I my experience it's always luck of the draw which happens to resonate well and which not. You can find a guitar made of plywood that resonates like crazy and sounds just awesome unamplified, in fact many guitars I've had or played have proved that it's nothing to do with tonewoods how the guitar resonates etc. that's all simply marketing hype etc. that guitarists believe without any prejudice. Hands down the best resonating and acoustically powerful electric guitars I've played were made of spruce and paper/wood pulp resin-hardened material called flexwood, or cheap basswood.

The Epi Korina SG, like the V and the Explorer is made of 'industrial mahogany' a.k.a. 'mystery wood' in some circles, i.e. they're made of several pieces of some leftover wood and laminated with a thin veneer of African mahogany or 'korina' to make them look two-piece...so the body wood certainly isn't what gives them a nice acoustic tone. The neck wood is also rather soft mahogany compared to what Gibson uses, so it's not there either.

That said, they ARE exceptionally well made and it really requires pretty much a microscope or tearing the guitar apart to notice all the seams and how it's constructed - for instance most SG's of the line also have a bound neck but few users even realize that, it's so seamlessly made and the binding is rosewood as well. And they are very nice guitars, I had a '58 Korina Explorer and it was better made than the Gibson equivalent, but the Gibson had more stable woods and, real solid woods and no laminates. That didn't affect the sound any, though. I myself didn't realize they're laminated until I ripped it apart when modding it and drilled a few holes into it....and then I read up on the subject a little more from Wikipedia etc. but they're so well put together I think not a lot of people ever realize they are made that way.

I'd love to get one of those Korina SG's myself...the Explo was a real nice axe.