Surround sound or a two-channel stereo speaker, we are all looking for that immaculate sound where we immerse ourselves in the sonic bliss of a three-dimensional sphere of pure music. We all have been bombarded with advertisements of surround sound system everywhere and it’s very easy to ride on that surround sound bandwagon without an iota of idea what it is all about. Is surround sound the use of multiple speakers where each unit produces a distinct and discrete sound and we as listeners get to “visualise” a three-dimensional musical experience in our living room? Is it just that? But we were told that a two-channel speaker system is also able to do that. Then why all the fuss? Ever since the introduction of Dolby Surround by Dolby Laboratories in 1982, the concept of surround sound has evolved many times over, and with it the confusion regarding the technology too. There’s more to having just multiple speakers in a surround sound system for a theatre-like sound. The different sound formats involved is enough to confound anybody what with names like 5.1, 6.1, 7.1, 9.2, 10.2, Pro Logic Iix, Pro Logic Iiz, DTS, plus a lot more.
Basically, a surround sound is designed to envelop you with the sound all around you – from the front, the sides and behind. It can even recreate sound from the top, from above you. So, what you get is total sonic experience, more suited to provide a theatre-like experience. Most modern movie soundtracks are recorded for surround sound and very little music is recorded in surround sound.
Surround sound configurations
Typically, a surround sound system employs five speakers and a subwoofer. This is the 5.1 speakers configuration – two in the front, two at the back (rear), a front channel and a subwoofer. Three speakers are placed in line with the TV screen, one to the left and one to the right side of the TV and a center speaker. The center speaker is placed either below or above the TV screen. To complete the setup, two more speakers are placed at the back (or side) of the listener. The “.1” is the subwoofer and it completes the system. The idea is to surround a listener with sounds from all directions as suggested by the scene. So, in the movie, if a character throws something, say a stone, the whooshing sound of the stone being thrown at the camera is heard and then continuing behind in the rear speakers. A 7.1 system such as that in a Blu-ray player, two speakers are placed in the front along with a center speaker, two at the sides and two at the back. A subwoofer completes the system. Movies, specially those of action genres are recorded for surround sound and it lets you immerse yourself in a sonic delight suggested by the scene.
Stereo systems, on the other hand, require two speakers only – front left and front right. A subwoofer is sometimes used in addition to carry the low-frequency sounds. Single pair speakers make up a stereo system and it is more suited for active listening to music. It has a more elegant look and does not require much space. So, for an audio enthusiast or a purist, surround sound is for movies and a two-speaker stereo system is for listening to music.
Imaginary music space
Stereo creates a sound-space between and in front of the speakers and this imaginary sound-field mimics a performance stage situated in front of the listener sitting in the “sweet spot” – as if sitting in a theatre. When sitting in the sweet spot, equidistant between the left and right speakers, and far away from the speakers and with the same distance that is there between the speakers, an audio field is recreated. In this audio field or the imaginary stage, the voice of the singer comes right between the speakers (singers usually sit/stand in the centre of the stage). So, one can very much tell where the stage is, where the singer is, and the location of the instruments on the stage.
The difference between a surround sound system is that over and above the performance stage created, it also creates sound to the sides and behind the listener. Thus, when watching a movie, specially of the action genre, in surround sound, you are placed right in the centre of the action being enacted on the TV screen.
Sound outside the sweet spot
When listeners sit outside the sweet spot of a stereo system (when seated not equidistant from the speakers), even though sounds still seem to emanate from the imaginary stage, the location of the sound sources are skewed and biased towards the speaker closer to the listener. However, most listeners are not mindful of the spatial location of sounds and only audiophiles care about such things. In any case, our brain “configures” the location of the sound sources almost accurately even when seated not equidistant from the speakers.
Surround sound or stereo in the listening spot
Stereo or surround sound system is all about manipulating the location of the different sound sources in music or movies. When seated correctly and with speakers placed at right places, a person could identify where that spot is even for a surround system. And in a stereo system, when a person sits correctly inside the sweet spot zone, the system will create effects behind the listener. This, without even the side/rear speakers. Isn’t this wonderful?
The realism of sound
Whether one is listening to surround or stereo music systems, more than the spatial accuracy of sounds, what is more important is the realism of sound and the system’s ability to reproduce it. Does the system produce the exact sound of the instrument? Does the guitar sound like a guitar or does the voice sound like a voice in that system?
More speakers, better sound?
Definitely not. With a right budget, the quality of sound in a stereo system could be better than a surround system. Most people think that surround sound system with more speakers than a stereo system will have a greater audio quality. But the truth is, with the same budget, a two-speaker stereo system, will most of the time, have superior audio quality than a surround type of music system. The recording for music playback is mostly done in stereo. In movies, however, the surround speakers play all the ambient noises creating an imaginary atmosphere. In an action movie (or drama), the speakers play the ambient noises creating a unique realism of sound.
The budget for a surround sound system will be spread over five speakers and sound decoder (for surround effect). In a stereo system, the budget is spread over two speakers only. The budget is available to enhance other quality improving aspects of the components in the stereo system. A surround sound decoder is not required for a stereo system.
The final take
A surround sound system is better suited for movies and the dialogue intelligibility of surround system seems to be better than a two-channel stereo system. For listening to music, the stereo system scores better. So, ultimately the preference of a system over the other depends on the choice of entertainment – movies or pure music.