Learn about surround sound

                                                  Learn about surround sound

There are many ways to make and present recordings of music, mono is the simplest method and was the first to be used in the field of audio playback, mono means that all sounds are recorded to one audio track or audio tracks (e.g. , a single circular spiral groove on a record, or a single track on a magnetic tape), then played through a single speaker

Two-channel, that is, the sound is played on the speakers on both sides of the listener, which is what we usually call stereo. But that's not entirely accurate, because "stereo" actually refers to a wider range of "multi-channel" recordings. (The binaural sound format is currently popular in home stereo receivers, televisions, and FM broadcasts.) The simplest binaural recording, also known as "binaural recording", uses two microphones instead of two The ear "gets". When you listen to the playback of these two channels on the speakers, it will reproduce the "immersive" experience for you

"Surround sound" recording takes this idea a step further, adding more channels of audio so sound comes from three or more directions. Although the term "surround sound" technically refers to a specific multi-channel system designed by Dolby Laboratories, it is more commonly used as a general term for multi-channel sound systems such as movie theaters and home theaters

It is possible to record surround sound (by picking up sound from three or more directions) with special microphones, but this is not a standard way to create surround sound. We know that almost all movie surround soundtracks are produced in the mixing studio, which is commonly known as "post". Sound editors and sound mixers record many different recordings, (dialogue recorded on the set of a film, sound effects and sound clips recorded in a dubbing studio or created on a computer) and then decide which "spot" or In which audio channel, this also leads to why having a good monitor speaker system has become a "key" factor that is particularly important in post-production

"Surround Sound" Development History

Over the years, many different "surrounds" have appeared. Disney's "Fantasia" (1941) should be one of the earliest surround-sound films recognized by the industry. This is a film that shows the atmosphere of classical music. Recordings of each orchestral part and mixing them to produce 4 different soundtracks, recorded as light tracks on separate film reels, then shifted panning to achieve the effect. Fade out a sound (for example, a violin melody) from one audio channel while building a sound on another channel. But in the end, this kind of surround sound system didn't catch on because of the need for expensive receivers and related components such as speakers (the necessary equipment is really expensive)

But by the late '50s, many Hollywood sound engineers began encoding in simpler multi-channel formats. Several different theater audio setups emerged from this era, including the famous Cinerama (for panoramic movies) and Cinemascope (for widescreen movies), but most of them use the same basic sound technology. Collectively, these systems are referred to as stereo, or perhaps "theater stereo". In a stereo system, 3-5 channels are responsible for "driving" the speakers, the most common of which is a 4-channel system, including one channel driving the left speaker, one channel driving the right speaker, and one channel driving the Center speaker, one channel drives surround speakers on the sides and rear. There are also some higher-end surround systems, with five independent channels and a surround channel

In a surround system, most of the recorded vocals are placed in the front channels, which gives the impression that the vocals are delivered "face-to-face", and some vocals are also sent to the center speaker for A sound that fixes or focuses the overall soundstage, and the later track (or tracks) are often used to present "effect sounds", such as ambient background noise, etc.

Dynamic Dolby

Like stereo, the original Dolby Stereo® had 3 front channels and 1 surround channel. But instead of using magnetic tracks, it uses optical track technology to achieve clearer sound playback. Dolby Stereo also uses advanced noise reduction technology to further enhance the sound quality. Today, Dolby Stereo is almost the analog sound standard, thanks to its superior sound quality and relatively simple equipment installation

In later versions of the surround sound system, a subwoofer could be connected to handle very low frequency dynamic response sounds (these sounds could be separated from the two tracks by means of a crossover). For example, in the field of film audio, subwoofers are used to create powerful rumbling sounds in theaters, which match the scenes of explosions or earthquakes on the screen, so as to shock the audience. The "subwoofer channel" in analog and digital surround sound systems is sometimes called the low-frequency effects (LFE) channel

With LFE parameter adjustment control panel

iLoud MTM Monitor Speakers

In 1982, Dolby went on to develop Dolby Surround®, a version of Dolby stereo for home theater entertainment systems. In 1987, Dolby introduced Dolby Pro Logic, which added an additional channel for the front center speaker

surround sound decoder

When it comes to surround sound channels, you have to mention receivers with surround sound decoders. The decoder recognizes the phase information and extracts it into a third channel, while the receiver also boosts the channel to the appropriate parameter value and adds a slight time delay in order to balance the sound (surround sound can also be accessed with a standard stereo receiver , since all the information is actually contained in the left and right channels, of course this setup will not give you the same quality surround sound as a real surround receiver)

DTS Digital Sound® (DTS Digital Audio)

In the 1990s, a new type of digital surround sound system began appearing in theaters, which works quite differently from analog sound systems. In an analog recording, sound is encoded as a long fluctuating stream of information. In a digital recording, sound is encoded as a series of 1s and 0s, just like a computer program. This way, you can encode more information in a limited space, resulting in a clearer, more precise audio track. In this sound system, six separate audio channels are encoded onto one or two CDs, and then through the CD player and decoder, these channels can be separated and arranged to play on different speakers throughout the sound system. Like Dolby Stereo, DTS has three front channels and a subwoofer. But instead of a single surround channel, it has separate channels for the left speaker and the right speaker

Dolby Digital®

Dolby followed suit with its own digital format, Dolby Digital®. Dolby Digital is also known as Dolby Digital 5.1® (for five audio channels and a subwoofer channel), Dolby AC-3® (for Dolby's third audio coding design), or Dolby SR-D® (for record the digital spectrum). Dolby Digital has the same basic speaker arrangement as DTS and sounds similar, but it works on a very different system. Instead of recording audio on a CD, the digital information is encoded as tiny patterns in the spaces between the sprocket holes on the film. The idea is that the Dolby Digital Reader lights up the LEDs in this pattern as the film passes through the projector. On the other side of the film, the light hits a charge-coupled device (CCD), the same light sensor used in digital cameras. The image recorded by the CCD consists of hundreds of small spots representing 1's and hundreds of spaces between the gauges representing 0's. The Dolby Digital processor unit interprets the digital information in this image as an audio signal

Dolby Digital Surround EX® works the same way as Dolby Digital, but it includes an additional surround channel. The extra channels are placed at the very end of the audio system (at the back of the listener, usually on the rear wall). Like the front center speaker, it can be used to anchor the sound from the left and right surround channels