A couple of years ago we had a power surge from a storm. Everything that was plugged into a AQ Niagara conditioner(s) were fine. However, 2 rear JL subs were plugged directly into the wall was damaged. BTW, the front JL subs that were plugged into a Niagara 1200 were unharmed.
So, today all of my equipment, including all 4 subs are plugged into Niagara power conditioner.
BTW, I do have a whole house surge protector, but they do not protect against high/low voltage.
ozzy