Immersive audio – finding the sweetspot12 November 2014
After looking at the main players in immersive sound and the various applications of the technology, Installation concludes this series by looking at the approaches being taken by companies to ensure everyone gets the same immersive experience. David Davies reports.
As the different technologies vary in their approach, so too does their philosophy with regard to the ‘sweetspot’ and the extent to which those present in the room have broadly the same experience, no matter where they are situated.
In the case of TiMax SoundHub, the delay-imaging capability provides the primary benefit of “the broadening or actual elimination of any sweetspot. At the pre-show at the NASA Atlanta Space Shuttle exhibit at Kennedy Space Center, a 7.1 music/FX/dialogue mix is mapped by TiMax onto about 21 speakers where it provides, even to the post-production mixer’s ears, a more faithful but intimate soundcape over most of the audience area, with much less awareness of the physical loudspeakers themselves.” In the case of museum, art installation and other exhibit spaces, TiMax is often used to create “continuously variable soundscapes for both static and mobile audiences. These can be automated by internal show control schedulers, or externally controlled by things like MIDI, Timecode or IP,” says Out Board director Dave Haydon.
On the other hand, Auro-3D is said to yield an “even larger” sweetspot than 5.1 or 7.1 surround formats thanks to the use of zoning. “The aim of cinema exhibitors has always been to give the same audio experience as intended by its creators to each seat,” notes Auro Technologies’ CEO, Wilfried Van Baelen. “This is much more difficult with full object-based systems since they create a much smaller sweetspot due to different technical reasons, the SPL drop (when sitting further from the speaker), and the directivity of all the surround and ceiling speakers in order to give a consistent spectrum of the object-based moving sounds. For that reason, the Auro-3D format is using ‘zones’ (more speakers together creating a zone), which very much enlarges the sweetspot, even when using object-based technology.”
With Iosono, Barco senior director strategic business development entertainment Brian Claypool emphasises the technology’s ability to satisfy the requirements of each given application: “Whether the experience presents itself as being similar for all listeners with only little impact of the listening position, or with considerable changes that come with change of the listening position, depends on the intended use of the venue and content [as well as] on sound and system design.” Accordingly, “venues that are expected to give broadly the same experience to all listeners, such as cinemas and planetariums, are optimised to do exactly that. Systems for moving audiences such as themed entertainment are designed to follow that idea.”
Not surprisingly, most vendors stress the extent of the support they are able to offer to end-users and integrators seeking to deploy these new-generation systems. Some issues, though, are timeless. “The difficult part is always hiding cables,” notes Van Baelen, although he says this is “not difficult in a dedicated home cinema theatre where mostly all speakers and cables are hidden behind the acoustical fabrics. But we are working on ‘wireless powered’ speakers, which means that no cable is needed to provide the speaker from power.”
The greater availability (and, more to the point, affordability) of wireless audio will surely be a vital factor in determining how widespread immersive sound environments ultimately become. But with the Barco/Iosono announcement indicating the beginning of convergence and consolidation in the marketplace, expect the commercial push for commercial and residential applications to become increasingly acute.