People need to take into account the personal preference of the individual and the preferred listening level when they come up with blanket statements that a certain can is useless for a certain music genre. I am sitting here and am having a blast listening to metal on my DT880s (2006 edition). How can this be?
1. My current listening level is IMO quite loud, probably enough to escape the most of the Fletcher Muthcingson curves and give the sound a more forward nature
2. The DT880 is a fairly bright can which downright rules when it comes to for example cymbals
3. The soundstage is good and large which almost makes a drum solo a bit eerie as it moves in the soundstage as different drums are hit.
4. The ruler flat, clean and very extended bass does not intrude on (and cover) the mids where the electric guitars reside. This is certainly a matter of personal preference, but IMO metal, which tends to be more melodic in its character than rock ( if you listen to metalcore and other "metal", this does not apply) rests on the guitar lines. Sucked out mids kills them in my eyes.
In the end ALL of the frequencies matter in a certain way. The bass provides a body and a lot of the headbanging factor, the mids contain the majority of the musical content while the highs are needed for keeping up the life in the music (see the general complaints on how the HD650 performs with rock, which is the very reason to why some like them for it). It is more a matter of which drawbacks from recessing the different frequence ranges that you are more willing to accept. We could also bring soundstage into the equation, some perfer the typical grado sound stage, some others dislike it and want a less forward one.
Of course, if you want a headphone for listening to mostly metal and rock on lower listening levels, just forget it, this is NOT the best alternative. If you worship the allmighty bass, then feel free to continue to do it and get another headphone that might satisfy you, while I am satisfied with what I have and continue to worship the mids. I played around a bit in foobar and applied a "V" curve on the EQ which supposed to yield the best results with heavy music. I hated it, it was as if there was no energy in the sound.
NP: Judas Priest - Painkiller
*headbangs as much as is possible without having the cans fall off my head*