So here's the deal, I'm 16 and I'm into recording etc. I'm a multi-instrumentalist musician but I mainly play guitar. I'm badly in need of good studio headphones with a [more or less] flat frequency response. I want to get the AKG K240s but my mom says she doesn't think I need 60 dollar headphones. (That's the cheapest I could find them for on Amazon.) I've explained to her twice now that I need real headphones because mine suck (Behringer HPS3000) and are shorting out and that good headphones always cost more than 50 bucks. She demanded to see alternatives, so I figured I might as well sign up and ask for recommendations. I need circumaural headphones with a flat-ish frequency response which would be good for studio use and playing guitar with. (I basically never use the speaker in my amp, just headphones.) I would prefer to have a disconnectable cable which is something I've been wanting for a while. Also closed back or semi-open preferably. Something that doesn't let a ton of noise in. (Or out.) It'll have to be under 60 bucks (I know, it sucks) since my mom doesn't quite get that quality headphones cost money. I don't want to have to buy a headphone amp so that's a factor as well, it can't be too power-sucking.
One other headphone I've heard of which I'm curious about is the Audio Technica M40. How do they compare to the K240? Do they have a flat-ish sound signature? Sweetwater claims even the drivers a replaceable which is interesting.
Thanks in advance.