A Method for Characterizing the Noise Produced by an Agricultural Tractor in Terms of the Acoustic Power and Directivity

Abstract

In agriculture, as in the civic, military and industrial areas, excessive noise is a problem that must be recognized. Tentative criteria have been established that specify the maximum noise levels that people can be exposed to for various time periods without receiving permanent hearing damage. In many cases, the noise produced at the operator’s location by agricultural machines is considerably above the maximum safe level for continuous daily exposure. The seriousness of the problem is further emphasized when it is realized that many young men in their teens are operating agricultural machines. The hearing damage that they receive will be with them for the rest of their lives. In attempting to solve a noise control problem, it is often helpful to consider the problem in the framework of a three part system. The three components of the system are the source, the path, and the receiver. In this investigation, an attempt was made to characterize the noise produced by an agricultural tractor (the source). In characterizing the source, the air (a path) was also used. No attempt was made to evaluate the effect of the noise on the operator (receiver), alter the path that the noise took in reaching the operator, or decrease the noise produced by the tractor. A straightforward, versatile, reliable method for characterizing the noise produced by a tractor will be valuable in solving the problem of excessive noise associated with agricultural machines