Music suddenly sounds wrong, no dynamics

My first guess is the electrical but it typically comes and goes with the electrical usage. Did this occur after someone recently moved in? If possible try to 'borrow/demo' an re-generator and not a battery back up.

Sorry but what does 'lamps may fall out at times mean'? Sounds to me like it might be gravitational and not electrical.

Given your description, I take it that this is a problem that is constant. Like Xti16 said, if it was a power issue, it would probably come and go. You need to isolate the problem.

Have you made any changes to your system at all? Even if its something very small like changing IC's. If not, still go over your system and check all the connections and make sure everything is as it should be. If your speakers cables are connected out of phase, that could easily be the problem.

My first guess is that the problem does not lie with the Ayre equipment. It may, but I would be surprised. Moving to your speakers, I would suggest 2 things. 1. Go over each speaker and make sure all the screws are tight. They can loosen up over time. 2. Go up close and listen to each one and make sure that whatever the problem is, is effecting both speakers.

Next, I would go the computer. Look at all the settings in the OS and related software and make sure everything is all properly configured. For example, you may be set for 5 channel HT instead of 2 channel stereo. Even if you didn't make any changes yourself, sometimes upgrades can mess up some of your settings. Also, if you find nothing wrong with your PC, I would still substitute it with another source, just to be sure. Hook up a cheap DVD player, or something similar. It doesn't have to be anything high end, you're just using it to check for anything major.

Try connecting your source to a different input on your preamp. Also, if you have any other components that can substituted in the system, just to rule out good components, do that too.

See if any of that helps and then post back.