[ziphyx]

Hello all,
 
I lately mix music quite a lot and I use my v-moda m80 for it as it is the best headphone I own at the moment. Although I would like to use a headphone with a more flat response. I read a few threads about this and I'm kinda interested in the AKG models. 
I'm also using a Focusrite 2i2 as interface for mixing. The music I mix is mostly guitar (both acoustic and electric) and vocals. Thats why I prefer a flat response headphone. Though I'm wondering if I should be using something else besides this interface, for example when I get a high impedance headphone. 
My budget is around 250$. Thanks in advance

 

[Schonen]

Shure SRH840
 
http://www.youtube.com/watch?v=QJh8B1QfEn0 <it's in 5 parts.
 
In the end he settles for Denon AHD2000 but SRH840 are in his last three picks and he does own SRH840 and use the 840. SRH840 is flatter than Denon AHD2000 though so not sure why he chose Denon in the end. Denon are bassy, maybe it was the fact Shure uses a coiled cable and he doesn't like coiled cables much.

 

[Claritas]

  In the end he settles for Denon AHD2000 but SRH840 are in his last three picks and he does own SRH840 and use the 840. SRH840 is flatter than Denon AHD2000 though so not sure why he chose Denon in the end. Denon are bassy, maybe it was the fact Shure uses a coiled cable and he doesn't like coiled cables much.

 
 
I enjoyed that whole series. He's not quite scientific about it, but he tries. In the end, he simply liked the look and feel of the Denons. I completely agree with him about their fit, but I undoubtedly prefer the sound of the Shures.
 
Note also that D2000 with stock pads isn't isolating. SRH840 isn't flat, but it's flatter than many. Some find the headband uncomfortable, so you might need to mod it. (Boy, you're getting me thinking: Shure drivers in Denon cups!)
 
I'm supposing that OP means K271mkII and K550; I haven't heard them yet.

 

[Schonen]

Yea, the SRH840 are a bit heavy on the head. Out of all the headphones I have ever owned the SRH840 is the flattest. Drivers hold up real well for electric guitar practice too, bass and six string.
 
OP, here are data sheets for various headphones so you can compare frequency response and look for a flat response curve.
 
http://www.innerfidelity.com/headphone-data-sheet-downloads