Whatever streaming new media you use in your home, you can’t escape from needing CD DVD players. In spite of the advent of digital media stored on hard drives rather than disks, and played back through MP3 players and other media players, the vast majority of movies are still stored on discs. DVDs offer much higher quality video than any download formats currently available, and CD audio holds much bigger files than the MP3 format, making for better sound.
CD and DVD players have to create the illusion of realistic sound in both music and movies. In order to create the illusion of realistic sound, audio engineers have devised a dizzying array of home theater and audio formats. These days, most mp3 and media players, in tandem with surround processors, will play most and sometimes all of these file types. Here, then is a brief field guide to home theater audio formats.
Most CD and DVD players have support for most, even all, of the various surround sound formats available on DVDs today. Surround processors specify their capability by number of channels they allow. For example, 5.1 sound consists of one center channel, a left and right channel, and two surround speakers and a subwoofer (the .1 part). Incidentally, you need at least two loudspeakers to create the illusion of sound having any direction other than from the speaker itself. These days, there is a trend toward adding more and more speakers. You may see systems and surround processors offering 7.1 or 8.1. All this means is that they have more surround speakers.
Your CD DVD players must be able to handle many audio formats. Dolby Surround was introduced by Dolby labs it is an acoustic algorithm that added an extra speaker behind the audience. Unlike more current technology, it’s not a separate channel but is derived from a stereo signal. Dolby Pro-Logic was an incremental improvement on Surround. That added a center channel for film dialogue. Dialogue in films is always in the center of the screen regardless of where the actors are placed because otherwise the audio cuts would be too jarring for viewers, as our hearing is wired very different from our visual cortex. Pro Logic was still a matrix developed for a stereo signal. Dolby Digital 5.1 was the first format to have separate (discrete) channels beyond the two stereo channels.
Your CD and DVD players should also be able to decode DVDs encoded in DTS formats. DTS is a company that formed as an alternative to Dolby Labs. DTS soundtracks can now be found on many popular DVDs and are included as an option for many popular MP3 and media players. DTS have a higher sampling rate than Dolby Digital, which results in a palpably better audio quality when all things are equal, and slightly more emphasis on sound effects. DTS is the favorite home theater format of audiophiles.
