Auro-3D® Immersive Sound Interview with Wilfried Van Baelen

While Dolby Atmos has dominated the headlines lately, we thought it would be a good idea to take a look at the competing next generation formats, namely Auro-3D®. If you don't know much about Auro Technologies, don't feel too bad: while they've been slowly building a name for themselves in the professional cinema scene, they're relatively unknown in the home audio market. That's due to change soon, as like Dolby, Auro is looking to bring their 3D sound format to the home market. To learn more about this we had a chat with Auro's founder, Wilfried Van Baelen:

Audioholics: Please explain what Auro-3D® Sound is.

Wilfried: Auro-3D is the “Immersive Sound” format that revolutionized the cinema industry with true 3D sound.  Auro-3D is also the first 3D sound format brought to home theaters, with the introduction of compatible A/V receivers in January 2014. Note that Auro-3D is not a conventional “Surround Sound” format but an “Immersive Sound” format. What’s the difference? Surround formats, like standard 5.1 and 7.1 are 2-dimensional formats using an auditory plane around the listener. They are not true 3D audio formats with X, Y, and Z dimensions to envelop the listener.

Surround sound was for many years marketed as 3D sound,  thus causing some confusion when I started talking about a new true 3D sound system about 10 years ago. Most people said something along the lines of, “I’ve had a 3D sound system at home for a few years, so what’s new?” When I introduced the Auro 9.1 and Auro 10.1 speaker layouts at the AES conventions in Europe and USA in 2006, the workshops were called “Surround sound with Height” to avoid confusion, but this terminology was impractical as a general term for true 3D sound. Therefore, when I officially launched the Auro-3D format in 2010 at the AES Spatial Convention in Tokyo, I came up with a new term: “Immersive Sound,” which means a hemispheric reproduction of sound all around the audience. Note that an “Immersive Sound” format is not inherently tied to the use of a channel- or object-based technology. Those are merely delivery formats. I would also note that using object-based technology doesn’t necessarily create a more immersive sound experience per definition; rather the opposite can be true (more about that later).

Auro 3D presents a "dome of sound" to the listener.

Auro-3D is all about a totally new sound experience that surpasses anything you’ve heard before. By fully immersing the listener in a cocoon of lifelike sound, Auro-3D creates the sensation of actually 'being there,” along with the best reproduction of color/timbre using the most efficient speaker layouts. The Auro-3D format is designed as a cross market solution with fully compatible and scalable speaker layouts based on the size of the room, and built on the specs of today’s 5.1 and 7.1 surround standards for professional cinema as well for home cinema. The groundbreaking Auro-Codec® technology is a key part of the Auro-3D format, and allows an easy integration in all audio markets (film, games, music, broadcast, etc.) without any need for changes in specs, bandwidth or delivery formats (existing Blu-Ray format etc.). This unique technology allows us to bring an “Immersive Sound” experience to all markets with high resolution audio in all channels.

During the Tokyo convention in 2010, I presented the Auro 11.1 cinematic system, which is based on the existing 5.1 surround standard. It uses a unique 3-layered speaker layout that allows for a much more natural vertical spread of sonic energy in the hemisphere, which is key to getting the most enveloping experience. World famous Skywalker Sound installed their first Auro-3D Studio System in MIX A Studio during the summer of 2011. A few months later, this was followed by the announcement that Lucas film was to release “Red Tails” as the first movie ever in “Immersive Sound” using the Auro-3D format. Barco, worldwide leader in professional cinema projectors and exclusive partner of Auro Technologies for Digital Cinema, was immediately selling Auro 11.1 systems on a global scale.

Audioholics: How is Auro-3D different or similar to Dolby Atmos® and DTS® UHD?

