PCM or AC3 difference?

[ascv]

Need a little understanding, if you can. I never had a AC3 (Dolby) encode on my Trial TMPGEnc DVD Author v1.6 program (ac3 is not available with trial version). My Hauppauge pvr150 card has a hardware encoder onboard and captures from a dishnet 301 reciever.

pvr150 capture is:
Video- Mpeg2, video 720x480, 29.97fps, VBR (constant quality) Max 4400kbps

Audio- Mpeg1, audio layer II, 4800Hz Stereo, 384kbps

I authored my MPEG2 captured movies to VOB files (with TMPGEnc DVD Author 1.6 trial) and then wrote them to a DVD using NERO 6.6. My stereo (onkyo 570 5.1) played the DVD as PCM , not as Dolby. Sounded good, (front rear and sub). Now with the AC3 plugin for TMPGEnc DVD Author (v1.6 retail version) my DVD's play as Dolby Stereo in windows media player v10.0 and on the OnKyo stereo system (5.1).

My problem is, I really dont hear any significant difference between pcm or dolby. Is there any???. I am using the 5.1 optical plugin from my DVD player to the Onkyo stereo.
thanks

[korben_dallas]

The most you'll get out of analog stereo capture is Dolby Surround. So, when you author your movies, you need to specify Dolby 2 channel. This way, when a receiver sees the Dolby 2, it will decode the Dolby Surround imbeded. Obviously, Dolby Surround is not near as good as Dolby 5.1, but it is something.

[falchulk]

You Onkyo probably has a much better dsp mode then dolby stereo. I have a Onkyo 6.1 reciver that can convert stereo into convincing 6 channel sound.

[ascv]

Yes, I think the Onkyo HT-S570 is a great system. Probably why I cant hear a difference between DVD's I made with pcm or AC3. But the quest goes on for knowledge.
thanks