Hi there,
The tenant,even though she is an owner`s relative, is still bound by the sound bylaws of the corporation and the province. Yes view the bylaws and keep pestering the board (IN WRITING PLEASE) to action. They have the power to evict if enough grounds (ie your file full of letters) They will likely not act without this documentation because to force eviction, they need evidentiary grounds to apply with the courts.
You are also able to call police and lodge complaints with the sound being too loud. They can face "nuisance charges". A visit to your local police precinct will enlighten you as to what to do.
As REIN teaches, with anything, be diligent, persistant, consistant, and document for when you go to court (notice I didn`t say `if`)
Good luck
VP