I'm assuming you have Sennheiser HD600 headphones. Those are a high quality full-range headphone and will produce a range of frequencies far beyond what ANY (not just Q100) bookshelf speakers can produce. It's just not a fair fight.
Have you removed the port plug for a little more bass response? Assuming you have, your seating position and the physical location of the speakers, the room acoustics and whether or not you are using a subwoofer all play a part in how your speakers sound. I'm sure they are working correctly, it is probably a matter of those conditions which could afford getting the most out of them. How about a photo of the installation and a sketch of dimensions? What kind of space is it, and what kind of floors, walls and furnishings are there to affect sound?
KEF R500, R200C, R100, SVS SB2000 sub, NAD T758 receiver, Pro-Ject RPM1 TT w/ Ortofon 2M Red, Bluesound Vault2, Sony BDP-S480 BlueRay player, Samsung UN55JU6500F 4K LED TV, KEF M500 headphones, Sony CDP-CE500 CD changer.