Mixing individualized media content. When individualized media content is
generated from separate media clips or files, mixing the separate media
clips includes controlling the audio. The volume of the audio in each
clip is determined and normalized with respect to other media clips as
the individualized media content is mixed. This provides a consistent
audio experience even when the media content is generated from multiple
sources having different properties. When more than one track of audio is
present, such as voice audio and background music, the volume of one
track is lowered such that the other audio track is audible. The volume
of the background music, for example, is reduced such that the subscriber
can hear the instructions in the voice audio.