Fishing, here is an article about the other conditioner that was referenced in the AudioPrism review. Its long, but read carefully @ Listening Up
the Game is Afoot. The last 3 sentences of the 1st paragraph seem to somewhat describe your problem. The next paragraph talks about positioning the conditioner, and further down shows a picture of a fairly extensive setup.
http://www.soundstage.com/noisy15.htm
I may be grasping at straws, but just trying to help. The best way to determine if the AudioPrism is causing a problem is to take it out completely. Just use something like a heavy duty outlet strip to get enough plugs for everything, and you probably will notice some degradation of sound, but play the system to see if the problem occurs. If it does, well just keep looking for other ideas. At least, this is something simple to do, and I don't think it is something you have tried.
http://www.soundstage.com/noisy15.htm
I may be grasping at straws, but just trying to help. The best way to determine if the AudioPrism is causing a problem is to take it out completely. Just use something like a heavy duty outlet strip to get enough plugs for everything, and you probably will notice some degradation of sound, but play the system to see if the problem occurs. If it does, well just keep looking for other ideas. At least, this is something simple to do, and I don't think it is something you have tried.