 During the "final mix" the re-recording/dubbing mixers, guided by the director or producer, must make creative decisions from moment to moment in each scene about how loud each major sound element (dialog, sound effects, laugh track and music) should be relative to each other.They also modify individual sounds when desired by adjusting their loudness and spectral content and by adding artificial reverberation.They can insert sounds into a three-dimensional space of the listening environment for a variety of venues and release formats