Wilfried: Really, there are many differences and only a few similarities. The more consumers understand those differences, the more they will understand that Auro-3D is the best solution for a cross market “Immersive Sound” format. One similarity is that Dolby and DTS both added “height around the listener”, after Auro-3D successfully launched this concept.  The recommendation of bass management for all surround and ceiling channels is another common positive advantage for the above formats, and helps achieve better coherence when moving objects from the screen into the theater. Another commonality is that each of the above are ‘hybrid formats,’ meaning they combine “object-based” and “channel-based” technology. Yes, Auro-3D uses object-based technology as well, but takes a different tact from Dolby Atmos and DTS UHD. Dolby Atmos focuses on a more object-based approach. However, since more than 90% of a mix is typically produced by the channels (even in an object-based mix), Auro-3D has chosen a channel-oriented approach which we feel has many other advantages, i.e. workflow, distribution, installation of systems, cost, as well as reproducing the most natural sounds with native recordings in 3D (not possible in object-based technology, which is an artificial way to reproduce true 3D sound). Dolby and Auro-3D have very specific speaker layouts in order to have an end-to-end solution to maximize the preservation of the artistic intent. DTS on the other hand claims that their MDA object-based technology is ‘speaker layout agnostic,’ which sounds very attractive to consumers. Unfortunately, this flexibility is also a challenge because small changes in speaker layout impact artistic choices made in the studio. The tolerances and scalability of speaker settings is much smaller than most people would believe, and cannot simply be adjusted by a renderer using object-based technology without affecting audio quality. So far, DTS does not have any content or hardware out yet. Conversely Atmos and Auro-3D already each have more than 500 installations worldwide, and abundant content is available in both formats.

The immersive experience
The biggest difference between our competitors and the Auro-3D format is in the quality of the immersive experience. The combination of audio quality (high resolution audio in all channels) and the unique Auro-3D speaker layouts allow us to deliver the most efficient immersive sound experience in all markets. Formats with only two Height speakers (like Atmos 5.1.2 with 2 side height speakers) can’t reproduce a full 3D soundscape: a simple fly-over is not possible because the plane would all land behind the listener in the lower surround speakers. You need at least a quadraphonic Height layer above a surround system. On the other hand, some people think that more speakers are always better and more immersive. However, every extra speaker beyond the minimum needed to create a 3D sound field (which depends on the size of the room and size of the sweet spot), will add issues in phasing, rendering, workflow, and cost. Moreover, the precise localization of sounds is absolutely not the most important aspect in an immersive experience. Scientific research has proven that the sound color is key in achieving a natural sound. For that reason has the Auro-3D format has chosen to deliver in all markets high resolution audio in each channel combined with a unique speaker layout that allows the most natural immersive sound experience.

Auro 9.1 and 10.1 speaker layouts. Note the "Voice of God" channel in the 10.1 Auro 3D system.

The sonic performance
The Auro-3D format creates a maximally immersive experience with the minimum amount of speakers based on 100% backwards compatibility of the existing 5.1/7.1 surround standard. Dolby Atmos’ speaker layout in cinema is not based on the 5.1/7.1 standard specs: the surround speakers are placed higher than the standard, are much more tightly spaced, and directed differently toward the center of the room. This has consequences, not only in the sonic performance (more clustering and phasing issues on the channel-based surrounds) but in the precision of the localization: objects moving from the screen to the side walls (very often ear-level objects like cars, bikes…) are positioned much too high and hence it feels like they start to fly. The vertical precision is completely off because all the sonic energy is over your head, creating an artificial feeling result. Is Atmos an advancement if it only improves the horizontal precision of the sound sources, while the vertical position is off in many cases? Do people realize that most moving objects in real life are around ear-level? The closer a sound is to its correct vertical position, the more natural the surround experience will be.

3D reflections are key in a natural sound
Of course there are more important factors besides the precise localization of sounds. More than 90% of what we hear in real life is 3-dimensional reflections around objects, and not the direct sound. The reproduction of those reflections should be done during the rendering in object-based systems as well, but it isn’t possible due to the DSP power required. That’s the reason why native recorded channel based sounds using the Auro-3D system do sound much more natural than mono or stereo objects in an object-based system: the latter are missing the crucial reflections in the full 3-dimensional hemisphere around the objects. Additionally, it’s not possible to reproduce those 3D reflections by using just a single horizontal plane of channels combined with ceiling speakers, like Dolby Atmos. The most important reflections do not come from above us but from the front and sides. For that reason, our unique “vertical stereo” field is a much better choice to recreate such 3D reflections around moving sources. 

Our unique “vertical stereo” field in front and all around the listener also allows superior reproduction of sound due to the delivery of more harmonic content (color/timbre), more depth, and more spatial information than competing formats. Objective neutral tests in scientific research centers have already proven that color/timbre is the most important parameter for human brains to achieve the most natural sonic experience. The precise localization of sounds is nowhere near the most important parameter like our competitors often highlight in their advertisements.

