Have you tried the "sub crawl" ? You subwoofer may be located where the standing wave is giving the appearance of 1 ft above listening area. Simply relocating the sub to a better position may solve your problem. Also, have you used an SPL meter to set your levels?
Good Luck! and Take Care! Peace,
Forest Man
P.S.- Also, an upgrade to an SVS sub or subs may be in your future

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