[IzzyAxel]

I'm looking at high end non-IEM portables for an upcoming trip, and settled on the SigPro, but I couldn't put the sound into perspective very well from the limited reviews of them available.  My question is, keeping in mind that I love the HD600, which Sig should I be looking at, and how does the sound compare?  I want a similar frequency response, but I'd like it to be more engaging.
 
If you're going to suggest another closed portable, limit is $700-750, (I'd buy the SigPro used), it has to isolate well, and it has to outdo the HD600 and not be overly bright.  An "engaging" frequency response is good to a point, (read, bumpy FR) but nothing too extreme in the treble department, treble very quickly turns into a metallic ice pick for me when it's emphasized by the headphone. (also, treble ringing is my worst enemy)  I prefer headphones whose FR tends to look like the ELC, like, downward slope from bass to upper mids, and comes back up a bit in the treble.  A smooth response is appreciated, but not necessary.

 

[Leander7777]

I haven't heard the signature djs, but compared the to HD600 (from memory), I'd say the signature pros are similarly smooth, but sound more detailed and clear. The soundstage obviously won't be as big, since it's closed headphone, so if you can look past that, I think you'll enjoy the signature pros quite a lot.