Different Types of Dolby Audio Speakers Formats

Showing the different Speakers setups.

Dolby Stereo uses 2 separate channels for audio… left and right. 

Dolby Pro Logic uses 4 separate channels for audio… left, center,

right, and one channel for rear surround.

Dolby Digital uses 5.1 separate channels for audio… left, center,
right, left rear, right rear, and an LFE (low frequency effect or
Subwoofer). 

Dolby Digital EX 6.1 uses 6.1 separate channels for audio… left,
center, right, left rear, right rear, center rear, and an LFE (low
frequency effect or Subwoofer).

Dolby Digital EX 7.1 uses 7.1 separate channels for audio… left,

center, right, left side, right side, left rear, right rear, and an LFE (low

frequency effect or Subwoofer). 

Dolby TrueHD can use up to 8 channels of audio and was developed

for high-definition disc-based media.