San Francisco — Dolby Labs announced that as of April 13, more than 15 million products worldwide include Dolby Pro Logic II decoding technology.

The 5.1-channel surround sound technology was introduced three years ago and is now used in products ranging from home theater systems to computers. Dolby has since increased the five-channel Pro Logic II listening experience to 7.1 channels with the introduction of Dolby Pro Logic IIx last year.