I also own a P9 and a C2300. I have hardwood floors and a large KCS basshorn in my room. I had a rumble issue prior to installing a rega wall shelf. I previously had my P9 on a 3 inch maple slab with brass points on a Billy Bags stand. Now I do not have an issue thanks to the isolation of the shelf. I recommend that you attempt to isolate your table via a wall shelf prior to installing a rumble filter in the signal. Make sure that you mount it directly into the studs.
