Hi, I have an old sony stereo that has dolby pro logic. I have it hooked up to my pc with 2 regular a/v cords. Im new to surround sound but have a pretty good idea that it works with cds from the cd player on the recever since I can hear out of all the speakers. What I wonder is if the stereo is correctly processing the dolby pro logic when it is connected to my pc. I have downloaded some mp3 files that say they test dolby digital but they do not work correctly with all 5 speakers. So I am wondering if I need to buy anything extra to get my stereo surround sound to work with my pc.
Dolby Surround was invented circa 1977 for the Lucas film 'Star Wars'. The simple system sent LeftMinusRight (the so-called 'difference' signal) to the surround channel, typically two speakers, but one channel. Home-theatre guys in the 1980s quickly figured that L+R gave a 'centre' channel (using perhaps the built-in speakers of the TV monitor) so there you go, home theatre! Dolby Pro Logic is basically the same thing, with enhanced separation Front to Rear (up to 30dB) and a formal centre channel using dialogue-steering logic, and adding the ability to generate test tones. This technique decodes channels matrixed into a standard stereo audio signal, L & R. So any stereo music will give a pleasing effect with ProLogic playback. (Getting to the point) Dolby Digital is a whole other thing! A discrete system of 5 channels plus a dedicated Low Frequency channel = 5.1 Notably, there is 100dB+ separation between all channels (including L & R surround). 5.1 audio isn't mixed down into L & R like before, and I am unfamiliar with Dolby Digital MP3s. So basically just play everything through your Sony and enjoy the surround channel! The centre channel is optional, recommended only for viewing films, and might seem to reduce the L to R separation in music. If you have a nice (shielded) centre speaker, then WTF just place it close as possible (above or below) your monitor, and enjoy! Tip: run your test tones and adjust the C channel volume so it is subtle, not overly dominant. Regards
