This is the Mitsubishi Dialtone D160, the largest subwoofer ever built, with 60 inches in the 1980s. 

Weighing 800kg, it can easily shatter windows and produces small earthquakes that can be felt like ground vibrations within a 2-kilometer range.

At the Koriyama factory, the test was conducted at first in the measuring room, but was stopped because the ceiling lamps fell due to vibration.

The outdoor test appeared to have a negative impact on the neighborhood. At a distance of about 100 m from the speaker, the sound was felt, but at a greater distance, it was transmitted as vibration and noise on the earth instead of an audible sound. 

Within a 2-kilometer radius of the factory, damage such as vibrations, small earthquakes, as well as noises from walls and windows occurred