I haven't read all of the responses to your question. Forgive me if I'm totally off base.
While you are rethinking your underlying problem consider whether or not you might have a mis-match between the mass of your TT's arm and the stylus' compliance. That can cause minor or major subsonic problems. Some times these are severe enuf not to be curable by just using a subsonic filter. Some more anal folks would find this type of fix undesirable in any event. They would want to fix the underlying problem, not just use a band aid. If you've already eliminated this possibility march onward............:-)
While you are rethinking your underlying problem consider whether or not you might have a mis-match between the mass of your TT's arm and the stylus' compliance. That can cause minor or major subsonic problems. Some times these are severe enuf not to be curable by just using a subsonic filter. Some more anal folks would find this type of fix undesirable in any event. They would want to fix the underlying problem, not just use a band aid. If you've already eliminated this possibility march onward............:-)