What exactly is "Dolby Sound"?

                                             What exactly is "Dolby Sound"?

The word "Dolby" in "Dolby Sound" is actually the surname of Dr. Dolby (formerly R.M. Dolby) in the UK. The Dolby Laboratory established by Dr. Dolby has successively invented a number of technologies such as the Dolby Noise Reduction System and the Dolby Surround Sound System, which have directly affected the development of industries such as movie audio and home audio.

1 Dolby Noise Reduction

The debut of Dolby audio technology belongs to the Dolby A and B noise reduction technologies developed by Dr. Dolby in the 1960s that can reduce noise for a variety of audio frequencies. The emergence of these two technologies provided an effective solution for the noise processing of audio equipment at that time.

Also shortly after the emergence of Dolby noise reduction technology, Dr. Dolby established a company called "Dolby Laboratories" in the United Kingdom. Later, the company headquarters moved to San Francisco, California, USA in 1976.

In the 1970s, Dolby Laboratories began to popularize the concept of pre-recorded cassettes encoded with Dolby B-type characteristics, and cooperated with a number of manufacturers to release corresponding equipment. After that, the Dolby noise reduction system slowly opened up one market after another.

In those days, many tape recorders and tapes were marked with the Dolby noise reduction symbol, meaning that the recorder had Dolby noise reduction, or the tape was recorded with Dolby noise reduction.

Of course, generally only a recorder that adopts Dolby noise reduction technology and a tape are used together to obtain better results.

2 Dolby Stereo

In the 1970s, Dolby Laboratories developed Dolby Stereo technology. The technology caused widespread buzz shortly after its appearance, and soon entered the public eye.

We all know that in order to make the audience feel more immersive, many stereo auditoriums are often equipped with a center channel that can enhance the sound effect in addition to the left and right channels, and can create an ambient atmosphere and Surround channels for special effects feel.

However, multi-channel direct recording and transmission is expensive and cumbersome, which has become a major problem for many film practitioners. It is with this in mind that Dolby Laboratories began the development of Dolby Stereo technology.

Simply put, Dolby Stereo technology is to encode and record the audio information of the left, center, right and surround channels into two channels after noise reduction. When the movie is playing, the audio information of the two channels is restored to multiple channels in the opposite way. In this way, the compatible transmission of multi-channel and two-channel is realized.

The epic sci-fi masterpiece "Star Wars" released in the late 1970s used Dolby Stereo technology. The synchronization of the sound direction and the picture changes achieved in the movie's screening in the movie theater brought an unprecedented sense of orientation and presence to the audience, and caused a sensation.

Later, more and more film practitioners also began to use Dolby stereo technology to process the audio of the film.

In the 1980s, in order to enable individuals to watch movies at home with a feeling similar to that of a movie theater, Dolby Laboratories started the transformation of Dolby stereo technology, and successively developed "Dolby Surround". ” system and the “Dolby Pro-Logic Surround” system, and made it into some homes.

The so-called "Dolby Surround Sound" system is actually a home condensed version of the sound system in the cinema, while the "Dolby Pro Logic Surround Sound" system is an upgrade to the "Dolby Surround Sound" system.

The "Dolby Pro Logic Surround Sound" system uses a directional enhancement circuit, which enhances the dynamic and discrete effects of sound, and enhances the sense of sound image positioning, direction, movement, and reproduction of the original appearance of the sound field. This technology is still in use today, but now the number of channels that can be achieved can reach 9.1.

3 Dolby Digital

In 1992, Dolby Laboratories introduced "Dolby Digital". This technology uses a 5.1-channel system with 6 independent channels. The so-called 5.1 is actually the front left and right channels, the rear left and right surround channels and the 0.1 subwoofer channel. Among them, the 0.1 subwoofer channel can emit subwoofers with a frequency range of 20 to 120 Hz.

Among these 5.1 channels, the center channel is mainly responsible for playing the dialogue of characters; the front left and right channels are responsible for playing the sound on both sides of the screen and the part outside the screen; the rear surround channel is responsible for playing the background music And the creation of the entire sound field; as for the 0.1 subwoofer channel, it is responsible for the presentation of bass similar to the roar of machines and space cracking.

After that, 7.1 and even 9.1 channel systems were also introduced. Among them, compared with the 5.1-channel system, the 7.1-channel system has two more pronunciation points, center-left and center-right, and its auditory effect is more complete. However, due to the relatively high cost, 7.1 and 9.1 channel systems are not widely popularized, and the mainstream is still the 5.1 channel system.

Thanks to the "Dolby True HD" lossless decoder developed by Dolby Laboratories, the sampling rate and bit rate of movie audio have also been improved qualitatively. At present, formats such as Dolby 5.1, DTS5.1, THX5.1 are the mainstream of 5.1-channel audio coding. Plus, thankfully, more and more filmmakers have the means to record multi-channel audio directly.

4 Dolby Atmos

Dolby Atmos is a new audio technology introduced by Dolby Laboratories in 2012. This new technology supports up to 128 sound points and is independent of the assigned channel.

The Dolby Atmos system employs an approach to mixing and sound orientation that combines dynamic objects and playback channels. Once activated, it monitors the number and configuration of speakers in a theater or home theater and assigns each speaker the most precise and appropriate playback task.

Under this system, sounds of various natures can be independently generated and mapped to specific locations, striving to maximize the restoration of the live sound.

The Dolby Atmos system can not only bring auditory shock and surprise to the audience, but also greatly benefit filmmakers. With Dolby Atmos, filmmakers can create the sound of a movie without too much concern, and are no longer limited by the number and structure of channels.

5 Dolby Vision

An audio technology company that doesn't focus on video technology is not a good theater operator. Yes, Dolby Laboratories has also engaged in the research and development of theater operation business (Dolby Theater) and video technology in addition to the audio technology of its core business.

In the video technology business, Dolby Vision (Dolby Vision) launched by Dolby Laboratories has received a lot of attention.

At present, in addition to 4K, high dynamic range (HDR) has become an important trend in the development of video technology. HDR formats are HDR 10, HLG, Dolby Vision, and HDR 10+. Among them, Dolby Vision has become the most widespread and commonly used HDR standard on the market.

In early 2020, Dolby Laboratories went on to launch an upgraded version of Dolby Vision IQ, once again taking its video technology and its experience to the next level. I believe that in the future, Dolby Laboratories will bring more surprises to the technological innovation in the audio and video field.