Agreed. My M50s do have a noticeable bass boost. Not a ton, but it is there.
I have not heard the MDR-7506, but I've seen many suggestions that it is very close to the same as the MDR-V6. Here's one thread discussing it: http://www.head-fi.org/t/539506/sony-mdr-v6-vs-mdr-7506-there-is-a-difference-in-sound-pictures-too
The V6 is cheaper on Amazon, so I'd go with it over the 7506. Then research the Beyerdynamic EDT 250 pads
. The Sony pads tend to flake and wear out quickly; I thought the Beyer pads made my V6s a little more comfortable.
Have you heard the HFI-680 are good for mixing in your research? The S-Logic technology in the Ultrasones makes for a fun soundstage effect, but I would think it might could get in the way of producing music.
Do you know about headphone.com? Select almost any headphone in their menu, and you'll come to a page with a small frequency response graph. Here is the Sony MDR-V6
. Click directly on the graph, and you can add additional headphones to the display and pull up ones that are no longer in their main menus. Also, check out the measurements download page at innerfidelity
.Edited by cel4145 - 4/30/13 at 11:42pm