The market offers various options for encoding and decoding multichannel audio streams for surround-sound applications. Some options are derived from older technologies, while others are limited by hardware support for specific equipment. ASTi has developed a system that delivers a cutting-edge, immersive listening experience and supports a wide range of hardware and speaker setups. ASTi's Earshot differs significantly from a traditional 5.1-channel surround system. A Dolby 5.1 system only supports six speaker channels (i.e., left, center, right, left rear, right rear, subwoofer), whereas Earshot supports an almost unlimited number of channels.
Dolby 5.1 systems require specific, fixed speaker locations to perform well, with each speaker offset by a certain number of degrees from the straight-ahead position. In contrast, Earshot can accommodate any speaker arrangement and allows for user-definable speaker locations. Unlike Dolby 5.1, Earshot supports audio in all three dimensions (i.e., left/right, front/rear, up/down).
Most importantly, Earshot uses position data to encode each sound into the sound field, which Voisus then decodes to "best fit" the loudspeaker positions. If you change the number and positions of the loudspeakers in an Earshot system, the sound generation and encoding part of the system remains unchanged. The system automatically rebalances the sound field for decoding once you configure the speaker positions. This is quite different from the fixed position definitions used for a 5.1 system. For instance, if you need to change the left/right speakers from a 30-degree offset to a 45-degree offset, you must adjust the entire mix. In contrast, Earshot offers significant flexibility; for example, you can easily redeploy a system designed for a large 30-foot dome with 16 loudspeakers to a small 12-foot dome with eight loudspeakers.