Techno Tidbits & Problem-solving

Dolby Digital

Dolby Digital is a compression format which records the sound of 6 channels of the theater surround system (Dolby Digital) on the movie film digital track. Of the 6 channels, the sub woofer channel is intended for bass only, and because the frequency range is smaller than the main channel, it is expressed as 5.1 channel.

Dolby Digital is the name of the Dolby surround multi-channel digital system that was developed after the Dolby Surround System and Dolby Pro Logic Surround System.

5.1 channel digital

4 channel analog

surround track

sound track (Matrix)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dolby

Digital encoding

Dolby Digital for movie films

The number of movies made using Dolby Digital since 1992 has exceeded 300 and continues to increase. For compact disc players and laser disc digital sounds, 16 bits are used to sample the original analog audio waveform and sampling is carried out 44,100 times every second. However because an enormous amount of recording signal data is required for the multi channel system with this method, AC-3 is used to compress the data.

In reproducing audio signals, the smaller the bit number used, the lower the sound quality. With AC- 3, drop in auditory sound quality is prevented by using masking technology and digital filtering technology based on the human auditory characteristics.

Laser disc format

Laser discs are now available on the market in large numbers. This means that the recording of different format audio signals on the laser disc raises the important question of compatibility with existing laser discs. Dolby Digital tracks on Laser discs record signals using the space of one analog audio channel so it will maintain compatibility with existing discs and players.

As shown in the following figure, the digital audio sounds of Dolby Digital discs can be played back as currently done. Analog sounds are played back by using the other channel without the Dolby Digital signals for monaural audio signals.

Analog sound

 

Dolby Digital

 

 

(Monaural)

 

 

sound

 

 

 

 

Digital

 

 

 

 

 

 

Video

 

 

 

 

 

 

sound

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

4

6

8

10

12

14 MHz

 

 

 

 

 

 

Frequency

Comparison with Dolby Pro Logic Surround

Dolby Digital is also known as the 5.1 channel system. It is equipped with 5 channels (front left, front right, center, surround left, surround right) in the frequency range from 20 Hz to 20 kHz and an independent Low Frequency Effect (LFE) channel. The sub woofer channel is also called Low Frequency Effect (LFE).

The sub woofer channel can be used as desired to enjoy strong bass sounds.

The table on the next page shows the comparison with Dolby Pro Logic Surround effects.

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Pioneer VSX-D908S operating instructions Techno Tidbits & Problem-solving, Dolby Digital, Laser disc format
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VSX-D908S specifications

The Pioneer VSX-D908S is a remarkable home theater receiver that epitomizes the blend of advanced technology and user-friendly design. Launched in the early 2000s, this versatile component remains a popular choice for audio enthusiasts seeking to enhance their home entertainment experience.

One of the standout features of the VSX-D908S is its powerful amplification system, capable of delivering up to 100 watts per channel across five channels. This ensures that users can enjoy dynamic sound reproduction, even with demanding audio tracks or during intense movie scenes. The receiver supports both Dolby Digital and DTS surround formats, making it an ideal choice for those looking to immerse themselves in a cinematic experience at home.

The VSX-D908S also boasts multiple inputs and outputs, allowing users to connect a variety of audio and video sources. With several composite, S-video, and component video inputs, it accommodates a range of devices, from DVD players to gaming consoles. Furthermore, the receiver features a built-in AM/FM tuner and supports the playback of music CDs, making it a comprehensive solution for all entertainment needs.

Another notable characteristic is the advanced DSP (Digital Signal Processing) technology that the VSX-D908S incorporates. This technology allows for the simulation of different acoustic environments, enabling the user to customize their listening experience according to their preferences. With multiple preset sound fields, including options for concert halls and theaters, the receiver adapts to various audio situations seamlessly.

For those who value ease of use, the VSX-D908S includes a user-friendly interface and remote control. The intuitive layout of the front panel makes it simple to navigate settings, adjust volumes, and switch between sources. The inclusion of a multi-language on-screen display further enhances the user experience, catering to a broader audience.

In addition to its impressive audio capabilities, the Pioneer VSX-D908S also emphasizes build quality, featuring solid construction and reliability. With its robust design, users can expect long-term performance without compromising on sound quality.

Overall, the Pioneer VSX-D908S stands out as a home theater receiver that harmonizes performance, versatility, and user-friendliness. It continues to be a solid option for anyone seeking to elevate their audio-visual setup, making it a notable piece of equipment in the world of home entertainment.
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