Vertical precision and spread of sound is key in immersive sound
In any case, object-based technology only has the effect of more precise localization when enough speakers are properly installed in a 3D hemisphere. Funny enough, using the Auro-3D 3 layered speaker layouts will create (without using object-based technology) more precision in the vertical axis than the 2-Layered Dolby Atmos system using 64 channels. Vertical precision is as important as horizontal precision, but vertical localization works for our brain in a different manner than horizontal. Our hearing system is horizontally-oriented and since we don’t have an ear on top of our head, we are not able to position sounds as phantom sources between two speakers placed vertically above each other. For that reason, more vertical layers of speakers are required with the lower layer being as close as possible to ear-level. This creates a more natural vertical spread of sound energy, which creates a more natural listening experience, feedback which we always get immediately when listeners compare both formats.

The Auro 11.1 and Auro 13.1 unique 3-layered speaker layouts

The most important sound is coming from the screen
Another important difference is the number of screen channels. Dolby Atmos is using the standard 3 main channels (L/C/R) and for large screens Lc and Rc as 5 channels in one single horizontal layer. In contrast, Auro-3D uses six screen channels in two vertical layers. Most engineers fall in love with Auro-3D initially because of the quality of the immersive experience thanks to the unique 3-layered system. However, after a few mixings they start to understand the power of having 6 screen channels, which gives them greater creativity, better A/V coherence, and more depth / transparency from the sound on screen. Even in an immersive format, this is still by far the most important part of the sonic presentation.

Auro-3D’s unique Height Layer
The next differentiator is that our Height Layer uses speakers in front of and beside the listener. Ceiling speakers are only needed for the” Voice of God channel” (directly above the listener), which is not a necessity in smaller home theaters. Installing height speakers thus far has never been a problem, in many hundreds of locations. At home, there is often room above the corner speakers of a standard 5.1 surround setup. Of course, if people don’t want to see cables on the wall, we have solutions for that, including wireless powered speakers.

Advantages of higher channel based scalability
Scalability is another positive factor. The Auro-3D format has channel-based configurations from Auro 8.0 up to Auro 13.1. This strategy has many advantages not only for content creation in all markets, but it also maximizes preservation of the creative intent, workflows, distribution, etc. Above a certain amount of discrete amplified channels (around 20), the use of object-based technology makes sense. But to avoid suffering from all the issues that full object based systems like Atmos must deal with, our approach stays different in order to keep all advantages related to the Auro-3D format as described above.

Future-proof speaker layouts
In commercial theaters, more is possible. For that reason I designed the Auro 22.1 format which uses the same speaker layout as the Auro 11.1 cinematic install, but deploys more zones naturally spread over the hemisphere. I always found it illogical to have the long side walls of a theater lined with an array of speakers creating a mono field, and then adding a stereo field on the back wall to create 7.1 surround. A better starting point would have been 6.1 with L/C/R along with side surrounds and a single back channel. From there, you can then make a stereo field at the sides and rear to create a 9.1 horizontal layer. The key to immersive sound is to mirror that same 9.1 layer, creating the Auro-3D Height Layer. The ceiling channels would be divided in the same way, creating a Top Front in stereo array as well a Top Back array in stereo. The end result is the Auro 22.1 speaker layout, which is an easy expansion by just adding a few amplifiers on top of the Auro 11.1 cinematic setup. The final option is the addition of the wide screen surrounds in lower and height layer, which creates the Auro 26.1 system.

Maximum preservation of creative intent
Fixed speaker configurations deliver better control for preserving the creative intent than the full object-based scalability seen in both competitors’ formats. Additionally, the Auro-3D Creative Tool Suite allows easy switching between pre-fixed settings, so engineers can check the compatibility while they are working on a mix. The goal is for all those deliverables to be created in the same time frame as used for a standard surround mix, which is possible using the Auro-3D workflow, which creates not only the standard 5.1 mix, but also the 3-layered Auro-3D formats and the object-based master that can be played back over a 2 layered full object-based Atmos system or the 3-layered Auro 22.1 / Auto 26.1 systems.

The Auro-3D format is the most accurate at matching the creator’s intentions, due to the consistent design of our speaker layouts in both commercial and consumer settings. A good example is for music production, where there is no need for object-based technology. The predictable channel-based workflow up to Auro 13.1 is a logical extension of how we have developed our 5.1 recording techniques. As content producers, this is one of the major uncertainties about the sonic results in an Atmos home install. As speaker configurations in Atmos or DTS are provided to the end-user with a wide range of ‘height’ options, the local rendering leaves us with an unpredictable result. I’d prefer the consumer come as close as possible to the studio quality and experience the 3D concept as intended by its creators. I don’t believe in open-ended options for speaker layouts, and this—along with studio quality—are key points for the Auro-3D format.

