Your speakers should definately NOT be in the same cabinet as your turntable. Also check your stylus pressure with a suitable gauge, and make sure that the cantilever/stylus assembly is not visually damaged using a magnifying glass.
B+O turntable problem
I have a B+O TX2 turntable with an MMC5 cartridge, which sounds horrible. The sound is rumbly and distorted in both the right and left channels. I am assuming I need a new cartridge, but I am not sure if that is actually the problem. I can get an MMC4 cartridge from Soundsmith, but wonder if I should or can do anything to make sure the cartidge is bad before I replace it.