Since the appearance of stereo (right channel and left channel), the sound quality has been advancing by leaps and bounds. Today, multichannel sound allows us to include several audio channels simultaneously. If in another post in our sound section we talked about surround sound, surround sound, in this one we focus on multichannel systems.
Given the limitations of analog formats, the appearance of the digital format represented a real revolution in audio quality, allowing for example the digital compression of 6 or more simultaneous channels.
To obtain the sound of any medium, we need a decoder , normally integrated in the player. Typically, any player would incorporate an analog stereo sound decoder (two channels). Today the devices incorporate three or more channels (Dolby Suround, Dolby Prologic …). Two things are required to obtain digital quality and multichannel sound:
1.- That the player has a digital output (optical or coaxial).
2.- Have a digital decoder , normally integrated in an amplifier or a power preamp.
It is the way to get more surround sound and better effects. In other words, multichannel sound incorporates six or more digitally compressed audio channels that allow the speaker to enjoy spatial sound.
Analog sound encoding types
As we said before, the appearance of stereo sound represented a revolutionary change by allowing the integration of two channels or audio sources in the same analog support . The limitation of the two channels has long been overcome although the majority of the players are still only stereophonic.
- MONO:one channel analog sound, used basically to reproduce any sound. It is used in radio (medium wave and short wave).
- STEREO:two-channel analog sound (left and right). It is the standard format on all current audio players and FM frequency radio broadcasts.
- SURROUND:Also called surround sound, it allows us to have the spatial sensation with a third channel that is filtered from the only two real channels (left and right).
Dolby 3, Dolby PROLOGIC, DOLBY SURROUND are registered trademarks of DOLBY labs that reproduce this type of analog sound creating a spatial feel with up to 5 speakers, but only 4 audio channels. The Pro Logic system projects dialogue directly from the center, while music and effects precede from the front and rear, producing an immersive soundscape.
Coding types with digital sound
The conversion to digital format allows us to maintain the original quality of the sound during its treatment. It also allows the compression of the audio without reducing the quality . The progressive improvement in the compression processes has made it possible to obtain digital multichannel sound encodings with a reasonable level of quality and price for the domestic environment. The appearance of this format became popular with the Compact Disc (CD) and later with other media such as MINIDISK and DVD. The multi-channel digital format went a step further, allowing for more powerful surround sound. Of course, you have to change the amplifier and buy one that supports at least six audio channels, along with a digital decoder if the player does not incorporate it as standard.
Surround or surround sound
The various surround sound systems are known generically as surround systems. Home theater systems are the home versions of movie theater sound reproduction systems. For years, the most widely used system in the cinema was Dolby Stereo with its Dolby Surround home version. Later it was improved and called Dolby Surround Pro-Logic. This system has three front channels (L, C, R) and a single surround channel that is played through two speakers. Dolby later created Dolby Digital (or AC-3) and new competitors emerged, such as Sony’s DTS and SDDS.
