Bass is somewhat similar - except the HD600 has slightly more of a mid bass rise. Follows similar pattern though - I actually quite like the bass (bit more extension and to me it would be perfect). Big diff with the HD600 is that it's pretty flat right (comparing raw to raw) through to about 4 kHz, where it starts rising. Thats why some engineers use it for checking a mix. The bump at 1-2 kHz brings the mids quite a bit forward. I actually said to Bob that if it was me, I'd try and dial that back a bit. It's a bit too early for that bump - and hits fundamentals rather than overtones. I found it a tiny bit fatiguing after a couple of hours - was much better EQ'd out a bit.
Again though - I'm just one data point. I didn't like the Campfire Jupiter. Others rave about it. They're heading off to Vince later today and we'll get his feedback. Then Bob will evaluate and either adjust, or not. He also knows what he is after - and that may not match what I prefer.
Where they are now, the remind me a lot of the Oriveti Pinnacle - but without as much bass, and a bit different in the upper mids. Same forward signature though.
You guys definitely shouldn't take too much of this to heart though. Bob has a very good base to work with. I like the basics of what I'm hearing. The rest comes down to tweaking - to get the end result perfect. Discussions so far with Bob tell me he's super confident he can get something almost everyone will like.