Thanks for the replies. Sorry about posting in the wrong forum, won't happen again.
@silas - the setup is over two years old and it's highly unlikely the client will plump for a new purchase. To put it into perspective, we haven't been fully paid for the original contract and the client has not opted for a maintenance contract either. Not because they don't have the money, but because they're penny-pinching. Due to certain other influences we are unable to push them aggressively for payment or anything else.
@Charlotte - that is exactly what is happening. The Waterfalls are not built to take an aggressive amount of power, they're architectural speakers. They are installed in a very formal living area so I guess the original installer had no idea that they would be trying to rock out. There is an actual dance floor with appropriate equipment installed, it's just that they party close to the bar where this setup is.
@Jason: The customer will 'pay' for a reasonable amount of work. They are whining incessantly about the setup, it's over two years old and obviously issues keep cropping up due to careless and aggressive handling. They are also extremely unpleasant to deal with - we really have no choice but to service their needs because a very large chunk of our corporate contracting is tied to the commercial area they own and rent out to large companies.
And, they don't 'go' to work. They don't need to
I am pretty sure the client will want to retain the architectural look of the Waterfalls. The question is how to fix the consistent blowing issue, and I thought of the lightbulbs. I also thought of reducing the output level on the preamp (it's a NAD pre with a variable pad on one of the outputs, I can cut up to 6dB). Maybe both, but I don't want to have him crank it up even more. Or maybe a smaller amplifier for the room.