Simply put, bassheads are people who like bass. Imo, there are two types of bassheads. The first type just wants bass just to feel it. These are the people who just wear an average pair of headphones that are bass boosted like the Sony XB series, Beats, V-Moda LP series, and other non-hifi headphones/iems. Then you have the other type that's more focused on the quality of the bass along with the quantity, and having a balanced frequency range. Well, quality is prioritized over quantity, but quantity is still required. If the bass quantity is lacking, a bass boost with an equalizer, or the bass boost feature in some amps usually take care of that. These people usually have headphones like the M-100, HE-400, Pro900, Denon Dx000, LCD-x, and other more expensive headphones.
Then, in the minority corner are people like me, who aren't satisfied with the performance of many headphones out there, especially in the bass region, and they have to modify them in order to get the ideal sound. I can't really give you any examples because I can't think of anyone else who is a basshead and modifies headphones to the degree I do. Then again, what I'm doing is basically bringing out the maximum capabilities of the headphones.
Unfortunately, most of the Head-Fi community views bassheads in a bad light, like we only care about bass quantity, and that quality takes the back seat. Actually, I get surprised when people say that some bass-oriented headphones are too much. If anything, 95% of the headphones/iems out there are more bass-lean than anything.
@Mshenay: The bass on the eq setup isn't really that crazy. It starts getting crazy when these headphones are hooked up to the speaker outputs on a receiver with another 10dB of bass added. These headphones take all of it like a champ. When the bass hits, and I bump the volume up, it will make the text on your monitor look blurry, your eardrums will viciously vibrate, and you will have hearing loss if you get stupid with it. I really have to listen responsibly because even though these things are awesome sounding, they can really screw up your ears. I don't know if you can say that about most of the headphones out there. It's truly a dangerous relationship, but that's one of the great things about these headphones. They keep you on your toes I usually listen to them at a low volume, though, but once one of my good songs play, I can't help but ease up on the volume...then I turn it down because my ears can't handle it.
These actually hit harder than some car subs that I've heard in the past. I can say that these headphones outperform the LCD-2 in every conceivable way (assuming my memory serves me correctly).