I'm the lucky owner of the two. Unfortunately I don't have any recordings, but here's my experience:
I could try out all the different Diezel cabs with Peter Stapfer (the second "Diezel-boss"). He himself is a big fan of the hempcone box (but then, he designed it ;-)). I wanted to have a 2x12 because it's easier to transport. To be honest, they have almost the same size than the 4x12, but are at least not that heavy. And the best: they sound only very little "smaller" than the 4x12. To my ears, the hempcone 2x12 has a very "big" sound, and it is very "musical". Played by itself, it's got the "nicest" sound of all the cabs I tried. Plus, the audibility on stage is very good, regardless of the volume. That's also what Peter loves best about them.
I can see slight advantages for the Vintage 30 box if you play heavy stuff with lots of palm mutes. There, the hempcones sound a little bit too "broad" for my taste, the Vintage 30 is tighter for this use. Of course it's a matter of taste, and I can play these things convincingly with the hempcone cab. But with a Strat and Single Coils, the Schmidt and Hempcone is my dream sound come true... Hope this helps...
