There are two issues:

1) Likelihood of success by asking directly:
Of course it's higher when you ask in an effective way. I would recommend the framework of nonviolent communication.

2) Costs of asking the landlord before asking directly:
Carol: Dear landlord Dave, my neighbor is to loud.

Dave: Dear Alice, Carol told me that you are to loud.
Alice: Dear Dave, I'm fully within the house rules and anyway Carol didn't even ask me to turn down the volume.

Dave: Dear Carol, is it true that you didn't ask Alice directly to turn down the volume?
Carol: Yes, but....

That's a situation into which Carol doesn't want to navigate herself.