Depends a lot on the headphones, you know. The ones that came with my N800 were ear-murdering hockey-pucks anyway; if the N810 ones are the same, then you and others you're comparing with probably have different aftermarket headphones...

N800 here;
I've got a pair of gfm (= el cheapo) noise cancelling cans, and I can blast my ears out easily, should I want to. I also have no trouble inducing clipping in my car stereo with a cassette adapter, but then again, it clips listening to FM radio at top volume. I think its volume control goes to 11 but the output amp can't handle it. But there's no numbers, so I can't tell. I dial it back to what I think is 9, and all is well.
I can also blast my ear out with the BT headset I use, but that's obviously irrelevant.