This should not be surprising; smashing a wave into the floor is never optimum.
Elevating subwoofer about two feet off the floor
Acoustic Sciences Corp recommends elevating the subwoofer about 2' off the floor http://www.acousticsciences.com/products/subtrap
see photo in link above ... has anyone tried raising their subs that high off the floor? Did it sound better?
see photo in link above ... has anyone tried raising their subs that high off the floor? Did it sound better?