Be very careful ordering the UE Super.fi 5's, dino9832! You mentioned the reference to the HeadRoom article on the Super.fi 5EBs, for Extended Bass. As a fellow 7506 listener and fan, these EB's are revolting!! Tons and tons of bass, over-acentuated in every regard, and yet the bass DOES sounds good. It's everything else thats missing that will leave you shaking your head and ultimately pulling these out and diving back the the comfort of the 7506's.
I have a pair and they are back in their box, ready to be returned. I wish I'd have read a more informative review of these IEMs before making my purchase. I'm exchanging for a set of Super.fi 5 pros, as I have heard these don't suffer the same problems.
It sounds like you're at the front row of your favorite rock concert, covering you ears with your hands. You can feel the bass but the highs and mids are muffled and overridden by the powerful bass. EQ-ing can help some but you'll find yourself driving the mids and highs up to the limit and still something just doesn't sound right. If a bass track could substitute for background music, if IEMs were meant to "fill in the background with some music", if elevator music required an 18" driver to reproduce, then I could call these headphones suitable and fitting for that world. Fortunately there's more to the world of acoustics than frequencies below 250 Hz, but to the world of the Super.fi EBs, there is not.
These were the 3rd pair of IEM's I've tried in a very similar search, dino. I'm beginning to become discouraged and just settle with some Shure E4C's, which as long as you're not really paying attention sound nice. It's a small form factor, I'll definitely give it that credit. Highs and mids are very detailed and articulate but as a whole the musical experience isn't well, musical. Though it is all in personal preference and taste I suppose, given the fact you like the 7506's, for I'm sure the same reasons I do, I can predict you'll be bored with the E4Cs. I suppose bored is better than disgusted, as with the Super.fi 5EB. I'm going to give the Super.fi 5pros a chance this week.