In your position, I would speak to the landlord again. As it stands, he might think that he has solved the problem by having a word with the occupants.
I would have thought that as it is a rented property, and if you follow the proper channels of complaint (vie environmental health), the landlord might be obliged to at least fit carpets to minimise the noise.
Worth a try, maybe?
COUNTRY, CITY, AREA, PLACE -Game 21
Elderly fellow gran has become loudly racist