The Evolution of Loudspeaker Measurement (or the futility of using 20th century tools to address 21st century needs) By Tim Gladwin Today’s hyper-competitive loudspeaker market puts product development teams under intense pressure to innovate and improve product performance while lowering development time and costs. And yet product developers are often saddled with mid-20th century tools that are expensive, slow and inaccurate. In this paper we will briefly review the history of loudspeaker measuring tools, their advantages and disadvantages, and compare them to a new measurement device from noted acoustic measurement pioneer Klippel GmbH. Klippel’s new Near Field Scanner (NFS) promises lower costs, fewer man-hours and greater accuracy than any other method. Anechoic chambers have been used to provide a controlled environment for loudspeaker measurement since the early 1930’s. They were developed to reduce the limitations of outdoor measurements: extraneous noise and weather. By 1946, Beranek and Sleeper had optimized wedge and chamber design (JASA 18-1 1946). Today’s anechoic chambers are essentially unchanged from Baranek & Sleeper’s time. At the time, the test signal was a slow swept sine wave from a heterodyne oscillator, often recorded directly to paper on a strip chart recorder. The ballistics of the pen and the…
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