AC3
AC3---The Next Generation
| ¡@ | The release on laser disc of clear and present danger and true lies in |
| ¡@ | early 1995 heralded the next step in home theatre sound, Dolby Surround |
| ¡@ | AC-3. These titles, with more on the way, incorporate a new digital sound- |
| ¡@ | track with five full-range center, right, left surround and right surround-plus |
| ¡@ | a sixth bass effects channel. Because they provide a regular Dolby |
| ¡@ | Surround track as well, these discs are fully compatible with all playback |
| ¡@ | systems. |
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| ¡@ | Dolby Surround AC-3 decoders will also incorporate Pro Logic decoding |
| ¡@ | to play back existing Dolby Surround programs. The formats will coexist |
| ¡@ | and complement each other for years to come, so you needn't hesitate to |
| ¡@ | invest in a home theatre now. Dolby Surround AC-3, for example, has |
| ¡@ | much the same speaker and amplifier requirements as Pro Logic. |
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| ¡@ | If you'd like to prepare for the new format consider a Pro Logic unit de- |
| ¡@ | signed specifically for later upgrading, and/or one of the new laser disc |
| ¡@ | players featuring a special AC-3 output. Whatever you do, however, you |
| ¡@ | can start building a library of Dolby Surround AC-3 discs now and enjoy |
| ¡@ | them in regular Dolby Surround. |
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| ¡@ | What is DVD? |
| ¡@ | DVD is the term which describes the next generation CD-ROM standard. |
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| ¡@ | DVD was developed from the start to be a unified format for movies, |
| ¡@ | audio, and computer storage. DVD disks are the same size as audio |
| ¡@ | CD and CD-ROM disks, which makes DVD players backward-compa- |
| ¡@ | tible with existing CD and CD-ROM disks. DVD was also developed |
| ¡@ | to support future write-once (DVD-R) and read/write (DVD-RAM) disk. |
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| ¡@ | DVD is supported by a consortium of major entertainment, consumer |
| ¡@ | electronics and computer makers, including Sigma Designs, Toshiba, |
| ¡@ | Time-Warner, MGM, Columbi Tri-Star, Microsoft, Sony, Philips, Mat- |
| ¡@ | sushita, IBM, JVC, Hitachi, Mitsubishi, Pioneer,Thomson, and many |
| ¡@ | others. |
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| ¡@ | A DVD-ROM drive installed in a personal computer offers massive high |
| ¡@ | -speed storage capacity of 17 gigabytes, which is over 25 times th |
| ¡@ | capacity of a traditional CD-ROM. The same drive, which looks like a |
| ¡@ | conventional CD-ROM drive, can support standard CD-ROM and CD- |
| ¡@ | audio disks as well. |
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| ¡@ | DVD videos have been released by Time-Warner, MGM and other major |
| ¡@ | studios, and offer much higher video and audio quality than standard VHS |
| ¡@ | tapes, as well as multiple video formats, foreign language sound tracks, |
| ¡@ | subtitles, and navigational menus, which combine to vastly improve the |
| ¡@ | enjoyment of home video. |
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| ¡@ | For all of these reasons, DVD is expected to rapidly replace all CD-ROM, |
| ¡@ | Audio CD, video game and video tape products. |
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| ¡@ | What does DVD stand for? |
| ¡@ | Originally, DVD stood for Digital Video Disk. As the standard evolved to |
| ¡@ | include additional capabilities, its meaning was changed to Digital |
| ¡@ | Versatile Disk. This didn't translate well into every language, so now |
| ¡@ | DVD doesn't stand for anything -- it's just DVD. |
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| ¡@ | How do I upgrade to DVD? |
| ¡@ | Currently, there are two ways to upgrade to DVD. You can purchase |
| ¡@ | a set top player for your television set, or you can purchase a DVD-ROM |
| ¡@ | upgrade kit for your computer, which consists of a DVD-ROM drive and a |
| ¡@ | DVD playback card, such as the RealMagic Hollywood. |
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| ¡@ | A set top player connects to your TV set like a VCR, usually with an |
| ¡@ | S-Video cable With a DVD-ROM upgrade kit, you install the DVD-ROM |
| ¡@ | drive in place of (or in addition to) your computer's existing CD-ROM drive. |
| ¡@ | You then install the DVD playback card in your computer's PCI slot, and |
| ¡@ | run the Setup software which comes with the kit. With RealMagic Holly- |
| ¡@ | wood, you can optionally connect a cable to your television set, so that |
| ¡@ | you can view movies on television set. |
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| ¡@ | About BBE High Definition Sound |
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| ¡@ | In the mid-1980's, BBE sound Inc. Developed the technology to improve |
| ¡@ | the quality of sound coming out of loudspeakers. This patented circuitry |
| compensates for the known characteristics of loudspeakers. The mass | |
| ¡@ | of a speaker voice coil creates progressively greater resistance or im- |
| ¡@ | pedance to higher frequency sounds, thus causing some loss of those |
| ¡@ | higher frequencies. It also takes longer for those higher frequencies to |
| ¡@ | over come that great that greater resistance creating a time lag with a |
| ¡@ | "smear" effect. That's why loudspeakers don't sound the same as a |
| ¡@ | live performance. |
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| ¡@ | This circuitry listens to the incoming signal and, where needed, dyna- |
| ¡@ | mically restores lost high frequency energy. Then, by delaying the mid |
| ¡@ | and low frequencies in a mirror curve of the speakers high frequency |
| ¡@ | time delay, BBE presents to the ear the low, mid and high frequencies |
| ¡@ | at the same moment in time as they would arrive in a live performance. |
| ¡@ | BBE Technology improves the sound from all audio sources. |
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| ¡@ | Surround Sound / Dolby Pro Logic |
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| ¡@ | In the early 1950's, the film industry introduced new wide -screen formats |
| ¡@ | with multi-channel stereophonic sound, at least three channels across the |
| ¡@ | front of the theater, plus one or more surround channels on the sides and |
| ¡@ | rear. This complicated and costly technology was confined exclusively to |
| ¡@ | the movie theaters. |
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| ¡@ | Then in the mid-1970's, Dolby Laboratories introduced a new way to bring |
| ¡@ | multi-channel sound to the theaters. Based on optical, rather than mag- |
| ¡@ | netic sound track technology, this new format used just two tracks en- |
| ¡@ | coded with four channels of information (left, center, right & surround). |
| ¡@ | With special decoders, these channels were reconstructed in the theater. |
| ¡@ | This format became the norm for motion picture sound which provided the |
| ¡@ | key to multi-channel surround sound in the home. |
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| ¡@ | Typical Home Theater Surround Sound Installation |
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