My encounter with low frequency noise was just a high speed lift audible from the flat, but it made me realize I strictly want to avoid this in future. The lowe

My encounter with low frequency noise was just a high speed lift audible from the flat, but it made me realize I strictly want to avoid this in future. The lower you go, the more unsuppressable[0] the sound gets, and at some point you start feeling more than hearing it. [0] You need material as thick as the wave is long, although allegedly there have been papers investigating the use of metamaterials that are much thinner—presumably for military use by subs—there is nothing commercially available yet.