Driven by the explosive growth of the DVD format and falling prices for home theater systems, multichannel surround sound has proven its ability to create a more life-like and enjoyable entertainment experience for the consumer.
Building off the momentum and success of the home theater market, surround sound technology is now migrating to a variety of other applications including gaming, PC multimedia and streaming, portables and headphones.
Inspired by the success of surround sound in the home theater markets, console manufacturers are turning to multichannel audio to create a more realistic gaming experience.
Multichannel audio offers game developers greater control over audio tracks and effects – allowing them to surgically steer sound sources, create accurate acoustic images and envelope gamers in expansive audio environments that match the stunning graphics of the latest gaming titles.
For instance, Microsoft’s XBOX includes hardware support for Dolby Digital 5.1 surround sound (must be used with an add-on cable with optical out) that allows you to savor the creative use of surround sound in both cutscenes and game play. Halo, developed by Bungie Software and published by Microsoft, exemplifies the ability of multichannel audio immersing gamers in the action.
All systems that support game play did not immediately adopted this technology. For example, Sony’s Playstation 2 did not support multichannel surround sound when it first shipped. Sony and DTS technologies have since developed a way to install a small software encoder that is stored on the game disk and can be loaded into the system during gameplay. SSX Tricky is often sited as one title that makes the most of this console’s audio capabilities.
Nintendo’s GameCube currently does not support either Dolby Digital or DTS 5.1. However, it does provide matrix surround technology through Dolby ProLogic II.
PC manufacturers are also striving to meet and exceed features available on the latest consoles. Instead of relying on the processing power of the latest host CPU, they are busy working with the sound card and other hardware vendors to enable pervasive 3D positional audio gaming environments.
PC Multimedia & Streaming
With its recently unveiled Windows Media 9 Series, Microsoft is helping push surround sound beyond gaming and PC-based DVD playback.
While WM9S incorporates a much larger set of technologies and software applications, surround sound enthusiasts will be most interested in the 7.1 capabilities of the Windows Media Audio 9 Professional (WMA9-Pro) audio codec – the first Internet-based codec that will deliver surround sound capability.
One example of an application of the technology is the recent work Microsoft has done with Peter Gabriel to debut his latest album “UP”. Debuting in a 5.1 multichannel format, the multichannel mix marks an important milestone. Although this does not exercise the full 7.1 capabilities of the WMA9-Pro format, Gabriel’s album is the first commercially available multichannel digital download available on the Web.
In addition, with WM9S plug-ins, PC users can take advantage of multichannel plug-ins available from third parties. SRS Labs leads the plug-ins efforts with two surround sound products: SRS CS-II and TruSurround XT. The first decoder plug-in will allow consumers to listen to 5.1 audio from mono, stereo and surround encoded material using the Circle Surround II decoder. The TruSurround XT virtualization plug-in is already featured in a variety of consumer electronics and allows users to enjoy positional audio over standard stereo speakers.
Portables & Headphones
Multichannel audio is also making a strong push in portable entertainment markets with the increasing popularity of portable DVD players and the emergence of multichannel music (enabled by new formats like SACD, DVD-Audio and WMA9-Pro).
Since consumers typically do not carry a full multi-speaker setup, the markets demand headphones that allow them to take full advantage of the multichannel audio content similar to that of their home theater.
Several companies including Dolby, SRS, Spatializer and QSound, are addressing this need with headphone virtualizers that mimic the immersive sound stage of a true multi-speaker home theater setup.
But, recreating an immersive sound stage, a well-defined center image and clear dialog using traditional headphones presents a number of challenges. In a real home theater setup, the sound signal generated from each speaker reaches the listener’s ear not only directly but also from reflections off the objects and surfaces in the room. These reflections create a unique “sonic signature” that provides the listener with the acoustic properties of the listening area.
When a consumer uses headphones, the speakers are immediately next to their ears and the signal lacks the sonic signature that would provide positional and ambient details. Furthermore, since the sources are immediately to the left and right of the listener, they create an “inside-the-head” image between the ears.
One way to correct this problem is through headphone virtualization. This involves superimposing an artificial sonic signature onto the original speaker to recreate the ambience and positional information of a real home theater setup.
Another limitation of headphones is the poor frequency response in lower frequencies that results in weak bass. Many virtualizers address this by improving the bass performance of headphones. For example, Spatializer’s Natural Headphone? also includes the Spatializer Virtual LFE? “virtual subwoofer” that improves the bass extension of frequency response-limited headphones.
The rapid adoption of the DVD format and growth in home theater sales has brought surround sound to the consumers. With its ability to create a dramatically more realistic and immersive audio experience, multichannel audio is now migrating to applications and systems beyond its original home in the home theater. The proliferation of multichannel audio will continue to accelerate as the availability of content in multichannel formats increases and audio DSP technology becomes more powerful and less expensive.
Mohsin Imtiaz serves as the Marketing Manager of Texas Instruments’ Performance Audio group. He works with worldwide sales to win new business, driving product rtm (release to market) and ensures TI’s roadmap reflects market needs and positions the company to succeed moving forward.
During his career at TI, Imtiaz has also served as the product marketing manager for cable broadband communications. He has also served as the DSP Product TSR.
Imtiaz holds a bachelor of science in electrical engineering from the Georgia Institute of Technology. He and his wife Farhina have two children. His hobbies include racquetball, running, music and reading.