No extra hardware needed – DAW integration
On the studio side, the Auro-3D Creative Tool Suite uses the existing DAW stations, and don’t require a RMU renderer as Atmos does. This means that at every point in pre-production, engineers can work on their existing hardware systems. Another advantage is that we use internal automation in those programs. This allows the flexibility to switch easily between object-mode and channel-mode for each track or sound until the last minute because no automation is lost due to switching. This is not the case when using the competitors’ RMU renderer. This makes it much more flexible as well for the sound designers in preparing the pre-mixes as well the final mix.

Quality of Auro-Matic up-mixing
The Auro-3D Engine also includes Auro-Matic®, which allows legacy content that people have at home in mono, stereo, or 5.1/7.1 to be automatically up-mixed in the Auro-3D format. Developments since 2006 have made this algorithm into what we feel the most natural sounding up-mixer available. It is impressive how even mono up-mixed to Auro-3D sounds incredibly natural, without changing the artistic intent of the original mix. There is no addition of distracting reverbs or changing the tonal spectrum or dynamics like other up-mixing algorithms typically do.

Auro-matic up-mixes legacy content into the Auro-3D format.

Larger sweet spot.
The final big difference is the sweet spot. The larger the theater, the smaller the sweet spot will be with full object-based systems. This has to do with the SPL drop, since the distance from the speaker that is producing the ‘object’ can be far enough away in a theater that it is fully masked by the sound coming from the speakers around you. This is much less the case when an array of speakers is playing that source; it will be not perceived as being especially precise, but the audience does hear it in a balance which is closer to what was intended by the creators. The opposite is true with Auro-3D, where the sweet spot becomes even larger than with 5.1 and 7.1 surround sound because the concept is designed in such a way that the audience enjoys the experience as intended by its creators as much as possible. This is the advantage of using the Auro 22.1 or Auro 26.1 speaker layouts, which allow more zones while keeping the sweet-spot very big in large theaters. At the same time, the system doesn’t suffer from SPL drop through the use of speaker arrays. Of course, this will not allow large theaters to use spot-point sound reproduction by a single speaker in the surrounds. However, I wonder how important that capability is because such single-point sounds require much more of our attention to process. Human beings are about 2dB more sensitive for sounds coming from the non-visual field (versus sounds originating from the field of vision), and especially such direct sounds. As such, there’s a risk of full object based systems becoming too distracting from the action on screen. Because of this, I feel there is almost no use for static sounds reproduced as spot-points. Moving sounds coming from the screen typically have the speed and panning of sounds using a full object-based system, and the difference with our channel-based system is not noticeable.

They are many more differences in workflows, authoring, deliverables etc., but the above give already a brief summary of some major differences between the competing immersive formats. The more that people understand those differences, the more they understand the power and success of the Auro-3D format.

Auro 3D Interview Continued

Audioholics: What kind of commercial support is Auro-3D seeing and how do you think that will expand in the coming years?

Wilfried: The power of our technology is full backwards compatibility. Not only are our speaker layouts based on the existing surround standards, but our technology allows us to integrate the Auro-3D master in the existing PCM standard, mandatory in each audio device. This solves a huge chicken-and-egg issue, which is always the problem with a new standard. There is already content that people have at home: hidden away in many Blu-ray discs are Auro-3D masters within the standard PCM. This concept makes the integration simple, and that is attractive for content makers since no extra investment is needed for the distribution. The same goes for the consumer who buys only one product while having two formats without any audible concession in each format.

Auro-3D's Auriga A/V receiver.

Audioholics: When do you foresee Auro-3D making its way into consumer products?

Wilfried: When we decided to bring Auro-3D out of the cinema and into the home, we were determined to get it right. We wanted to deliver true “Immersive Sound” to the consumer, to be the first, but also to be the best. I’m incredibly proud that we at Auro Technologies have done exactly that. A/V receivers and sound processors are ready and available for consumers to order. There are 3 Auro-3D branded sound processors and many A/V manufacturers will be launching Auro-3D integrated processors by the end of this year as well. The first car that will have Auro-3D integrated will be available to purchase at the end of 2015. The tools for game developers to create games with Auro-3D’s immersive sound are available as of now. Within the foreseeable future, Auro-3D will also be available on mobile platforms, delivering high resolution “Immersive Sound” by using just a single file, making Auro-3D the ultimate end-to-end solution to all markets

Audioholics:  Is Auro-3D info encoded into a 5.1 PCM mix?  If so, how much does this increase size? (Atmos results in an increase of about 20% over True HD from what folks are saying).

