Why do my bass drivers shake violently listening to vinyl

@williewonka how can I tell if the bearings have any play in them? Not sure what you're referring to.

@artemus_5 I noticed this any time any record is playing. It is not genre specific. And like I said, there is no discernible audio issue. Just the bass drivers going in and out like mad. 

You need a rumble filter, a low frequency filter specifically created to solve these problems with vinyl playback.

What's going on is that you are getting a strong signal below the resonance filter of the port, so there's no longer an air spring there to hold the driver back.

If you can conveniently plug the port you should try and watch again. :)

Still, you need a rumble filter to reduce the strain on your amp and speaker, and yes it's dangerous, either from excess excursion or overheating of the coils.

Of course, you may also need better isolation of your turntable. On a springy wooden floor a simple stand will not be good enough.

What arm and cartridge are you using!  Put the information in this calculator and you will get the resonance frequency number!
http://www.mh-audio.nl/Calculators/RF.html

@erik_squires Excellent post!! 

I suspected it was dangerous. The excursion or cone travel is pretty extreme and it seems to be as you said with no spring holding back the driver. 

And, yes, I have a springy wooden floor in a second floor bedroom and a cheap Pangea audio rack.

I could try plugging the port although with the Treo's they are located on the bottom. I will absolutely look into getting a rumble filter.

Thanks all!!