Audophiles: What happens when you play 5.1 surround mixes through regular, average stereo system?

I recently acquired those new Pink Floyd immersion box sets of Dark Side and Wish You Were Here. I don't have the equipment (or money) to make the most of them since the DVDs and Blu Rays have the 5.1 and Quad mixes. (Don't even have a DVD player.) Just curious, anyone know what happens or the difference when you play a 5.1 or Quad mix through a regular stereo system? Do you lose the 'surrounding' tracks?

And are quad and surround mixes cool or just an expensive gimmick? I've never heard one, and don't know anyone who a fancy sound system.

they will sound like stereo recordings.

Ah! That was simple. Thanks dude.

Assuming you have your DVD player set to deinterlace the 5.1 mix and only have the usual two L & R stereo speakers set up you will just hear what was intended for those speakers, any information intended for the rear speakers, sub and centre speakers alone will be lost completely, you'll likely hear leakage or panning information entering into the L&R during the playback. So a stereo mix, but probably missing a lot of info, or kinda unbalanced sounding.

I'd like to start a thread asking if anybody does this on a regular basis, I sometimes do it at work. For instance the Fear Of Music 5.1 mix is kinda crazy, iirc Life During Wartime didn't even have the correct (i.e. original) main vocal.

The recent Quadrophenia 5.1 mix (or rather, 8 songs, because that's all they felt like doing) is supposedly a mess. I've read numerous reports of some channels actually being out of sync with others.

Thanks, Sleigh.

How much is lost on regular speakers? Is it that noticeable? Will only audiophiles notice the difference?

They'll definitely say they do.

Would a regular music fan hear the difference? Is it true it could damage incompatible headphones?

what kind of surround is it? dts? prologic?

Seems to be DTS, just whatever those 5.1 cd remasters of classic albums are. Those Steven Wilson mixes are what I'm looking at.

But maybe it's just the dvd bonus disc that has the 5.1, actually that's probably what it is. All worried over nothing I guess.