Evaluation of Audio Test Methods and Measurements for End-of-the-Line Automotive Loudspeaker Quality Control

In order to minimize costly warranty repairs, automotive manufacturers impose tight specifications and quality/reliability requirements on their part suppliers. At the same time, they also require low prices. This makes it important for automotive manufacturers to work with parts suppliers to define reasonable specifications and tolerances, and to understand both how the parts suppliers are testing and also how to carry out their own measurements for incoming QC purposes. Specifying and testing automotive loudspeakers can be very tricky since loudspeakers are inherently nonlinear, time-variant and effected by their working conditions and environment. This paper examines the loudspeaker characteristics that can be measured and discusses common pitfalls and how to avoid them on a loudspeaker production line. Several different audio test methods and measurements for end-of-the-line automotive speaker quality control are evaluated, and the most relevant ones identified. Speed, statistics, and full traceability are also discussed.