From Rick Altman, "Television/Sound" in Studies in Entertainment: Critical Approaches to Mass Culture, ed. Tania Modleski, Bloomington: Indiana U. Press, 1986. 43

The auditor must be convinced that the sound track provides sufficient plot or informational continuity even when the image is not visible. For example, it must be possible to follow the plot of a soap opera from the kitchen -- or the score of a football game from the bathroom. 42.