Well I've tried to lower the bass and up the mids in the M50s and It kinda worked but the bass still reigned over a bit. EQu has a feature to put it on a "safe" mode and there is no distortion at all. In return though volume is lowered a little. The thing is that not all headphones respond well to equalization i.e M50s. Perhaps the 940s will have some more luck, I hope.
If you push too much the low bass, you'll notice that sometimes the headphone is "struggling" to provide some punch; so you might prefer to keep
the lows subdued . It might be more efficient to eq down the highs, if and only if they annoy you. I don't think the srh940 would sound best out of an ipod anyway.