Originally posted by: The J
1. THX Certification for PC speakers really doesn't mean too much. It just means that the company paid THX for testing and passed (you basically need something like a 125Hz LFE crossover and easy setup to pass, I think). For example, the Klipsch ProMedia Ultra 5.1 are considered to be tops when it comes to PC speakers and they are NOT certified.
2. EAX is just an algorithm to simulate different environments. Whether or not it sounds better depends on the application that uses it and doesn't matter with speakers. Creaitve Labs has EAX 5.0 with the X-Fi and EAX 4.0 with the Audigy cards. Non-Creative cards have EAX 2.0.
Dolby Digital and DTS are just digital compression techniques used for DVDs. The Audigy cards can decode Dolby Digital EX and the Audigy 2 ZS and above can decode DTS as well (the X-Fi can decode DTS:Neo6). Many DVD players, like PowerDVD, WinDVD, and the nVidia Decoder, can decode DTS and DD in software. Media Player Classic, which is free, can also decode those. The Audigy cards have a hardware decoder, I think.