Selecting Sound Source Localization Techniques for Industrial Applications

Sound source localization is a complex and cumbersome task that most acoustics engineers face on a daily basis. Today, a number of rather standard methods help accelerate this task. But there is no one-size-fits-all solution. This article describes the most common techniques and reviews vital criteria to select the best method for the job at hand. The toughest challenge facing any acoustics engineer is figuring out where the sound originates – especially when there is considerable interference and reverberation flying around. Since the early 1990s, some rather standard and highly functional methods based on microphone arrays have matured, and today they are used throughout many industries. In general, the methods fall into three categories: near-field acoustic holography, beamforming, and inverse methods. Even though these basic techniques have undergone constant improvement, the problem remains that there is no “magical” sound source localization technique that prevails over the others. Depending on the test object, the nature of the sound and the actual environment, engineers have to select one method or the other. This article reviews available techniques and explains how the methods have evolved over the years. Readers will be able to understand how to assess the quality of the measurement result based on two criteria – spatial resolution and dynamic range – as well as reviewing criteria to determine which method results in the best sound source localization for the job. The various methods discussed will be frequency range, distance to the source, physical properties of the sound source, and operational conditions. A number of examples are presented regarding the different techniques.