georghemIt certainly shouldn't be against the rules to point out places that sell the exact same item for less. (E.g., Focus Camera on eBay.) But make sure you're comparing the same products. I spoke with a friend at a camera/audio store and $170 is at or below cost for most retailers.
The ones from Focus appear to (1) be an older version, tho have they changed much? (see photos, particularly of the headbands, here: https://north-america.beyerdynamic.com/press/press-releases/press-detail/article/dt-1350-high-output-analytical-robust-comfortable-and-stylish.html versus here: http://north-america.beyerdynamic.com/shop/dt-1350-cc.html ) and (2) Focus is not offering the CC model. Finally, (3) Focus is Focus. At least they have a real store (way out in Brooklyn), but check out their Yelp and eBay reviews (lots of DOA's) (and if having a real store meant anything, Ryther Camera would be killing it). I got my Canon 5D Mark III in a split package deal (where they take out the kit lens, claim the rebate themselves, then resell the lens for a profit) from one such store and haven't had any issues with 10's of 1000's of frames shot. But still...
The headphones from Focus are almost certainly grey market items, so you won't get a USA warranty. If that or any of the above don't worry you, buy away.