I didn't end up getting the Alpha Dogs. My comparison to the TH600 is on page 96.
From the hour I tried an Alpha Dog for here were the differences I heard
- overall U shaped sound, more prominent treble and bass, however not sibilant like many lower Ultrasone models.
- much more powerful and deeper bass - Alpha dog relatively weak by comparison - the AD is about as bassy as a HD600 from memory YMMV
- fun/energetic and has instant wow factor
- aggressive and punchy, AD was smoother sounding overall
- imaging can sound like its behind you head at times is more 3d to my ears *S Logic at play*
- Smallish soundstage compared to other high end models, but very good seperation
- leaks practically nothing
- easy to power, can be used portably
- snug but comfortable fit
- full lower mids but mine has weaker upper mids where lead guitars, female vocals reside
- some of the best isolation I've ever had on a headphone
- Neutral - trending toward being a little bit bright
- very flat and detailed mids, without any mid bass bump
- Somewhat dryier and thinner overall sound than the DJ
- sounds cleaner than the DJ overall
- seemed a bit more resolving of micro details
- somewhat bigger soundstage and a bit airier
- very complete mids, vocals at no point have any recession from what I had heard
- very very comfortable earpads, headband strap pressure was noticable on my head but no pain
- much heavier as well as being a lot larger
- isolation pretty good but not nearly as good as Sig DJ, wouldn't recommend to use it on the go for size, weight and the fact that the DJ kicks it to the curb for stopping loud noise
I think the AD vs DJ is a very apple to oranges type situation. I'd take the Alpha Dog in a heartbeat for acoustic, classical and Jazz listening due to that superb and very clean / clear midrange. Very much a ideal Neutral sound signature except for a slight treble elevation *which I hear can be cured with the doggie treat mod*. DJ for EDM, Metal (for my tastes), Pop, Rap no contest.