Intensity vector measurements outside and inside cabs of earth moving machines

Inside cabs of earth-moving machines noise levels are often too high for the operator safety. Moreover, the strong competition on the European Economy Community Market makes urgent the need for rational noise improvement treatments. This paper describes a case study of noise control as applied to an articulated backhoe-loader already in production. The problem was the pressing need of lowering the noise level inside the operator cab by almost 2 dB. The use of the sound vector intensity technique allowed us to describe the complex acoustic field of the machine and to identify the various noise transmission paths from the primary sources to the receiver. Finally the proper use of soundproof materials allowed us to obtain the desired results in the most economical manner.