A term used to describe the degree to which an audio signal is perceived as being all around the listener. The term “envelop” literally means to enclose or cover completely. In audio production envelopment has been adopted to characterize a property of surround sound mixes. For example, a 5.1 encoded DVD video or DVD-Audio of a live concert is likely to incorporate more than the sound of the artist in front of a listener. It would also include the sound of the audience and additional room ambience beside and behind the listener, and in some cases the listener is placed on stage with the artist(s) with instruments coming from all sides.