The ES821EB by ESMOOTH, they are exactly what you're looking for, big open sound stage, crisp natural highs, neutral clear midrange, and totally accurate bass. I've spent over $1200 on seven different pairs of headphones looking for perfection and these are the best of all of them, there is no need for me to spend any more looking for better ones, these are as good as it gets regardless of price.
I have checked out all the Sennheiser range and many others, none of them match these. I was an obsessed nut finding fault with everything i bought, listening critically for hours and comparing, i even have a pair of Sennheiser 449's right here in front of me and in an A/B they do not compare with these ESMOOTH (No i don't work for the company, i'm just one hell of a happy customer) I had never heard of ESMOOTH before, but i stumbled across them in a boutique Apple Mac store and initially thought "Here we go again" but wow, i am finally happy, and i'm sure you will be too. ESMOOTH is a high end specialist headphone company in China providing drivers for companies all over the world, but their own range is simply superlative. These things are so accurate it shows up a bad mix, whether i'm listening to Michael Jackson, Celine Dion, Whitney Houston or just straight out hardhouse, these headphones nail it every time, extremely well balanced, i have A/B ed them with all the Beats Audio range plus multiple $500 Bose models and they all seem sadly lacking compared to these, trust me you won't be disappointed, if you simply want the truth/accuracy and nothing but the truth/accuracy i highly recommend these, cheers. Just know that brand new they are ever so slightly sterile sounding until breaking them in, i found 30 hours use was sufficient to bring the best out of these babies, they keep improving sound wise the more you use them up to about 50 hours use.