Wilfried: Exactly. The Auro-3D cinematic mix uses an artist-controlled dynamic down-mix (so no matrixing) of all channels into a 5.1 PCM carrier using the Auro-3D encoder plugin, resulting in identical file sizes relative to a standard 5.1 PCM mix. This 5.1 PCM carrier sounds the exact same as if the same mix would have been done on a top digital console. Following our workflow, the Auro-3D mix and the 5.1 surround mix are both created at the same time without any compromises in the artistic intent of each format, and without any extra time needed than normally used for the 5.1 surround mix only. So this ‘single file’ master carrying both formats is going into the professional and consumer market as a 24 bit PCM stream (uncompressed audio) which can be put on each standard Blu-Ray or DCP (Digital Cinema Package). If a standard cinema server has our Auro-3D Decoder (just a software upgrade), it recognizes the metadata immediately and will automatically decode the signal into the original Auro-3D mix. The cinemas that don’t have the Auro-3D Decoder will hear the standard 5.1 PCM uncompressed audio.

The concept for home cinema is similar. All existing Blu-Ray players will play back the 5.1 Auro-encoded stream as a normal 5.1 surround mix, but A/V Receivers which have the Auro-3D Decoder and speaker layout will detect the Auro-3D mix. Due to our groundbreaking technology, we don’t need any change in specs or new delivery formats, nor extra bandwidth to bring an immersive audio experience with studio quality into the professional cinemas or to the consumers at home or on their mobile platforms.

Audioholics: Just to confirm, you’re saying that Auro-3D is fully compatible with Blu-ray?

Wilfried: Yes, Auro-3D is 100% compatible with the existing Blu-Ray standard. We use PCM uncompressed audio tracks (up to 8 tracks), and due to our groundbreaking Auro-Codec, we are able to add up to 16 additional tracks (24 in total) of high resolution audio. It does not even matter which HMDI version you’re running because the 8 PCM channels in Blu-Ray were already part of the spec from the beginning. This 100% backwards compatibility allowing us to carry multiple high resolution mixes is an important advantage of the Auro-3D format and allows easy integration in all markets.

Audioholics: How many channels of audio are possible with Auro-3D in the Cinema and the Home? The Auro-3D PDF mentions up through Auro 11.1, though it looks to be based on a 5.1 with 5 height channels and one top channel. We’re guessing it could go up to Auro 13.1 with a 7.1 base setup?

Wilfried: That’s correct. But it doesn’t stop with Auro 13.1 because above that number, we can use object-based technology to add more point sources on the 3-layered system. The question is how many people will install at least 20 speakers at home in order to have more precise localization of sounds for some flying objects? We don’t feel that a higher number of speakers automatically translates into a more immersive experience or improved sound reproduction. It is rather the opposite: each extra channel results in extra phase issues. The art is to create the most immersive experience with the minimum amount of channels related to the size of a room, and that is what we achieve with the Auro-3D format.

Auro's CEDIA demo included an impressive 20.1 setup.

Audioholics: Is the Auro-3D addition effectively lossy encoded discrete channels rolled into the PCM mix, or an object mix like Atmos?

Wilfried: Auro-3D technology preserves high-resolution audio for each channel, not only in the down-mixed master but also in each decoded channel. The concept is very simple. The dynamic resolution of 24-bit equals a dynamic range for more than 140dB, which means that on top of an extremely quiet background noise of 20 dB, you can achieve sound pressure levels (SPL) up to 160 dB… blood will come out of our ears. In fact, you can hear 24-bit only once in your life because if you have experienced it, you are just completely deaf. Additionally, there are no Digital to Analog convertors or amplifiers that can give this dynamic range.

So why do we use 24-bit? This is needed during the workflow for different technical reasons, but the moment we come to a delivery format, a dynamic range of 105 dB is more than enough, meaning peaks up to 125 dB SPL on reference listening position. Every bit equals 6dB of dynamic range. This means that an 18 bit lossless quality is the maximum we need as delivery format, confirmed by Tomlinson Holman (THX) at ICTS in 2012. The Auro-3D codec uses the 4 least significant bits (a noise floor you can’t hear) to put some metadata in, which allows us to reproduce each channel in high resolution quality.

