We have seen this problem hundreds of times over the decades. The problem is NOT in your speakers. We believe as many others here it is compliance problem. The simple solution is to use a rumble filter, if you really want to find out what the problem is here is what we suggest. Take just your turntable to a completely different system and play it with several different albums, if it still has a rumble problem then the problem is in your turntable, if not it could be your phono pre or interconnects. If the problem exists in your turntable, first check your tonearm for problems like loose bearing or places where it maybe hanging up along it's arch also check your setup parameters on your cartridge to make sure they are correct ( We always suggest using a test LP on any setup) If the problem persists change the cartridge to one that is more compliant to your tonearm (check your setup again) If the problem still exists then it would have to be in your tonearm. Many times we had to change the tonearm to eliminate the problem, as strange as it may seem there are times when we changed the tonearm with the exact same model tonearm and it solved the problem, we refer to those pieces of equipment as having "spooks" in them, we ship all those pieces to the X Files. Good turntable isolation cannot be understated and definitely improves the quality of vinyl playback but we have placed turntables on solid concrete platforms and they still had rumble problems, how can that be? Don't know but it happened. More X files stuff.