|
Any stereo system is capable of producing surround sound with a little extra hardware. All you need is an extra pair of speakers and some wire. That is all you need for surround sound because your stereo is already playing the rear channel. This article will show you how to hook up speakers that will play only the rear channel.
This is known as poor man's surround sound). It is different from
real
surround sound because it lacks the center channel and the rear channel is played in the front speakers - Although, it is supposedly unheard (more about that later). It is similar because the rear speakers play the audio encoded for the rear speakers. Thus, it is an inexpensive way to add depth to your music or movies.
|
|
This is the schematics for a poor man's surround sound system. Notice how simple it is to implement. The front speakers are hooked up just like normal. The rear speakers, however, hook up to the positive stereo terminals only and the negative inputs of those speakers are simply wired together. Some people suggest putting a resistor in series to one of rear speakers to reduce the rear channel volume. However, on my system, the rear channel barely plays loud enough. If the rear channel is to loud, I prefer turning the speakers to reflect of the back wall or hide them under a table.
|
|
|
How it works -
Surround sound encodes four sound channels (left front, right front, center and rear) that are encoded into a two channel stereo signal. The left front audio is recorded in one channel and the right front channel is recorded on the other. So, any stereo will play these channels just like a surround sound system. However, surround sound also has a center and rear channel encoded into the audio track that can't be heard when played be a two channel stereo. It is a bit tricky how it does this so pay attention.
The center channel is recorded on both the left and the right channels. Thus, when a two channel stereo plays the surround sound encoded audio, it creates the illusion of a third speaker between the left and right front speaker (but it is not very well defined). A surround sound decoder can detect the common data in the two channels and removes it from the left and right front channels and plays it in the center channel.
The rear channel is also recorded on both the left and the right channels. However, they are recorded 90
°
out of phase. Thus, when left speaker pushes out to play the rear channel sound, the right is pulling in and vice versa. This effectively cancels the sound wave for the rear channel before it gets to your ear! Of course, a surround sound decoder can detect the similar data that is 90
°
out of phase and direct it to the proper speaker.
But, how does the simple wiring shown above decode this rear channel? It's simple! The rear channel is decoded because when one of the channels is producing a positive charge when the other is producing a negative charge and vice versa. So, when one side is positive, the other is negative. Thus, creating a circuit for the rear speakers.
|
Help
Search
Shop
