Major movie houses, theatres, home entertainment environments, gaming, arcade and other public and in-house presentation areas today use surround sound systems for enhanced audio entertainment. Surround sound is basically when you increase the dimension of your sound (or sound waves), sort of like on the Twilight Zone. In other words you take the standard one dimensional audio production, referred to as mono / Left-Right, and turn it into multiple dimensions; two or three.
Sound Systems
To create surround sound, you can go any one of several different directions. The simplest and probably the oldest way, would be to set up a bunch of speakers surrounding the audience, so that the sound comes in to the listeners from all over, from the different directions.
A different method is to combine the use of headphones with localized audio production with psychoacoustics. The result is a simulated three-dimensional effect.
And another way to create surround sound is with ambisonics where you reconstruct the sound at a central point. However, you get a gradual decline in quality as you move outward.
Still another way is to use wave field synthesis (WFS), with multiple loudspeakers and a computer aid.
Popular today are everyday devices like stereo, PC soundcards, some camcorders and AV receivers. These feature digital signal or audio processors that create surround sound via stereo sources, or have add-ons, as in some camcorder cases.
Formats
Just as nothing stays the same, ditto with sound formats. Top ones have included
discrete 5.1 Surround sound format with DVD-Audio, also known as DVD-A and SACD which stands for Super Audio CD. Moving on you have ambisonics, quadraphonic then Dolby 5.1 Surround sound. And later are: DTS, DVD-Video or DVD-V and the latest MP3 Surround.
Surround Sound Specs
3.0 Surround (matrixed):
3 audio channels: 2 for speakers front – left, right; 1 rear
4.0 Surround (matrixed Quadraphonic):
4 audio channels: 2 for speakers front – left, right; 2 rear
4.1 Surround (matrixed Prologic):
4 audio channels: 3 for speakers front – left, center, right; 1 rear (.1 = subwoofer)
5.1 Surround (matrixed Prologic II):
5 audio channels: 3 for speakers front – left, center, right; 2 at rear or side (.1 = subwoofer)
5.1 Surround (discrete Dolby Digital, DTS):
5 digital audio channels: 3 for speakers front – left, center, right; 2 at rear or side (.1 = subwoofer)
6.1 Surround (discrete Dolby Digital EX, DTS-ES):
6 digital audio channels: 3 for speakers front – left, center, right; 3 for the rear / side (.1 = subwoofer)
7.1 Surround (discrete SDDS):
7 digital audio channels: left, right, center, left surround, right surround, left rear, right rear positions (.1 = subwoofer)