In this application note we provide an overview of the key electroacoustic measurements used to characterize the performance of loudspeaker drive units and loudspeaker systems. We focus on the most important objective measurements and refer to industry standards for guidance.
Compared to electronic audio test, measuring loudspeakers is complicated. First, to measure sound levels accurately requires precision measurement microphones and supporting electronics, which have a known, stable sensitivity and flat frequency response over the frequency range of interest. Measurements are further complicated by the interaction of the loudspeaker under test with the test environment. Ideally, we want to measure the direct sound radiated from the DUT without any contamination caused by reflections from walls, floors, or ceilings, etc. Special rooms called anechoic chambers are available for this purpose, but they are very expensive. And even the best ones are usually not fully anechoic at the lowest frequencies of interest.