Stereo is a kind of audio signal that is able to separate into two separate channels. Stereo is used because it is able to create an illusion of sound originating from multiple directions. It is certainly more effective at creating this illusion than mono audio that only uses a single channel to produce sound. To produce stereo audio, a set up of at least two speakers is used. They are generally placed across from each other at a set distance depending on the size of the audience, the volume of the audio, and the acoustics of the space the audio will be played in. Stereo speakers also come in many forms. A simple set of headphones uses stereo audio. Movie theaters are also set up to use stereo speakers and so are auditoriums. In fact, today, most equipment that produces audio of some kind at least implements stereo audio. The separate channels of stereo audio are effective because the human ears are designed to try to locate the point of origin of a sound heard in an environment. Two or more channels of audio can produce the effect of fooling the brain into believing sounds are coming from multiple sources. This can give the listener a much more immersive experience. This is not possible with mono sound since the brain can easily pinpoint its source. Separate stereo channels can also be designed to give off the effect of hearing the sound from a certain position. This is achieved due to the fact that the sound coming from one speaker is different from the other. Together, they are intended to give a person the impression of being in the middle of the sounds to produce the intended immersive effect. In the past, this effect was achieved by placing two microphones in a recording studio to record a song from two different positions. The audio recorded from these two microphones would then be used to supply the audio for the left and right stereo speakers individually. This method is still often used. However, today, alternate methods of producing stereo sound using digital programs that can model sound from multiple positions can also be used to produce the same effect.