I go away for a half hour and there's a slew of responses. Through all that it appears that JohnMI thinks the LL has no liability, ever. He's wrong, absolutely.
I've been involved in a number of cases where landlords are liable to control certain actions of tenants ... including prostitution, drugs and noise. Yes, the first two are illegal, but noise can also be illegal at times. The legal gounds are nuisance. Landlords are required to abate nuisances. It may not be easy and there are many examples where it's debatable if the line has been crossed. But the obligation is there.
Sure a lot depends on the facts, whether it's plain warranty of habitability or negligence. And yes, while he's correct about the historical context of "quiet enjoyment," he's incorrect about it being limiting.
He also comes from an area that seems to grow militias, libertarians and trolls. The laws there may be different. A predisposition to excuse landlord obligations doesn't cut the mustard.