I have a speaker that is powered by USB and I have a ceiling mounting bracket for it. So wondering what the best way to power it is? I have power source from the lighting circuit which I can run off. However, I do not want to install a plug or even those plugs with USB on the ceiling as that would look rather silly. Is there any kind of transformer that you can get where you can have mains going in and a USB on the other-end which can then be put into some sort of junction box inside the ceiling?