SRS (Sound Retrieval System) is proprietary technology from SRS Labs, which Apple has licensed and implemented on the Power Macintosh 5400 and 6400; Macintosh Performa 6400 series; and Macintosh Performa 6360/160 computers in order to enhance the sound field of these computers.
The useability, compatibility, and performance of the computer is not affected if SRS sound is enabled or disabled. However, enabling SRS yields a more spacious stereo sound from the computer. You can try it both ways to determine which you prefer.
Stereo, Surround Sound, and SRS are all common forms of sound expansion techniques, but SRS differs primarily because it does not require special encoding or recording processes or critical listening position ("sweet spot").
Instead, SRS uses psychoacoustic (how your ears and brain interpret the sound) principles. The result is that any sound can be played back using SRS and you do not need to listen to it from a specific location to experience the effect. SRS accomplishes this by processing the ambient or reflected sounds so that they take on the audio characteristics of sounds naturally entering the ear from the side. The brain thus perceives these sounds as though they were actually coming from the sides or, in some cases, from behind the head, rather than from the two front stereo speakers.
The following chart provides an overview of the differences among stereo, surround sound, and SRS. Additional information about SRS is available from SRS Labs web site
http://www.srslabs.com/
+------------------+----------------+----------------+----------------+
| | | | |
| Characteristics | Stereo | Surround | SRS |
| | | Sound | |
+==================+================+================+================+
| | YES | YES | NO |
| Encoding |Using 2 or more | Using 4 or 5 |Works with any |
| | microphones | microphones |source such as |
| | | or special |mono, stereo, |
| | | techniques |or surround |
| | | |technologies | +------------------+----------------+----------------+----------------+
| | YES | YES | NO |
| Channels |Left (L) & |4 or 5 channels | |
| |Right (R) |Front left chan-| |
| |channels. |nel to front rt.| |
| | |speaker, and so | |
| | |on. | |
+------------------+----------------+----------------+----------------+
| | | 4 or 5 | |
| Speakers | 2 | Surrounding | 2 |
| | | listener | |
+------------------+----------------+----------------+----------------+
| Sweet spot? | YES | YES | NO |
+------------------+----------------+----------------+----------------+
Note: The word 'SRS' and the SRS Symbol - (*) - are registered trademarks of SRS Labs, Inc.