Design characterization and testing of a custom air horn

Abstract

Construction and testing of an air horn can provide educational insight into how certain design decisions can influence resulting acoustic properties. Using readily available materials such as pvc pipe and tin sheeting, one can construct an air horn capable of producing sound waves in the 100+ decibel range and frequencies between 150 and 400 Hz. Upon completion of a prototype, many experimental opportunities are available. The degradation of sound intensity over a distance can be tested by use of a sound level meter. Due to the unidirectional behavior of the sound waves from the horn, samples from different distances and angles from the source can provide more understanding of how sound propagates as a wave in an open environment, as opposed to it being a simple directional wave. Upon completion of the testing, changes to the initial construction design can be implemented to investigate the relationship between the new model’s performance and the prototype’s. The air horn provides many opportunities for experimentation and testing. For example, frequencies and sound intensity can be altered by making design adjustments such as: diaphragm size, diaphragm material, housing material, bell size, nozzle length, etc. With a better understanding of the inner workings of these sound sources, one could use this design as a blueprint to expand the concept to either much larger or much lower frequency ranges which have applications in many different fields of study.