MOL, BELGIUM—When 5.1 first became available in the home, at least one consumer electronics manufacturer marketed the multichannel surround format as “immersive sound.” More than two decades later, immersive sound has become the generic term for those formats that include overhead channels, thanks in no small part to Wilfried Van Baelen, CEO of Belgium-based Auro Technologies.
Van Baelen, who founded Galaxy Studios with his brother Guy in 1980, had been experimenting with multichannel formats for some time when he mixed a project in 2005 for a German artist, Sylvia Diaz, in 5.1 plus two height channels. When he introduced his Auro 9.1 and 11.1 formats at AES events in Paris and San Francisco in 2006, adding a height layer to 5.1 and 7.1 layouts, he was still looking for a marketable descriptor. “In 2010, when I launched the Auro-3D format in Tokyo, I proposed to call this three-dimensional format immersive sound, and it has become the generic term for sound in 3-D,” he says.
Consumers and professionals alike, perhaps struggling with the conceptual differences between channel-based and object-based audio formats, have sometimes conflated immersive sound with object-based delivery formats. “It’s probably one of the most confusing things happening in the industry,” says Van Baelen. “It’s important to make clear there are three [immersive sound] formats on the market—Dolby Atmos, DTS:X and Auro-3D—and they are all hybrid formats, part channel-based and part object-based.”
More than 600 cinemas have committed to or installed Auro 11.1 by Barco, and well over 50 major mix stages worldwide, including Skywalker Sound, Sony Pictures and Warner Bros., have integrated Auro technologies. In 2015, projector manufacturer Barco, Auro’s exclusive partner for Digital Cinema, introduced Auro-Max, a system that incorporates support for the placement of objects in any immersive mix.
Auro-3D, a scalable system compatible with small and large room speaker layouts from 9.1 through 13.1, differs from its two competitors, says Van Baelen. “Auro-3D is the only immersive sound format on the market that can record, mix and reproduce a 3-D space in channel-based technology only.”
Being channel-based offers some advantages, he believes, most significantly in the quality of the audio. For example, objects are frequently mono sources, which, with associated metadata, are rendered during playback. “But those sounds don’t contain the 3-D reflections,” he says.
“Our hearing system is very trained and sensitive about these 3-D reflections, because they help our brain to localize sounds, to understand the size, how it moves, where it is. The most important part, in a natural sound, is still the timbre—the color. That color is related to how 3-D reflections are recorded and reproduced. And those reflections cannot be reproduced by the renderers at playback from object-based formats.”
Van Baelen claims that he discovered during his experiments with vertical panning that exceeding a certain angle between the lower and upper speaker layers results in a loss of coherence: “I found that when that vertical angle of the speakers is greater than 40 degrees our brain hears two different sources. It’s not the same as the horizontal field…so there is a relationship between our speaker layout and the fact that we have the most natural sound. It’s the speaker layout and our technology.”
Adding to that natural sound, he also argues, is that Auro-3D supports high-resolution audio. “In the movie industry, 48 kHz is the standard, although there is an option for 96 kHz that is typically not used. But in the music industry, 96 kHz has been the production standard for a few years.”
The ability of Auro-3D to deliver hi-res music on Blu-ray is driving the release of an ever-growing catalog of music recorded and/or mixed in the format by companies such as Sony Entertainment; 2L, owned by Morten Lindberg, who has over two-dozen Grammy nominations, including for surround projects; and multiple Grammy nominee David Miles Huber (featured in PSN, Aug. 2017), whose music is released on the Auro-3D Creative label.
Being a channel-based workflow again offers an advantage, says Van Baelen. “You cannot record in an object-based format; it’s a rendering format. And because we are channel-based, we can do the mastering first and then the encoding, and then you have an Auro-3D mastered product. Our format translates the artistic intent much easier compared to other formats.”
As for delivery, he says, Auro-3D 11.1 and 13.1 need no extra bandwidth beyond that of a 5.1 or 7.1 PCM carrier, unlike competing products, which require extra bandwidth for the height channels. And there is no requirement for ceiling speakers; Auro-3D’s height channels are instead positioned at the top of the side walls, enabling an easier installation in the studio or at home, he claims.
Van Baelen, who enjoys listening to spiritual music, recorded some gongs at high-resolution. “If you play it back over stereo, the magic is lost. In Auro 9.1, you get a connection to your body. This is about the experience. The emotional connection is so much higher, and more relaxing to your brain.”