Any unwanted sound considered loud, grating, disruptive, or otherwise unpleasant. In the context of Environmental Sound Design, noise is the enemy of occupant comfort, happiness, and, in work settings, productivity. Due to the popularity of Open Office Plans, noise has become one of the biggest challenges facing architects as they try balance cost and aesthetic requirements with the need to create comfortable acoustic environments (see also Aural Architecture) that are conducive to employee productivity.