I usually prefer mellow and warm cans for metal, for a couple of reasons. The first being that metal is already a super aggressive genre and headphones that balance it out tend to work better. Both the Beyer DT990 and Ultrasone PRO 2900 are too sharp sounding a lot of the time and kind of take the enjoyment out of listening to metal. Even though I want to have fun with it, I also want to be able to crank the volume up, not be forced to turn it down to avoid getting a headache. The other reason is that metal is oftentimes not a very well-produced genre, and as many of you know so well already, listening to garbage on high-end equipment brings out all of the flaws and makes it that much worse.
I'd say that I prefer the Ultrasones about 20% of the time, and my Brainwavz HM5 the rest of the time, despite them being way less detailed and about a 5th of the cost.
I totally agree. The Grado SR325is were WAY too harsh sounding to turn up the volume (something I'm prone to do). I had some Ultrasone HFI2400, and the mids were too recessed and the highs were piercing... no bueno.
I've found the 'mellower' Sennheiser sound is quite a bit better for my tastes, but I also enjoy DT770 with metal. I had to tone down the bass some though. They don't sound fantastic (really grainy mids and highs, and highs sound pretty artificial), but they do the job. I'll be glad to upgrade whent the time comes