Like jjk said, this rig should get loud in a hurry being pushed by the LH1000. It's possible something's up with the cab. I know one member a few years back had a quiet 410, and it turned out that two of the four speakers weren't operating. He re-soldered a wire inside the cab, and BOOM he was back in business.
You can use an AA battery to connect to the speakers and watch the cones as you connect ON/OFF to the battery. All four should move out and then back in, and you'll see in a hurry if you're working with half a box.
Being a sealed design, the Hartke will be less efficient than a ported 410. But it shouldn't be orders of magnitude.
Beyond that, placement, room dynamics, and the volume of your band could be factors. I was driving mine with a 500W amp and it was sitting on a concrete floor. I had to kneel down to hear it when a guitarist cranked up a Marshall half stack to full blast. Part of the problem was that my cab wasn't at ear level, but the other problem was I was hopelessly outgunned with anything less than an 810 and a KW of power on that day.