If I have just 2 speakers and a subwoofer, will I hear a difference with Dolby Digital 5.1 as opposed to Dolby 2.0 surround? Or will the 5.1 sound just like the surround? I am a purist, so I prefer 2.0 to 5.1 even on a 2 speaker system. But I do notice that 5.1 is louder than 2.0, which I like. As a purist, does it matter for me which type I should choose?

It really doesn't matter which one you use as you will only get 2.1 (2 sattelite speakers and a subwoofer) output. Your system is basically outputing a 5.1 mix to a 2.0 mix. Either one is fine.

Thanks. So I will get the EXACT same output (i.e. no audio enhancements/tweaks, etc) with 5.1 as opposed to 2.0 even tho I DO notice that the 5.1 track is louder?

If it's available, I think 2.0 mixes are generally preferable if you don't have a 5.1 system. When 5.1 mixes are downmixed to two channels, the dolby digital decoder applies dynamic range compression and other post-processing such as dialogue normalization.

You won't get the same exact results but either results are acceptable (in my experience). It doesn't matter which one you use, you will get a 2.0 output. However, the 2.0 signal might sound clearer or the 5.1 might sound clearer. From my understanding, you could have a couple of things going on with the 5.1 signal:
1. It is being downmixed to 2.0 thus meaning that certain sounds that should only play on the left back and right back are being played on the left front and right front. You could also be using the Dolby to downmix to a 2.0 signal which means you are only getting the left and right (along with the center) channels and nothing more.

2. Since you are using a 5.1 mix, the left back, right back, and center channels are just not being sent through your sound card to your speakers.

I am not really sure what the capabilities of your soundcard are or what software you are using to playback the DVD.

NO, DVD players (software) can downmix all the 6-channel into 2, including the "thump" channel



I'm not sure whether the 2.0 DD track preserve the full dynamic! If it were 5.1, you can also choose whether to preserve the full dynamic range, of course , the speech part will be very soft and when there's background music, explosion, it will be as loud as thunder!!

You better use the 2.0.
If you don't have a downmix from 5.1 to 2.0 you will loose 2/3 of the signals. Otherwise if you do have a downmix you may have some phase problems. So better use the 2.0 mix which is optimized for a stereo listening.

well, actually a DD decoder will do all that to any ac3 presented to it. that's why good decoders allow you to turn DRC off (dialnorm is part of that - it's the same process).

DRC is useful if you're cooking and can't hear the dialogue. or if you like to watch DVDs late at night but have neighbors