’ll quickly run through a few scenes where Atmos is a big improvement over its predecessor, starting at around 33 minutes when Kowalski instructs Ryan to enter the ISS. When she finally does (38:10) and removes her garments, they bounce all around the airlock. The fire eruption inside the ISS sequence (44:20) sounds as if it engulfs the room, and while inside the Soyuz (44:53 – 46:10), various loud, crashing explosions slam overhead. Later (55:15), Ryan pushes buttons right above the listening area. During her race to the Shenzhou capsule inside the Chinese space station (1:13:30), various noises surround the viewer and continue with several bumps and rattles (1:15:55), creating an awesome dome-like soundfield. The whole thing finally finishes when Ryan emerges from the water (1:21:15) with the lifelike sounds of local wildlife and a fly buzzing in the air above.

Needless to say, I was incredibly mesmerized and taken aback by the Dolby Atmos mix of ‘Gravity’. It’s not only a significant improvement over its DTS-HD MA 5.1 alternative, but it’s a surprisingly better demonstration of the new audio format than the ridiculously bombastic and obnoxiously loud ‘Transformers: Age of Extinction‘ or ‘Teenage Mutant Ninja Turtles‘.

DSU upmixing of the 5.1 version is a competent enough effort with many good moments where the front and rear heights deliver pleasing effects, but after spending a couple days toggling back and forth, it honestly doesn’t compare to the discrete directionality of the Atmos soundtrack, which creates a satisfyingly believable dome-like soundfield. Whereas effects tend to be localized in the 5.1 track, atmospherics seem unbounded and ubiquitous in this new object-based sound format as objects move within a realistic and broad space. ‘Gravity’ in Dolby Atmos has become my new go-to demo disc.


  1. This is a great article, E., but it just makes me all the more disappointed that Warner couldn’t be bothered to include the 3D version of the movie with Atmos as well.

      • William Henley

        I wonder if DVD Fab will support ripping of the raw audio track. Then you could rip the atmos track from this disc, rip the video from the 3D Blu-Ray in Full Side-by-Side, and remux the file. In fact, I wouldn’t be surprised if someone has already done this. However, I don’t have DVD Fab in front of me, and do not remember if it allows ripping of Audio without reencoding. From their website:
        Audio: MP3, MP4, M4A, WMA, WAV, AAC, AC3, DTS, etc.

        Even if it did rip the Atmos track, you would then need a software player that could pass the audio through to your reciever.

        However, Gravity is a big enough movie that I could see software developers scrambling to add Atmos support simply for this movie. So if DVD Fab and VLC both add Atmos support, then it would be easy to rip the audio from the Atmos disc and mux it together with the 3D video.

        • William Henley

          Simple Google search says that DVDFab does support Audio copy, and WILL rip Atmos tracks, but most software players cannot handle the audio. So we just need Atmos support added to video players.


          VLC is adding Atmos support, MPC-HC already has it (added in version 1.7.7 – read the 1.7.7 changelog):


          So, this means right now, you can have Gravity in 3D with Atmos.

          Step 1 – Rip video from 3D Blu-Ray with DVD Fab
          Step 2 – Rip Audio from Atmos disc with DVD Fab with Direct Stream copy
          Step 3 – Mux together with MakeMKV
          Step 4 – Playback with MPC-HC

          So does someone want to try this and report the results?

          • Allan

            I did exactly this:

            * Found a copy of the Dolby Atmos versions sound track (someone shared just the audio, you could get the whole thing and rip out the Audio using MKVExtract).
            * Merged the 3D Video Stream with the Atmos audio stream.
            * Done.

            I did the same thing to Frozen as you can choose 7.1 Audio with 2D or 5.1 Audio with 3D but not 7.1 Audio with 3D.

            Played it to my Atmos receiver hooked up to my HTPC and Atmos comes on, audio from everywhere.