In case of using object-based technology like Atmos, it is inevitable that much more bandwidth is needed if all objects have to be reproduced in a lossless audio quality. It’s unclear how Dolby could deliver 128 objects losslessly in a Dolby True HD stream on the existing Blu-Ray format!  The only way to have so many objects in the bandwidth available on Blu-Ray is to use a lossy compression scheme ... and therefore they could use AC4 which is the AC3 codec expanded with object based capabilities.

Even Dolby True HD is not 100% lossless... when sounds become very dense with many high frequencies, I know that MLP is not able to do that within that bandwidth. We already heard in our mastering room a difference between Dolby True HD decoded version and the original. This is not the case with DTS Master HD which is 100% lossless and creates the exact same bitstream as the original.

We all know that lossy audio codecs like MP3, AC3 or AC4 are causing distortion to the signal and are eliminating spatial information. Additionally, it has been proven that this subconsciously creates fatigue to the listener. I wonder how many people are going to install an immersive system with so many speakers to finally listen to a lossy audio quality? I prefer to go for the more relaxing experience of Hi Res Audio in each channel and no funny things due to too much freedom in speaker layouts. I believe that the scalability of speakers setup for home (Auro 8.0 up to Auro 13.1) is more than enough and will give the consumer an experience which is much closer to the original studio version as intended by its creators, being it movies, films or broadcasting of live events.

Audioholics: Looks like the speakers are located in the traditional “height” spots (excluding the 10.1 and 11.1 which use center height and top channels). Is this correct?

Wilfried: The Auro-3D speaker layouts are designed with a hierarchy in mind, meaning that we start with Auro 8.0 as the most efficient true 3D audio system. In order to achieve full backwards compatibility, we advise consumers at home to choose the Auro 9.1 system. Of course, for fly-overs and special effects, the addition of an overhead ceiling speaker (Auro 10.1) makes sense, but as already stated before, it is not necessary in smaller theaters. This third layer is treated as a mono channel in order to create the best scalability and largest sweet spot. In combination with the Height layer, this creates a very wide stereo field.

The height center speaker in the front (Auro 11.1 system) is needed in professional cinema theaters and is recommended for people who have a large screen at home. For very large home cinema theaters with at least 2 rows of seats, we suggest the Auro 13.1 system, which delivers the most immersive sound reproduction with the best audio quality and enough speakers to also make good use of object-based technology.

Auro-3D adds height channels over the existing 5.1/7.1 formats, and offers the option for "Voice of God" channels as well to complete their dome of sound.

Audioholics: Will Auro-3D allow for non-rigid speaker placements and be able to detect where the speakers are located in the room in order to adopt to the layout?

Wilfried:  Our speaker layout already has a tolerance which we believe is big enough to install an Auro-3D system within our specs everywhere. More than 350 systems are already installed within the specs without the need for reconstruction. The deviation beyond our tolerances will always lead to less compatibility with the creative intent, even when using object-based technology. It all sounds great that technology is able to recalculate poor placements of speakers, but consumers should be very careful with these kinds of marketing claims. The tolerances to do that kind of mapping properly are much smaller than people would believe, even with the use of object-based technology.

Audioholics:  Will Auro-3D offer an option like Atmos Elevation speakers to bounce sound off the ceiling or do you find that method to not be an effective solution?

Wilfried: First of all, to create the most immersive sound, you don’t need sound from the ceilings but a vertical stereo field in front, sides and behind the listener between ear-level and a height of about 30°. The sound bouncing off the ceiling can never create the same quality of sound reproduction. Of course we looked into that as well, but we don’t like to make false promises. This doesn’t mean the effect won’t work, but it is not comparable with the real thing.

Elevated sounds cannot be created as vertical phantom sources without the use of psycho-acoustic effects like those used in the horizontal plane by using ‘sound bars.’ The quality of sound bars in the horizontal plane is not comparable with a 5.1 or 7.1 speaker system, and it will be even worse using that technology for the reproduction of height.  The use of such psychoacoustic effects (like notch filters) will always have a bad influence on the original sound quality of those height channels. The modes of the low to mid frequencies down to less than 300 Hz are key for our brain in spatial sound processing. The material of the ceiling has to reflect all those frequencies in the same way, as if the sound were coming from a height speaker. That is impossible. For that reason, above the ear-level layer we use a Height layer with speakers around the listener to enable the reproduction of the elevated source sounds as well as the most important native true 3D reflections around those source sounds.

