One of my L22s makes a mechanical "clicking" sound when certain subsonic signals appear to be present. I've noticed it on movies that apparently have sudden signals at or that begin below the audible thresh hold. The cones move, but no sound other than the clicking. The other L22 doesn't make this noise on the same passages. I've not experienced this playing music, just with movies. Thoughts?
Display: Vizio P55-E1l Pre-pro: Marantz 7703; Amps: Emotiva XPA-2 Gen 2, Emotiva XPA-3 Gen 1, H/K AVR 520 (direct in to amps); Sources: Sony UBP-X700; X-box 1 S; Technics 1200 Mk II; Win10 PC for digital; Phono Preamp: Emotiva XPS-1; Speakers - LR: Philharmonic BMR LR; Center: Selah Audio BMR-CC; Surrounds: Wharfedale Reva-2; Rear Surrounds: Wharfedale Diamond 220; Atmos: TF - Monoprice Alpha 8; TR - BIC VI-38; Subwoofers: dual Rythmik L22s