Speakers wont turn down

Check the speaker cables for connectivity. Be sure to securely plug in the stereo jack/s at the back of your pc

Try turning the volume down on your computer or on the woofer itself.

What kind of system is it?
What "power thing" inside what?
It's a good chance its a ground loop issue.  Make sure the power cords aren't wrapped around each other or touching the speakers or running parallel with the speaker wires for more than a couple inches (interference transmitted into the speaker lines audible through speakers).

If they are computer speakers try this: (remember i am doing this from a windows vista) on the bottom right hand of the screen there should be a volume key right click on it and click on playback devices then right click on your speakers and click properties and go to levels and turn down the volume from there and see does that work... hope this helps.

It means that the volume pot is dirty.You need to find a way to get some WD-40 into the pot.This usualy requires that you take the access to the inside off and spray right inside the pot.Once you do this move the volume dial from min to max a few times and it should fix it.

Try playing with the connection, sounds to me maybe the jack is going bad or has a shorted connection. Plug it in and out slowly to see if that's the issue.

DFCVXB

yes,,this is due to electromagnetic interference...
try to keep the accessory speaker as far as possible fro the powerspeaker..this would serve better

i had the first problem and you can probably fix it by turning the volume knob all the way up and down about 20 times. it worked for me. supposedly the potentiometers in the z-5300 get dirty or worn out, somehow this might fix it. for the second problem maybe try plugging it into the laptop and unplugging it again seeing if it goes back to normal?maybe its a problem with the amp?

Bad connections or faulty wires check the wires and the connection of the wires, usually the buzz is a bad earth