Originally Posted by clubman5
Done properly, a rubber band suspension pretty much eliminates low frequency rumble and 400hz howl. However, if your playing SO loud, you can hit the tonearms resonant frequency if the recording contains enough signal content around 400hz, then you will hear the arm howl.
Adding or subtracting mass from the tone arm will also solve this problem. You can lower the frequency by adding mass, raise it by removing mass. I also really like rumble notches in the frequency response of mixers. They seem to do a great job, but in the case of the PPD01, not having the notch makes the bass very flat.