Auro-3D supports various speaker layouts for the home, ranging from their Auro 9.1 setup for most home installations, up to Auro 13.1 for larger home cinemas. Auro 9.1 is based on a standard 5.1 Surround setup for the lower layer, augmented with four height speakers, sometimes referred to as the quadrophonic sky, positioned at 30º above the front left and right speakers. This setup is considered to be the minimum setup for real “Immersive Sound”, with a level of realism that can barely be surpassed by any other system given that the majority of the immersive effect is created by the interplay of the lower and height layers. From Auro 10.1 onwards, the speaker setups also have the third layer on the ceiling, to complete the ‘dome of sound’ all around the listener. This top channel is then mostly used for special effects such as fly-overs, similar to what happens in reality. The well-defined and fully compatible speaker layouts of the Auro-3D format for cinema and home guarantees the same immersive sound experience as it was originally intended by its creators.

Auro will NOT support Dolby's Atmos-enabled speakers, such as Pioneer's new Elite loudspeaker lineup.

Audioholics: Is there one unified speaker layout that would be compatible with Auro, Atmos and DTS UHD?  If so, how many speakers would that involve and in what layout scheme?

Wilfried: In order to maintain cross-platform compatibility, we would suggest the Auro 9.1 which is 5.1 bottom + four Height speakers located 30° above the ear-level front speakers. This is close to the 5.1.4 format from Dolby, with the difference being that the angle to the listening position of the ceiling speakers will be closer to around 50° to 60°. This is a significant difference, and Auro-3D native productions could sound funny because reflections and source sounds mixed on 30° elevation for the Height channels won’t sound quite right being reproduced at around 50 to 60°. But if people install the Auro-3D speaker layout, they can playback Auro-3D content properly and due to Dolby's and DTS's claim that their object-based technology allows them a wide range of speaker layouts, an Auro 9.1 layout should provide good results there as well.

The Auro 9.1 layout seen above should allow cross compatibility with the Atmos 5.1.4 layout.

Audioholics: What are the interactive possibilities with object-based technology for consumers?

Wilfried: The most important interactive possibilities can be integrated in the metadata of the Auro-3D encoded stream. We don’t need to go for object-based technology to cover most of those options. Too much freedom is not a good thing. I remember when they offered multiple video streams for movies so people could select different camera positions in Europe. Everybody thought it would make a big difference but it failed completely because after people tried it out a few times, they just switched back to the main program again. We should not overblow the need of such options and make the consumer invest in things they don’t really need. Being immersed by a high quality, true 3D system at home will make people happy, while allowing them to enjoy all of their favorite music and film content in a new way. Bringing that final dimension in the evolution of sound to the world seemed to be my mission. Seeing this happening now makes me very happy.

Audioholics: What Auro 3D titles are currently available on Blu-ray?

Wilfried: The list of titles currently available are:

• Trondheim Solistene - Souvenir (http://www.2l.no/pages/album/090.html)
• Remote Galaxy by Flint Juventino Beppe (http://www.2l.no/pages/album/100.html)
• Mando Diao - Aelita (http://www.mandodiao.com/official-media)
•  Lichtmond 3 (to be released Oct 10th - http://lichtmond.com/index_en.php)
• Crossover Experience Volume 1 (http://www.sa-cd.net/showtitle/9816)
  

and we are currently working on many more to come (soon to be announced)

Audioholics: Will Auro-3D support streaming services via DVR’s and STB’s?

Wilfried: We are working on the streaming side of things and we are sure this will be available in the future. As of now, Blu-Rays are the way to go for now (either via decoding or upmixing with the Auro-Matic).

That's a Wrap!

We would like to thank Wilfried for the time he took to give us an inside look at the Auro-3D format. We were able to demo an Auro-3D system built around a Datasat processor and James Loudspeakers at CEDIA 2014. To say we were impressed would be an understatement. It was in fact the best sounding multi-channel surround demo we heard at the show (though to be fair, we didn't catch the JBL demo which received high marks from others).  The sense of scale and ambiance added by the height information is nothing short of breathtaking. We can't wait for more Auro-3D products to start hitting the market so we can test them in our own listening environment.

For more information, visit the Auro-3D Official Website