surround
1. Dolby Digital
2. DTS
3. SRS
4. Sound Blaster X-fi surround
5. THX TruStudio Pro Surround
6. Sound Core3D
7. Audyssey DSX
13. philips fullsound and surround
14. NVIDIA SURROUND TECHNOLOGY
17. EAX 5.0 (Environmental Audio Extensions)
18. A3D (Aureal 3-Dimensional, now defunct)
19. Sensaura by Creative