Discovered one more effective resonance reducing method for the RM or RPM 6 series turntable. As you know the plinth transmits vibration to the tonearm from the motor. The tonearm assembly is connected to a recessed section of the the plinth with only three screws. You can remove the screws and install a square piece of rubber that fits into the recessed area, or use the grommets to isolate the tonearm plinth. The rubber square I used was 2 1/2 x 2 1/2 by 1/8 thick. Be careful holding the tonearm at the removal of the last screw as the cartridge will be exposed.
You will need to adjust the VTF and the tonearm lift the same height as the thickness of the rubber square. Easy to do with two smaller allen wrenches. Installing the rubber square was less than 10 minutes and getting the VTF and tonearm hold adjusted was another 10 minutes. In my system, it continued to significantly improve all the elements of the soundstage already mentioned.
You will need to adjust the VTF and the tonearm lift the same height as the thickness of the rubber square. Easy to do with two smaller allen wrenches. Installing the rubber square was less than 10 minutes and getting the VTF and tonearm hold adjusted was another 10 minutes. In my system, it continued to significantly improve all the elements of the soundstage already mentioned.