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Dolby Digital Mono This program features a mono soundtrack encoded to an AC-3 bitstream. When played through Dolby Digital equipment, sound will be heard from the center channel speaker only. |
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Dolby Digital Stereo This program features a stereo soundtrack encoded to an AC-3 bitstream. When played through Dolby Digital equipment, sound will be heard from the front left and front right speakers only. |
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Dolby Digital Surround This program features a matrixed surround soundtrack encoded to an AC-3 bitstream. When played through Dolby Digital equipment, sound will be heard from the all five system speakers. The surround information will be monophonic. |
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Dolby Digital 4.0 This program features a discrete four channel surround soundtrack encoded to an AC-3 bitstream. When played through Dolby Digital equipment, sound will be heard from the all five system speakers. The surround information will be discrete monophonic. |
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Dolby Digital 5.0 This program features a discrete five channel surround soundtrack encoded to an AC-3 bitstream. When played through Dolby Digital equipment, discrete sound will be heard from the all five system speakers. |
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Dolby Digital 5.1 This program features a discrete 5.1 channel surround soundtrack encoded to an AC-3 bitstream. When played through Dolby Digital equipment, discrete sound will be heard from the all five system speakers and a subwoofer. |
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Dolby Digital Surround EX (New in 1999) Developed by Lucasfilm Ltd. in conjunction with Dolby Laboratories, Dolby Digital Surround EX (often refered to as THX Surround EX) provides a uniform 360-degree localization. Surround Back Left and Surround Back Right channels have been added to the existing surround configuration of 5.1 channels. Surround EX is still fully compatible with existing 5.1 systems, since the Surround Back signal is matrix encoded with the surround Left and Right channels and outputs them as a 6.1-channel signal. If the surround system supports only 5.1-channel reproduction, the THX Surround EX signal is treated exactly as a conventional 5.1-channel signal and no information is lost. |
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DTS (Digital Theater Systems) An audio format like Dolby Digital 5.1. DTS has its own six-channel (5.1) encode/decode system for movie theaters and also sells a line of DVD videos and DVD-Audio titles that use its compression technique. A DTS Audio track, however, requires almost four times as much space on a DVD disc than a Dolby track. DTS will only play in 5.1-channel sound on a system that has a DTS decoder. Discrete sound will be heard from the all five system speakers and a subwoofer. |
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DTS-ES Matrix 6.1 (New in 2000) With this format, the additional SB channel signals undergo matrix encoding and are input to the SL and SR channels beforehand. Upon playback they are decoded to the SL, SR and SB channels. In addition, the bit stream format is 100% compatible with conventional DTS signals, so the effect of the Matrix 6.1 format can be achieved even with 5.1-channel signal sources. |
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DTS-ES Discrete 6.1 (New in 2000) DTS-ES Discrete 6.1 is the newest recording format. With it, all 6.1 channels (including the SB channel) are recorded independently using a digital discrete system. The main feature of this format is that because the SL, SR and SB channels are fully independent, allowing a better 360 degree sound field. When played with a conventional DTS decoder the SB channel signals are automatically down-mixed to the SL and SR channels, so none of the signal components are lost. |
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DTS:Neo 6 (New in 2000) DTS:Neo 6 applies conventional 2-channel signals to the high precision digital matrix decoder used for DTS-ES Matrix 6.1 to achieve 6.1-channel surround playback. High precision input signal detection and matrix processing enable full band reproduction (frequency response of 20 Hz to 20 kHz or greater) for all 6.1 channels, and separation between the different channels is improved to the same level as that of a digital discrete system. DTS Neo:6 surround includes two modes for selecting the optimum decoding for the signal source, Cinema and Music. |
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Extended Surround "7.1" What about the extended surround "7.1" format? Well, "7.1" is not a true surround sound format. Rather it refers to home theater equipment manufacturers' proprietary implementation of two back surround channels using the same back surround audio signal that was discussed above. Usually, the audio signal fed to the two back surround channels are identical, but some manufacturers may choose to mix some information from the left and right surrounds. Again, these are proprietary implementations that vary across manufacturers and are not industry standards. The use of two back surround speakers fills in the sound better from the rear of the audience than single back surround speaker implementations. |
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PCM This program features an uncompressed digital stereo soundtrack for improved fidelity. When played, discrete stereo sound will be heard from the front right and front left speakers. This stereo can also then be decoded as a Dolby Pro Logic four channel surround. |
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Dolby Surround A encode/decode process created by Dolby that encodes four channels of audio (left, center, right and surround) onto two audio channels, which are then decoded into three channels (left, right and surround). Not as elaborate a sound system as either Dolby Pro Logic or Dolby Digital. |
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Dolby Pro Logic An audio coding system that allows four channels of sound to be encoded into two channels (stereo) and then decoded back into four channels (left, center, right and surround). The extra center channel enables Dolby Pro Logic to reproduce sound more fully than Dolby Surround, though still not as richly as Dolby Digital. |
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Dolby Pro Logic + Subwoofer An audio coding system that allows four channels of sound to be encoded into two channels (stereo) and then decoded back into four channels (left, center, right and surround). The added subwoofer takes all the sound information below a cut-off (80Hz crossover typical) from the front left and front right speakers. |
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Dolby Pro Logic II (New in 2000) An audio coding system that allows 5 channels + subwoofer encoded into two channels (stereo). Unlike Pro-Logic I, Pro Logic II derives its surround output using signal dominance on the original inputs. The surrounds are also full range and are independent Left/Right outputs. DPLII also adds bass management similar to Dolby Digital. DPLII offers two different decoding modes: Music and Movie (simillar to DTS: Neo 6) |
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AC-3 The technical name for Dolby's multichannel digital sound coding technique, more commonly referred to as Dolby 5.1. A six-channel sound coding process (one channel each for front, left, center, right surround, left surround and a sub-woofer) originally created by Dolby for theaters, AC-3 was subsequently adapted for home use and is now steadily becoming the most common sound format for DVD. Data rates for AC-3 range between 384 to 448 kbits/sec. |
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Dolby Labratories, Inc.
Dolby Laboratories develops audio signal processing systems and manufactures professional equipment to implement these technologies in the motion picture, broadcasting, and music recording industries. Dolby also licenses these technologies for use in the consumer electronics industry. Providing the best possible audio for any entertainment environment, including music, movies, television and multimedia, is Dolby's primary commitment. |
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Digital Theater Systems, Inc. DTS develops, markets and licenses proprietary digital audio technology for use in theatrical and consumer audio markets. The company's surround sound technology can be found in most of the premier cinema houses around the world. DTS also licenses its state of the art technology to audio/video and entertainment software manufacturers to create DTS Digital Surround (5.1) products for consumer use. DTS soundtracks found on DVD's usually fall into one of two catagories. Full rate DTS tracks have a data rate of 1536 kbits/sec where as the half-data rate tracks use a data rate of 768 kbits/sec |
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THX A program run by Lucasfilm® that ensures certain minimum standards are being met in the presentation of moving pictures, regarding sound and picture. THX establishes certain criteria, then licenses devices (processors, amplifiers, speaker systems and so on) that meet those guidelines. |
