Encoding into Dolby Pro Logic

Dolby pro logic is an easy way to output 6 channel audio from a 2-channel soundcard with degraded but useful results. Rudimentary Dolby pro logic encoding can be achieved with usage of some effects.

1. First, create the front left and right channels. Create 2 audio tracks, each carrying either the left or right channel. Pan the left channel to the left and the right channel to the right with the pan control.
2. Now create the rear left and right channels. Create another 2 audio tracks as above – the left channel panned left and the right channel panned right. Then apply invert audio to both new channels and the signals will come out of the rear speakers.
3. Next, create the center channel by creating a single audio track with monaural audio from a different source. Center it with the pan control and the signal will come out of the center speaker.

• If a copy of the signal in the back speakers is desired in any single front speaker, the signal in the back speakers must be delayed by at least 0.05 seconds and a single new track should be created. Pan the new track to orient the signal in the front speakers.
• If the same signal is desired in all the speakers except the center speaker, delay the back speakers by 0.5 seconds and delay either the front left or front right by 0.2 seconds.
• If you want to hear something from the subwoofer, create a new track, select a range, drop a synthesizer effect, and set the frequency below 60Hz. The subwoofer merely plays anything below 60Hz or so.

Other tricks you can perform to separate the speakers are parametric equalization to play only selected ranges of frequencies through different speakers and lowpass filtering to play signals through the subwoofer.