Because you are using a shitty software EQ?

Easy to make a filter for two bands - just add another EQ circuit in series. It gets hairy very quickly though.

I typically use whatever EQ my favourite sounding media players come with.  Perhaps the advanced ones sound just as good as hardware eq.

There is an aversion to all forms of EQ in high-end audio for reasons not well documented, the only transducer I know of which has attempted to 'fix itself' with an included proprietary equalizer is this one http://www.dsp-earphones.com/

If you're an iOS person, I'd be very interested to know what you think of how they sound actually.

Sorry for the off topic.

No measurement rig but I'm pretty sure they work alright with an open back, maybe with a little more (paper) damping at the back of the drivers to lower the bass distortion, though I'm not sure the gain in resolution and air would be worth the loss in isolation. Try for yourself, I find the change kinda subtle with my rig.

stratocaster mentioned the hm5 pads should fit, they are comfy and generally sound good wherever you put them.

I put on my rotting SR-80s for shits last night and they sound decidedly low-fi and wonky in comparison. It's not all rosy, though, these are not up to par with $150+ open cans (hehe), I A-B'd again against some old DT990's and while I enjoy listening to these more than the beyers, they do not quite match up in some ways. I know the comparison is kinda unfair but I don't have any other closed cans handy.

If you are sensitive to treble issues you most definitely will want to take care of that peak, while not wholly bothersome and fatiguing like the Beyer treble, it does turn out to be distracting with certain kinds of music. Also, if you find the midrange somewhat veiled or the voices a little too back in the mix or not well defined, you will want to boost around 3 KHz because these are barely DF EQ'd. I cannot stand headphones tuned to the recommended 12dB peak, but a 3-5 dB boost I do find beneficial with these.

Have fun!