          • Allan

            I use Kodi (XBMC) set to bitstream but it works pefectly using the CCCP Codec Pack and Media Player Classic as well.

  2. I’d like to echo these findings. The Dolby upmixer works fine. It’s generally complementary, but when you reach a point in an actual Atmos Mix where the mixer/sound designer dialed up the use of Atmos, the difference can be staggering. It makes you anxious to get more of the existing Atmos movie mixes out on Blu-ray.

  3. Jason Perkins

    A couple years ago I upgraded my theater screen to a 2.37:1 CIH which is visually, the best improvement I’ve ever made to my home theater. Last fall, I upgraded my audio to a 7.2.4 Atmos configuration and it’s sonically the best improvement I’ve ever made, besting my purchase of JTR speakers by a country mile.
    The three dimensional sound field that is created and enhanced by Atmos is astounding. The DSU upmixer is a revelation.
    I can’t wait to watch and listen to Gravity again, this time the way it was meant to be heard. 7 channel Dolby Atmos. Dig it!

  4. Pedram

    What’s your Atmos setup? On the gear page it still says you have a “Marantz SR6006 7.2 A/V receiver “.

  5. David Batarseh

    Recently purchased a Denon AVR-S910W for atmos and I cant find the Dolby Surround Upmixer (DSU) option. Any idea if my receiver supports this, thanks.

    • If the receiver is an Atmos model (which the AVR-S910W appears to be), it automatically comes with DSU. Denon has discontinued Dolby ProLogic in the Atmos models and replaced it with DSU.

      Assuming that this model works the same as my AVR-X5200W, it should have “Sound Mode” buttons on the remote for Movie, Music, Game and Pure. On mine, they’re colored green, red, blue and yellow. Hitting the Movie button will bring up a menu. Scroll to the “Dolby Surround” option and you’ve turned it on.

      Annoyingly, the X5200 defaults out of the box to leaving DSU off for every sound format, and makes you manually turn it on the first time any new sound format is received (once for Dolby Digital, once for Dolby TrueHD, once for DTS, once for DTS-HD MA, once for PCM, etc.). If you forget to do this, DSU remains off. However, after you’ve done it once for each sound type, it should remember that for the future. I don’t know whether your model works the same or if Denon fixed that.

  6. David Batarseh

    You are the man! Thank you so much; spent hours searching forums with no mention of this option; but you were dead on! Hope when DTS X rolls out, they have a similar options. For now, The Dark Knight sounds amazing with the DSU applied and makes my loss of 7.1 a little easier.

    • I should mention that Denon’s 2015 model receivers have a programming error that doesn’t allow DSU to be used with DTS codecs. (The older 2014 models were not affected.) Because the Blu-ray for The Dark Knight uses Dolby TrueHD, DSU can be activated. However, if you try to watch The Dark Knight Rises, which has DTS-HD Master Audio, DSU is disabled.

      The workaround for this is to switch your Blu-ray player to decode the audio internally and output as PCM through HDMI. However, you’ll need to remember to switch back to Bitstream whenever you want to watch a disc with a native Atmos soundtrack. (Atmos can only be transmitted as bitstream.)

      The hope is that Denon will be able to fix this when the firmware upgrade that adds DTS:X becomes available.

      • Tony Bouchard

        I wonder the behavior of the Dolby upmixer on 2015 Denon receivers is intentional and won’t be corrected? It seems like the intention is that we use DTS Neural:X with DTS HD titles and DSU with Dolby True HD titles. It’s not ideal that they haven’t released the DTS:X update yet, but the workaround isn’t too bad.

        • Denon has not made an official statement on the matter, but what I’ve heard is that this is an error that they intend to fix, not a deliberate business decision. However, getting DTS:X and DTS Neural:X working has taken top priority.

  7. Brett Cameron

    Was a comparison done of the 7.1 core of the Atmos track via the DSU compared to the Atmos track?
    I would be interested in hearing those differences.

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