Entries by Zarina

Loose Particle Detection

During the loudspeaker manufacturing process, particles may become trapped inside the loudspeaker, resulting in a distinctive defect that is easily heard but difficult to measure. To give a clearer view of the problem, Time-Frequency maps are shown for some defective loudspeakers. Based on this analysis, a reliable testing procedure using a swept-sine stimulus, high-pass filter, […]

Virtual Instruments for Audio Testing

Although Virtual Instruments have been part of SoundCheck as long as most of us can remember, back in 1998 this was a huge innovation. This paper introduces the concept at a time when computerized audio measurement was a novel concept. Authors: Steve Temme Presented at the 105th AES Convention, San Francisco, 1998 Full Paper

HarmonicTrak Algorithm for Fast and Accurate Swept Sine Measurement

Author: Steve Temme The sine generator in SoundCheck®, operates on the same principles as a traditional swept sine measurement system consisting of a sine generator, voltmeter, tracking filter, and level recorder. The main difference is that it is implemented in the software as a virtual instrument. The SoundCheck sine generator sweeps in discrete steps; each […]

Are You Shipping Defective Loudspeakers to your Customers?

Author: Steve Temme Loudspeaker distortion is undesirable. The type and level of distortion, however, can greatly influence the perceived annoyance. In addition, identifying the type of distortion can also help pinpoint the mechanism or mechanisms in the loudspeaker that are causing the distortion. “Rub & Buzz” is a good example of a particularly annoying type […]

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Evaluation of Loudspeaker Performance at Low Frequencies

Authors: Steve Temme and Christopher J Struck Evaluation of loudspeaker performance at low frequencies is complicated by long wavelengths, room interaction and cabinet/baffle diffraction. Since low frequency measurements have traditionally required large, impractical testing environments, different techniques have been developed in an attempt to overcome this requirement. Anechoic chambers, outdoor measurements, half-space measurements, ground plane […]

Audio Distortion Measurements

Author: Steve Temme In the never ending quest for better sound transmission, reinforcement, and reproduction, the electronics have been extensively analyzed for distortion. Distortion in the electroacoustic transducers, while typically several orders of magnitude greater, has often been neglected or not even specified because it has been difficult to measure and interpret. With a basic […]

Time Selective Measurements with a Logarithmically Swept Sine

Author: Martin Rung A time selective measurement of a frequency response is (directly or indirectly) based on a measurement of the impulse response, where a well-defined time window is applied to the impulse response. The frequency response is simply the Fourier transform of the impulse response. Time selective measurements are often used in electroacoustics to […]

How to Graph Distortion Measurements

Distortion curves are conventionally plotted under the corresponding excitation frequency of the measured fundamental. Interpretation of results can be misleading due to the influence that the passband shape and amplitude irregularities of the fundamental response have on the distortion responses. By ‘amplitude normalizing’ the distortion responses to the measured fundamental response before plotting them at […]