Understand Surround Sound Systems
Surround Sound is the concept of expanding spatial imaging of sound playing from 1 dimension (mono / left right) to two or three dimensions. It is often used for a more realistic sound environment that is actively implemented in theater sound systems, technical theater, home entertainment, video arcades, computer games and a growing number of other applications. Many popular surround sound formats have evolved over the years. These include ambisonics, quadraphonic, Dolby 5.1 Surround sound, DTS and MP3 Surround.
Surround sound can be created using various methods. The easiest to understand, several speakers use the listener to play audio from different directions. Another approach involves processing the sound using psycho-acoustic audio localization methods to simulate a 3D sound field using headphones. The third approach, golf field synthesis, uses a very large number of speakers to generate the sound hologram of the original sound in the whole room (since 2004 is the only commercial implementation of this Iosono). Surrounding sound is not limited to placing speakers next to a flat (two-dimensional) plane. Vertically located sound sources can be considered.
Dolby Digital (DD) uses the AC-3 file format, which can decode any Dolby Digital Decoder to produce 5.1 audio. Dolby Digital is the technical name for Dolby’s multi-channel digital audio coding technique, more commonly called Dolby 5.1. A channel-coding process originally created by Dolby for theaters, AC-3 is later adapted for home use and is becoming the most common audio format for DVD.
Six discrete audio channels:
3 front left-hand speakers – left (L), middle (C) and right (R)
2 for surround or rear surround (SL) and surround right (SR) surround speakers
1 low frequency Effective (LFE) channel carries basic audio effects supported from 10 Hz to 120 Hz, which can be used by a subwoofer. (This is the ‘.1’ in ‘5.1’.)
DTS is a code / decoding process that delivers 5.1 channels of “master quality” audio to CD, CD-R and DVD. Each DTS encoded disk represents a sonic “clone” of the original movie soundtrack.
The difference between Dolby Digital (AC-3) and DTS is:
DTS offers a deeper and stricter low-frequency presence.
DTS sounds breathless. Transparency
AC-3 gives the impression that something is missing from the mix.
At lower bitrate AC -3 starts to sound like MP3s encoded at low quality 96kbps
DTS is more three-dimensional. The sound actually moved from the individual speakers to sound more full. This fullness was most apparent with the music. Instead of just coming from the speakers, the DTS filled the front soundtrack not only from side to side, but also with depth. Bass propagation is also more defined in the DTS version, which leaves the DD edition that looks muddy.
Dolby Digital contains dialog normalization, which changes the decoded level of the soundtrack. The typical setting reduces the level by 4 dB; Other reduction levels are possible. In most decoders, this leads to a decrease in signal and dynamic range.
Dolby Digital also offers a stereo down mixing feature as a substitute for a dedicated stereo mix. However, many production engineers acknowledge that they often need to edit the original 5.1 blends to achieve acceptable stereo blends. Therefore, the 5.1 mix on many Dolby Digital DVDs may differ from the original master.
5.1 Surround Sound Headphones:
While the traditional surround sound method as described above, many speakers use to produce the entire sound field, the surround sound mix is limited to a two-channel stereo mix when using headphones. Therefore, the latest developments in surround sound technology include 5.1 surround sound headphones, so you can get the same sound quality and surround sound experience without making neighbors or disturbing roommates.