Well that's 1 of many reasons why I gave up on vinyl. Does it happen on all albums? It could it be an off center hole or warp if the thump is only 1 time per revolution. I know I'm not much help but that was a severe problem I encountered all too much back in the day when I had a vinyl rig.
subwoofer thump on player
albums are all stored vertically
with the sub I get the once a rotation light subwoofer thump
at low volume levels
will a record clamp or weight help
still a cd guy mostly
with the sub I get the once a rotation light subwoofer thump
at low volume levels
will a record clamp or weight help
still a cd guy mostly