How Do I Choose the Best Digital TV Decoder?

Dolby Digital (English name: Dolby Digital) is a next-generation home theater surround sound system released by Dolby Laboratories. The digitized sound includes five signals of left front, center, right front, left surround, and right surround. They are all independent full-band signals. There is also a separate subwoofer effect channel, commonly known as the 0.1 channel. All these channels together are called 5.1 channels.

Dolby Digital

In thousands of theaters and millions of homes worldwide, overall,

TV shows, (digital cable and

Which Speaker Does Dolby Digital Choose?

A: The ideal Dolby Digital playback system requires the same full-band speakers for the left, center, right, and each surround channel. If this isn't too practical for you, make sure that the overall tonal characteristics, or timbre, are the same for all speakers. This is equally important for Dolby directional surround sound systems and Dolby Digital playback. Most speaker manufacturers offer home theater speakers that match their tone. Many manufacturers also offer a combination system with five main channels using compact speakers, plus one or more independent subwoofers that reproduce non-directional bass signals; such a "satellite" system has proven to be a Effective, space-saving solutions.

The DVD player has two digital output interfaces, one is optical fiber and the other is coaxial. My Dolby Digital Decoder has both types of outputs. Which one should I use?

Answer: In most cases, optical fiber and coaxial digital connections work the same. In a few special cases, coaxial cables, especially longer cables, can receive radio frequency (RF) interference from household appliances or nearby high-voltage power lines or broadcast towers. But because coaxial cables are relatively cheap, using them is also a good choice. Note: Some DVD players and Dolby Digital decoders only provide one of the coaxial or optical interfaces. Make sure that the audio equipment you purchase uses the same type of interface.

Why does the Dolby Digital decoder provide latency?

A: Because surround speakers in home theater systems are usually closer to the audience than front speakers, playback of both Dolby Digital and Dolby Pro Logic surround sound requires a short surround channel electronic delay to ensure optimal performance. Sound arrival time relationship. In the case of Dolby Digital, this delay ensures that viewers can hear sound from the surround and front speakers at the same time. For Dolby directional surround sound system, because it has lower channel separation than Dolby Digital, a slightly longer delay time (15 milliseconds more) ensures that the sound from the surround speakers is right in front. The sound of the set speaker reaches the listener. This delay reduces the likelihood that the human ear will be aware of crosstalk leaking from the front channel to the surround channel. Some Dolby Digital decoders also provide an adjustable center channel delay to ensure that viewers hear sound from three front speakers at the same time.

How do I set the surround delay?

A: The time delay in your Dolby Digital decoder is preset to the optimal value at the factory, which provides good results for most home theater system installations. If you want to make more fine-tuning, please refer to the manual of this decoder. Most devices allow you to adjust the surround delay in Dolby Digital or Dolby Pro Logic Surround mode. Because the relationship between the two delays is fixed, you only need to set the delay in one mode. The decoder automatically provides the corresponding delay time adjustment when you want to switch to another method. To establish a proper surround delay for your system, you need to know the distance from your viewing position to the front speakers (A) and surround speakers (B), as shown in Figure 8. Then, using FIG. 9 (Dolby directional logic method) or 10 (Dolby digital method), determine the distance from the surround speakers on the vertical axis in the figure and the distance from the front speakers on the horizontal axis in the figure. The intersection of these lines is the recommended delay time. Many decoders allow you to directly enter the distance value, and then the system will automatically calculate the delay time.

How do I set the center channel delay?

Answer: Adjusting the time delay effect of the center channel is not too obvious, so there is no need to worry about it under normal circumstances. If you still want precise tuning, read on. If your viewing space is not large and the number of viewers is small most of the time, and you can place three front speakers at an equal distance from the viewing area, as shown in Figure 11-a, you do nt need a center Delay (set it to "0"). If your center speaker must be placed side by side with the left and right speakers, as shown in Figure 11-b, and therefore placed closer to the audience than the left and right speakers, a 1 millisecond delay must be added for every 1 foot. For example, if line segment C is 1 foot shorter than L or R in 11-b, the time delay should be set to 1 millisecond. If your viewing area is relatively large and can seat multiple viewers in a row like a movie theater, it is best to arrange all the left, right, and center speakers on a line without using the center time delay. Finally, if it is necessary to place the center speaker backwards than the left and right speakers (without legend), if you can choose the option, you need to select "-1ms" (for each foot gap) delay or "-2ms" 2 feet) delay. If these options are not provided, a "0" delay is used.

What is the "midnight mode" of my new Dolby Digital A / V receiver?

A: Dolby Digital audio tracks have a considerable dynamic range between soft and loud sounds. Replay at full audio level, the effect is very shocking, bringing a real theater-like feel, especially for movie soundtracks. However, at night, the intense sound effects produced by movie soundtracks can make your family or neighbors unhappy. But if you have to "keep quiet," you have to turn down the volume, which will make the conversation hard to hear and you won't hear subtle low-level effects. In fact, what you really want to do is just turn down the volume of the strong sound effect and increase the volume of the weak sound, and keep the dialogue sound at the original level. And all this is what Dolby Digital's "Dynamic Range Control" feature can do. To help you understand this feature, manufacturers of Dolby Digital decoders have come up with names such as "midnight mode" for this feature. However, the amount of compression is not arbitrary, but is preset by the sound engineer and recorded on the track. Some Dolby Digital decoders allow you to choose different compression amounts (for example, 50%, 75%, 100%), while some machines only provide 100% compression when selecting the compression function.