Dolby Prologic IIx. I understood that it will "create" a surround

[andrema71]

Hi I'm a newbie.

I have a cable tv connected to my receiver via optical cable. Normally the sounds comes as PCM48, so as default the receiver is set to use Dolby Prologic IIx. I understood that it will "create" a surround effect. Is it correct ? Sometimes the sounds comes as dolby digital 2.0 or 5.1. What would happen than ? Should I in the last case (5.1) change the receiver to 5.1 or can I leave it as it is ?

Does the quality will change ?

By the way my receiver is a 6.1 from Sony.

Thanks a bunch

[redwudz]

andrema71, in the future please use a more descriptive subject title in your posts to allow others to search for similar topics. I will change yours this time. From our rules:

Try to choose a subject that describes your topic.
Please do not use topic subjects like Help me!!! or Problems.

Thanks,
Moderator redwudz

[guns1inger]

ProLogic II/IIx is not a replacement for 5.1 if the movie already has a 5.1 audio track. What is does do is produce an enhanced surround effect on traditional Pro Logic matrixed audio tracks, and to a lesser degree standard stereo tracks. Your amp should determine what is best from the input, and play back 5.1 from 5.1, and Pro Logic II for stereo and PL matrixed audio. You should not have to select this manually. However, if you are getting PCM over optical from your DVDs then I suspect you have your DVD player set up incorrectly, and should check the audio settings. For Dolby Digital it should be set to BitStream. The same for DTS.

The biggest differences between Pro Logic and Prologic II are stereo rears instead of the original mono rears, and generally better seperation and surround effects. it won't make a stereo track sound as good as a true 5.1 mix, but it will usually improve the listen experience on a good stereo audio track. (Note : an MP3 audio track on a Divx avi is not a good stereo audio track)

[andrema71]

Thank you all.