I believe that is true for most Denon cartridges. But the DL-110 and DL-160 have a higher compliance than most Denon cartridges. (a compliance of 14, I think this is due to the fact they are high-output MC carts)
I found this formula, though I'm not sure it is correct:
Resonant Frequency = 1000/[6.28*square root (M*C)]. Where M is the mass of the arm and cartridge and C is the compliance of the cartridge.
If I enter the mass of my tonearm/cartridge and the compliance of the DL-160 I get a resonant frequency of 12,66Hz. Which sits in the 10 to 14Hz range.
But I'm very new to this all, so maybe I'm just stabbing wildly into the dark..