If volume is reasonable, ie not far above your normal music listening level, no damage will occur as the energy is spread evenly across the audio spectrum w/o transients. So yes, FM white noise is a very efficient way to break in all components downstream from your tuner, incl spkr cables and spkrs when you're away. To lessen the acoustic noise further without having to reduce the volume, wire one of the spkrs out of phase and place the spkrs facing each other: the radiated bass hiss will largely disappear.
