Describes the radiation pattern of sound waves from a sound source (the sound source being a speaker in terms of audio/video); definition of the amount of air all around a speaker excited by the sound waves it produces.

Think of a flashlight and the light it gives off. The light angles out to the sides as it moves away from the flashlight creating a larger and larger spot of light. This is the flashlight's dispersion. A laser-beam has a very narrow dispersion (it's light is very focused and does not angle out much at all). A spotlight has a wide dispersion (its light angles out to fill a vast amount of space). Speaker dispersion operates essentially in the same way with sound waves taking the place of light beams.

  Dispersion in speakers is most frequently quoted as an angle in degrees from the center of the speaker related to the sound pressure levels generated at that angle. As you move farther away from the centerline of the speaker, the sound level dies off (just like how the light at the center of a flashlight's spot of light is brighter than that at its outer edges). A speaker with a wide dispersion sprays sound out in a wide angle with the sound being of a reasonable level. A speaker with a narrow dispersion is more like a laser, directing its sound in a very specific area.