Turntable feedback rumble problems with new sub

HI,
Try to get a decent rack, adding platforms, granites, marbles and all kinds of that stuff will not have the desired outcome sonically,  for they store some energy, and still the current support will be in question and most propably you will upset orher parts of sonic spectrum. You can then experiment with any kind of footing devices if you want.

Yes, as slaw and others have said, it’s a turntable problem. One that needs addressing asap before you wreck the voice coil/spider assembly through heat.

Some amps have built-in filters to cut subsonic signals from reaching the speakers but most don’t.

Don’t ignore it. My friend had a similar issue with his Pro-Ject Carbon which resulted in a burnt out sub on of his Kef's.

Check everything turntable related. From cartridge tip, to arm, to turntable placement.

As a reward you’ll get better sound too.

Please report back once you've tried at least 5 things and while
using the sub you still have issues.

Son in law had a similar problem at loud volumes with Def Tech SM55 monitors sitting on the same cabinet as turntable.  We put Vibrapads under the speakers—helped a lot. Upgraded to IsoAcoustic Isopucks, helped even more. I have Isopucks under the speakers in my second system as well—made a huge improvement. Gaia IIIs under speakers in my main system. Big fan of IsoAcoustic. 

I just tried moving my speakers from the console to the floor. Made a huge difference. I’m going to order stands for the speakers and do some additional isolation under the turntable and under the furniture feet and see if that eliminates it completely.  Stands are a tight fit in the room but necessary even if I tried to change the furniture. Thanks for the input all.