Harmony seems like a better neighbour than the downstairs person deserves. The loud computer games surely place the man downstairs in breach of the NSW By-law No 1, which states “An owner or occupier of a lot must not create any noise on the parcel likely to interfere with the peaceful enjoyment of the owner or occupier of another lot or of any person lawfully using common property.” Note that there is nothing about the noise coming down, up or sideways – it is just not meant to happen, and there does seem to be the basis of a complaint about what appears to be unreasonable behaviour.