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Details of 5.1-channel Surround Sound

A system with five speakers and one subwoofer, each reproducing a separate audio signal. By contrast, a system that simply reproduces the same audio signal from five speakers is still monophonic.
The speakers are positioned at the front left, front right, front center, left surround, and right surround. The subwoofer that produces the bass sound can be positioned wherever desired but is usually placed somewhere in front because bass sound is not highly directional.

Details...

5.1 Channel Surround (analog matrixed: Dolby Pro Logic II)

Extracts 5 audio channels from either a specially encoded two-channel or a stereo source:

• Two channels for speakers at the front - left (L) and right (R).
• One channel for speaker at the center - center (C).
• Two channels for surround speakers at the rear - surround left (LS) and surround right (RS).
• One low-frequency effects channel (LFE).
• Describes the Dolby Pro Logic II matrixed surround system. Source media is often branded with "Pro Logic II" logo. Most modern theatrical motion picture films include a digital soundtrack in this format.
• Surround sound speaker placement: (6 speaker channels in total) surround sound speaker placement is different for both music and movie content.

For music, speakers should be placed closest to the left and right of the listening position, close to that of the 6.1 surround speakers.

For movie surround, the front speakers should be placed at the edges of the screen, toed in to face the central listening location, and the tweeters should be ear height. The center speaker should be placed behind the screen (when using projection) or over or under a TV, and as close to ear height as possible. Rear channel speakers should be placed high on side walls, slightly behind the listening position, and should have a normal high-quality monopolar construction.

5.1 Channel Surround (digital discrete: Dolby Digital, DTS, SDDS)

Delivers 5 discrete audio channels and 1 LFE channel from a 6 channel source:

• Two channels for speakers at the front - left (L) and right (R).
• One channel for speaker at the center - center (C).
• Two channels for surround speakers at the rear - surround left (LS) and surround right (RS).
• One low-frequency effects channel (LFE).
• Describes the Dolby Digital, Digital Theater System (DTS), and Sony Dynamic Digital Sound (SDDS) systems. Source media, usually DVD and sometimes Laser Disc or satellite/digital cable is often branded with "Dolby Digital" and/or DTS logos.
• DTS uses a higher sampling rate than Dolby Digital, thus DTS uses less compression and achieves higher fidelity than Dolby Digital.
• Surround Sound speaker placement: (6 speaker channels in total) Surround Sound speaker placement is different for both music and movie content.

For music, speakers are placed in a circle around the listener. The center channel has 0º offset, left and right are offset ± 30º, and the left/right surrounds are offset by ±110º. Also all speakers should be monopole, equidistant to the listener, and all delay (ms) calculations on the surround decoder should be turned off (0 ms).

For movie surround, the front speakers should be placed at the edges of the screen, toed in to face the central listening location, and the tweeters should be ear height. The center speaker should be placed behind the screen (when using projection) or over or under a TV, and as close to ear height as possible. Rear channel speakers should be placed high on side walls, slightly behind the listening position, and should have a normal high-quality monopolar construction.

See also

Surround sound