Dolby Pro Logic II is a sound-processing technology developed by Dolby Laboratories that matrixes multiple audio channels to produce advanced sound processing effects. This technology is widely used in most of today’s audio-based electronics. This includes game consoles, audio/video receivers, and home cinema systems, such as Nintendo’s GameCube, Sony’s PlayStation 2, and Wii. It is also used in high-end audio installations. Unlike Dolby Surround, which only decodes the rear surround channel, Pro Logic II also decodes the centre channel.
It was originally designed to decode Dolby surround and stereo soundtracks for analogue cinema systems. The Pro Logic II technology was introduced in 2000 as an adjunct to the previous Pro Logic technology used widely in consumer electronics and cinemas. Dolby Pro Logic II improved upon the consumer-based Pro Logic technology by offering many distinct advantages over older Dolby technologies. These advantages included:
- 5.1 channel surround sound support.
- spot effects with video game play.
- stable and precise audio placement within the listener’s audio environment.
- surround sound playback in every modern audio/video receiver, home cinema system, and powered surround sound PC and game system.
Installations featuring Pro Logic II technology utilize three front channels, two rear channels, and advanced steering logic that controls the output volume of each channel based on the direction of the reproduced sound.
Pro Logic II also offers two additional flavours: Pro Logic IIx and IIz. These enhanced versions of Pro Logic II technology enhance the realism of the listener’s audio environment by providing additional channels that expand the spacial field and precision within assigned sounds in the audio sound stage.
IIx technology up-converts traditional two-channel sources, Dolby Stereo Sound, and Dolby Digital 5.1 encoded sources to 6.1 or 7.1 surround sound.
IIz technology expands IIx capabilities from 7.1 to 9.1. These additional channels are in the form of added front height channels. These added channels are placed above the listening area to extend the sound field from being only around the listener to also originating above the listener. These extra channels are frequently assigned ambient sounds, such as wind and rain.
Pro Logic II technology is found in every modern high-end installation and home cinema system. It can be decoded by any Pro Logic source.
- High Definition sound Formats: Dolby TrueHD and DTS-HD Master
- Digital Sound Formats: Dolby Digital and DTS