You likely have encountered the phrase Dolby Surround Sound several times. You may have encountered movies in VHS or CDs before that had the Dolby ad at the start. But do you really know what Dolby is? Does it really improve the sounds you hear from your home theater system? How is it different from HD audio? Find out the answers to these questions and more in the discussions below.
What Is Dolby Surround Sound?
Dolby Surround is the consumer version of Dolby analog and Dolby SR, the multichannel analog film sound format from Dolby. As digital technology prevailed, it was eventually supplanted by Dolby Digital. Dolby Surround and Dolby Digital essentially mean an enhanced audio experience by encoding audio in a format that can be decoded later on to be transmitted in multiple channels (multiple speakers) to create a sound that is perceived to “surround” the listener.
In the past, only high end speaker systems had the right processing power to handle the decoding of the different sounds to be produced in different speakers to achieve true surround sound. Nowadays, surround sound is already a common feature for many speaker systems. The Dolby brand (Dolby Digital/Dolby Atmos) in particular is something home theater systems, from entry level to high end, are offering. If you go over various home theater reviews, you will find best home theater system rankings and recommendations that tout Dolby Surround as a highlight feature.
How Does Dolby Surround Work
Surround sound is achieved by encoding sound for multiple audio channel output. The output sounds are then produced through speakers positioned in various locations to create an overall sound output that surrounds the listener. Dolby Surround goes beyond stereo sound (left and right) as it produces sounds in at least 4 channels (front left, front center, front right, and monophonic). The sounds produced in the different speakers of a Dolby Surround system are usually different from each other, creating the illusion of being in the actual scene of what’s being shown on TV as the sounds appear to be come from different sources. This results in a more immersive listening experience.
For example, a concert DVD or Blu-Ray can have its audio output separated into the following: the sound of the vocalist, the sounds coming from the band, and ambient sounds (sounds from the audience and surroundings). This is just a simplified example, though. The encoding of audio files meant to be played in speaker systems that support surround sound may also take into account the movement of the sound sources. The sounds coming from spaceships in a movie, for instance, may be played in varying loudness across speakers to create the illusion of movement. Explosions, on the other hand, are enhanced with the booming sound of the subwoofer.
Surround sound enhances the listening experience as it creates a sense of realism and depth. It’s not just about playing sound (the same audio) through multiple speakers. The audio being played by the different speakers may be also be varied to create a sense of movement and differentiation of sound sources, thereby creating more immersive listening experience.
How to Enjoy Dolby Surround Sound
Enjoying Dolby Surround sound requires three things:
● A media file (video or audio) encoded for surround sound output
● Surround sound speaker system
● The proper positioning of the speakers.
The outputting of surround sound depends on the media file being played. If the media file has not been encoded to output surround sound, you cannot expect surround sound even if you have Dolby Digital or Dolby Atmos certified speakers. If you are playing a video using a “pirate copy” CD or DVD with only mono audio encoded, you will end up hearing the same kind of sound across all your speakers, except for the subwoofer that will always focus on outputting booming lower frequencies.
Surround sound speakers or home theater systems can be in 4.1, 5.1, 6.1, 7.1, or even 10.1 channel variants. These don’t mean, though, that you have to get differently encoded media files. All of them are basically 4.1 channel with more speakers added. The 4.1 channel system involves the following speakers: left, right, left-surround, right-surround, and the subwoofer. The 5.1 channel system adds a center speaker. The 6.1 channel, on the other hand, puts in a rear-center-surround speaker to create a “more 3D sound” effect. Moreover, the 7.1 channel system splits the rear-center-surround speaker into left and right rear-surround speakers.
To properly position your surround speakers, obviously, you need to follow the layout they are intended for. For a 4.1 channel system, for example, the right and left speakers are to be positioned in front (on the sides of the TV) while the left and right surround speakers are placed behind the seats or audience. The product insert/literature that comes with the home theater system you buy should provide you a guide on how to set your speakers up.
Tips on Positioning the Speakers
Consider the following pointers as you position your speakers:
● It is advisable to slightly tilt the front left and right speakers so they aim at the center of the seat or location where the audience will be seated. The same goes with the left and right surround speakers placed behind the seat or audience.
● it is recommended placing the surround speakers a feet or two above ear level (when seated) to achieve more immersive special effects.
● The center speaker can be positioned right above or below the TV.
● The subwoofer can be positioned wherever convenient but if you want to achieve stronger bass sounds, place the subwoofer beside the wall. If you want better distribution bass distribution, put it at the center-front or center-back.
● Almost all of the home theater systems available in the market are good enough in delivering surround sound. Many buyers tend to be unable to notice differences in their sound output. However, not all home theater systems are the same. Some are just better than others. That’s why it helps going over reviews and personally evaluating the audio output of the home theater system you intend to buy.