You may also have a feedback issue. Turntables can be very sensitive to this and need to be well isolated. Kind of like having a microphone too close to the speakers on a PA system. However, with turntables, instead of a squeal, the feedback is in the bass region.
Some have found that placing the turntable on a shelf extended from the wall provides a better platform than having the turntable sit on a cabinet or shelf assembly that sits on the floor.
Some have found that placing the turntable on a shelf extended from the wall provides a better platform than having the turntable sit on a cabinet or shelf assembly that sits on the floor.