What am i looking for in these graphs? Highs and lows, or an even distribution?
Here is the link of the description of how to read the graphs. When it comes to headphones you do not want a ruler flat frequency, however you don't wan't huge peaks or dips either. The former will be "bright sounding" and the later will be either dull, boomy, harsh, bright depending where the huge peaks and dips are.
From my experience with closed headphones, I tend to prefer closed headphones that have bass roll-off (Shure 440, AKG 271 MKII). While they won't have the bass authority of some other closed cans (AT m50, Shure 840), they tend to sound a bit more natural in that region (less boxy, boomy). Another part of the frequency response that I find critical is a slight taper starting at the 1kHz/2kHz/3kHz. What you don't want to find here is huge peaks in the upper midrange/treble (aka Grado). Grado has is what I call fake detail.
For open headphones however, I like the bass NOT to be rolled off like the closed counterparts. A frequency response like the Beyerdyanmic DT800 600 ohm. Sennheiser models 600 and up.
http://www.headphone.com/learning-center/about-headphone-measurements.php
Good luck. Find a place where you can listen to a variety of them.
