Swan M200 loud hum in right speaker

I just turned on my Swan M200 speakers today, and I noticed that a loud hum was coming out of my right speaker. I took off the cover, and it seems that the woofer was drawn inwards and stays in that position. When I turn it off, the woofer returns to equilibrium. It goes back inwards and starts humming when I turn it on again. The left speaker still works perfectly though. I've had these speakers for 2 years and this problem suddenly started today. I've already tried just using the right speaker without audio input on several power outlets and the same humming occurs. Any ideas what's wrong?
It's not the speaker's fault. Your amp has the problem. If you switched the left and right speaker cables I bet the hum would switch to the left speaker. This sounds like DC is getting to your speaker which would indicate a bad amplifier channel. It could definitely cause harm to your speaker (blow the woofer), so I'd have the amp checked out and repaired before using it again. Do you have another amp you could substitute.

Also, recheck your connections and see that you haven't accidentally shorted the speaker connections...
These speakers are powered. There's an internal amplifier in the right speaker that powers it and the left speaker. The left speaker works fine when connected, but the right speaker still hums whether or not the left speaker is connected to it.
Regardless, the woofer sucking in like that indicates DC at the amp output, which can do harm to the speaker. It seems that only one channel of the amp is affected, which can happen. If you can unbolt the amp from the speaker and see if you can measure DC at the output terminals with it powered up, that would confirm that the amp is bad.

Perhaps you could send only the amp module back for service rather than sending the complete speaker... I would contact the company to see what they advise. Good luck.