I have Pioneer SP-BS22-LR Andrew Jones and had great hope for the matching subwoofer SW-8MK2 in spite of the negative reviews on Amazon due to humming noise

When the stereo is not on, you'll hear a slight humming noise, but this doesn't bother us.

Had an issue in that the Pioneer subwoofer had a constant annoying hum/buzz noise any time the power was plugged in.

We had the Polk 10" & it would constantly make a faint hissing noise until finally it wouldn't work at all.

The music itself was unaffected, but the noise was definitely louder than it was at first and growing as time went on

When the stereo is not on, you'll hear a slight humming noise, but this doesn't bother us.