Why do my bass drivers shake violently listening to vinyl

@erik_squires

I have no real knowledge of electronics as you do. But I have been involved in using stereo systems for 60 yrs and can only speak from my observations. That said, I have seen my subwoofers pump wildly...or at least what I thought was wildly. It was much more than 10 mm. But I have never had any sound issues nor break downs. That said, Why does it still sound " incredible " according to the OP? I know what sub sonic means but I have heard it before in a system..at least thats what I thought it was. It DID go away with the subsonic filter
BTW I'm seeking answers not a fight (-:

The flopping is due to things you can't hear, and the OP should be grateful that he didn't have the volume up any higher. :)

Those signals could be in the 5-10Hz range, quite easily.  Removing them wont' make it sound less incredible. :)

I generally prefer to go from the simple to the complex, in trying to solve any problem.  Simple is to either move your turntable in your listening room or suspend it, or both.  Complex is to add a subsonic filter.  If you add a subsonic filter, then a steep slope at a frequency below 20Hz is desireable, but 24db/octave is to be preferred over 18db/octave, because of phase anomalies that may affect upper frequencies. (6db/octave is also good but much too gradual for slope in this case. 12db/octave and 18db/octave are less "good" compared to 24db/octave.)  I will bet that moving the TT will solve your problem or at least ameliorate it sufficiently so as not to be a bother.

+1 erik, problem most likely subsonic 5Hz or so. Use a 24dB/octave filter, the steeper the slope the better.

@lewm

I generally prefer to go from the simple to the complex, in trying to solve any problem. Simple is to either move your turntable in your listening room or suspend it, or both. Complex is to add a subsonic filter

I agree wholeheartedly with this approach