[miercoles]

firstly, hello!  i'm new here, but i've been pouring over these forums for days!!!  too many hours have been spent on this search.
 
i'm looking for headphones that are somewhat flat, but that also represent some sub - at least as low as 10hz... its a tough thing to find without coming across tons of basshead stuff (which I FULLY appreciate).  i'm a bit of a bass head myself, but i want something with some accuracy.  ....something I could at least reference mixes on, but also hear sub.  I make BASS music, but like I said, I want to avoid "enhancements" as much as possible.  
 
looking in the $300 range...
 
I'd would soooooooo appreciate help in ending this journey!

 

[KG Jag]

Maybe the HE 400 at its current closeout price.  The D2000 is discontinued and even used ones are a bit--or more--outside your budget.

 

[Claritas]

I haven't tried yet tried HP50, but charts and report indicate that it might be what you're looking for.