ABSTRACT
One of the most common sources of noise in industry is the noise generated from vibrating machinery. For example, a 5-hP motor rotating at 1800 rpm is rather quiet, but if it is bolted directly to a metal table, the noise level can rise easily to 90 dBA at a distance of 5 ft. The metal tabletop acts as a sounding board and radiates the vibratory energy transmitted from some form of rotational unbalance of the motor. This sounding board effect is frequently found in industrial environments or buildings where floors or machine platforms are constructed of diamond deck, metal grills, hardwood, and even concrete. The excitation can originate not only from rotating equipment but from vibrators, tumblers, shakers, pressers, etc. It should be emphasized that noise is not the only undesirable effect. Floor vibration can be a serious problem to adjacent equipment, where close tolerances are maintained in machine tools or especially where optical devices are used.
