With the advent of Dolby Digital, Dolby desired to upgrade Pro Logic to meet the higher expectations of surround sound listeners. The result was Pro Logic II, which provides a discrete 5.1 channel surround presentation from any stereo or mono music or movie source. Pro Logic II is effective for Pro Logic encoded or unencoded VCR tapes, music cds, FM broadcasts or any other program material, and is far superior to original Pro Logic.

a technology designed to create realistic 5.1 sound fields from stereo sources. Pro Logic II has two distinct modes: Movie and Music. The Movie mode, as the name implies, is optimized for movie soundtracks -- where a center channel speaker carries most of the dialogue. Movie mode works best on movie soundtracks that have been mastered in the original Dolby Pro Logic format (which 'matrixes' a 5.1 soundtrack into a stereo signal for distribution). The Music mode is designed to create realistic 5.1 sound fields from music sources that were originally mastered in stereo. Since the vast majority of music is mastered in stereo, Music mode does not expect -- or need -- an encoded Pro Logic signal to perform optimally.

Introduced in late 2001, Pro Logic II provides superior decoding of two-channel music and film sources compared with Pro Logic.

Down-Mixing