Two of my Sunfire subs hum very slightly. One hums when I turn on one of my outside flood lights. Since I don't use the outside flood that much, this isn't a real problem. The other is part of my home theater system, and it sometimes starts humming when I'm playing a DVD. Obviously, this is undesirable. Fortunately, I can make the humming stop by flipping a particular light switch on, then off, but the hum sometimes restarts in 10 or 15 minutes (so I have to flip the switch again).
I'm not sure why the hum happens, but I attribute it more to bad light switches than a fundamental problem with the subs. If it really bothered me, I would replace the light switches. (Not there yet, though.)
One of my subs pops sometimes when it turns itself off or on. It's a small pop, but audible. Since it happens only once per listening session, I ignore it. If I wanted a really clean listening session, I would start up some material, have the sub pop itself on, then begin playing my material for serious listening after that. Good luck.
I'm not sure why the hum happens, but I attribute it more to bad light switches than a fundamental problem with the subs. If it really bothered me, I would replace the light switches. (Not there yet, though.)
One of my subs pops sometimes when it turns itself off or on. It's a small pop, but audible. Since it happens only once per listening session, I ignore it. If I wanted a really clean listening session, I would start up some material, have the sub pop itself on, then begin playing my material for serious listening after that. Good luck.