It'a an un-suspended table, so the vibrations created when tapping on the base will be directly transmitted to the arm and platter. If that's your only issue, you're home free! Just stop tapping on the plinth....
However, if you have other resonance issues, try putting the table away from the speakers. If it comes down to it, trying your bitumen sheets might help, but there are a variety of sound absorbers (Sorbathane, etc) on the market that would likely do a better job. But, hey, experiment a little!
Regards
Jim
However, if you have other resonance issues, try putting the table away from the speakers. If it comes down to it, trying your bitumen sheets might help, but there are a variety of sound absorbers (Sorbathane, etc) on the market that would likely do a better job. But, hey, experiment a little!
Regards
Jim