Audyssey DSX

Matching human perception

Realistic reproduction of sound relies on the ability of audio systems to match human hearing performance. The three key requirements are: (1) frequency response, (2) dynamic range and (3) accurate spatial rendering. With 96 kHz sampling rate and 24 bit word length, the requirements for frequency response and dynamic range have already been surpassed by today’s digital audio systems.

Limitations of 5.1 Surround Sound

5.1 surround sound was a significant improvement over 2 channel stereo. Imaging was improved by adding a center to the left and right front channels to anchor the center of the soundstage. Envelopment was improved by adding two surround channels that envelop the listeners with ambient sound.

More channels are needed

Research in human hearing shows that we can hear many more directions than what current systems provide. We use the direct sound to localize the direction of sources and the reflected sound to perceive the size of the soundstage.

Experiments have shown that human localization is better in front than to the sides or behind. This means that for front-weighted content such as movies and most music, good engineering dictates that we employ more channels in the front hemisphere than the back. Imaging is also better horizontally than vertically and so good engineering also dictates that channels must first be added in the same plane as our ears before going to higher elevations.