A mic diaphragm is designed to move only when the air around it vibrates; this is usually the case when keeping the mic in a fixed position. However, imagine the mic housing being shaken. The diaphragm is relatively reluctant to move due to mass, air resistance and mechanical compliance; so, the housing moving more than the diaphragm also generates an output. A: Diaphragm vibrates due to acoustic sound. B: Housing vibrates due to transferred mechanical excitations. Both cases create an output si