The vibrational and acoustical behavior of components is of major concern to many design engineers. Unchecked vibration can lead to misalignment, accelerated part wear and noise. The automotive industry is especially concerned about noise and vibration levels associated with engines, compartments, brake systems, pulley systems, etc. A good design coupled with the best fabrication material should help to ensure a quieter and more vibrationally stable system. This study evaluates the vibrational and acoustical properties of thermoset composites, steel and aluminum.