Haman with you to understand home theater audio

Since the stereo became popular in the 50s of last century, manufacturers continue to compete to create the ultimate home listening experience. Even as early as 1930s, experiments have been carried out around the sound. In 1940, Walt Disney, in order to let the audience in the visual and auditory completely immersed in his animated works Fantasound (Fantasia) (Fantasia), the use of innovative "magic" (surround sound) technology.

Although "voices" and other early experimental surround sound technology can not achieve full replication in the home environment, but this did not stop the music and movie industry recording engineers to explore the pace, they developed the technology eventually formed today in the world of home theater for everyone to bring joy surround sound format.

Mono sound reinforcement

Mono sound amplification refers to a single channel, single directional sound reproduction. All elements in the recording are transmitted using a combination of power amplifier and speaker. No matter where you stand in the room, you will hear all the elements of the sound (except for the different conditions in the room). For the human ear, the sound, the instrument, the effect, and so on, all of these sound elements are derived from the same point in the space, as if everything is through a funnel to a single point. If the two speakers are connected to a single channel amplifier, the sound will be felt from a point equidistant from the two speakers to form a virtual channel.

Stereo sound reinforcement!

Stereo sound reinforcement is a more open type of sound reproduction. Although it is not 100 percent realistic, the stereo allows the audience to experience the correct sound field.

Stereo processing

The focus of the realization of stereo sound on the two channels. While recording the sound, some elements are divided into the left side of the sound field, and the other is divided into the right channel.

One of the advantages of stereo is to allow the listener to experience the correct sound field of the symphony orchestra, where the sound of different instruments from the different positions of the stage, more natural sense of hearing. However, it can also include mono elements. The sound of a band's vocals is mixed into the two track, so that the singer gives the impression that he is singing in the middle of the left and right channels.

Stereo limitations

For the last century, 50, 60s, consumers, stereo is a major breakthrough, but there are still limitations. Some of the recordings produce a "ping pong" effect, which is due to the fact that the mixing is too much emphasis on the difference between the left and right channels, and that there is not enough mixing element in the virtual middle. And, though the sound more realistic, but because of the lack of atmosphere of sound information, such as field acoustics or other elements, let the stereo with a "boundary effect", namely all voices from the front and rear wall, from the lack of natural reflections or other acoustic effect element.

Four channel stereo

In the late 60s and early 70s, there were two techniques for attempting to solve stereo limitations: discrete four channel and four channel stereo.

Discrete four channel problem

Is a discrete four channel problem, need four sets of the same power amplifier (or two stereo amplifier) to reproduce the sound, and the power amplifier is very expensive (at that time it was the vacuum tube and transistor device of the times, instead of integrated circuit and chip equipment today).

Also, the sound playback mode actually is only suitable for broadcast applications (two FM synchronous FM radio broadcast two channels; each radio show obviously you need two tuner to receive all signals), and the need for four channel disc recorder, this is also very expensive.

In addition, the black tape and record machine is not competent to play four tracks. Although some interesting music used this technology to simulcast (in collaboration with the television broadcast video, audio equipment, the whole part) for the average consumer is still too heavy.

Four channel stereo - a more realistic approach to surround sound

Four channel stereo format, using a more realistic and more economical than the discrete four channel surround sound reproduction method; it is the information of the four channels encoded by the matrix for the two channel recording. The practical result is atmosphere of sound or sound effects can be embedded into the two track recording, which can be restored by a common phonograph, and let the sound signal to the receiver with four channel stereo decoder or power amplifier.

In essence, the four channel stereo is the forerunner of today's Dolby surround sound (in fact, if you have an old version of the four channel stereo device, you can find that they can decode most of the simulation of the Dolby surround signal). Although the four channel stereo promised to surround cheap solution into the family environment, but because of the need to buy the loudspeaker amplifier and receiver, additional new hardware and software manufacturers, as well as in the standard content of the program and ultimately failed to reach an agreement, the four channel stereo sound at the end point before, had run out of fuel.