This sounds like you are getting some sort of electrical or radio interference that your speakers are somehow very vaguely picking up and broadcasting. If you have many electrical or radio wave objects around your speakers, I suggest moving them. It may just be due to the fact that you live a very highly dense radio wave area, around cellular towers, radio broadcast towers, etc.
I'm not familiar with the configuration of your speakers so I do not know how to properly set them up, read the manual and if need be, contact constumer support about any or all of these issues and they will hopefully be able to answer your questions.
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