Measuring Loudspeaker SPL Response and Harmonic Distortion at Low Frequencies

This article discusses how to measure loudspeaker SPL response and harmonic distortion at low frequencies in a standard environment, full of reflections from acoustically hard boundaries (e.g., walls, floor, and ceiling), room resonances, and even ambient noise reducing the dynamic range and accuracy of the measurements. The method combines near-field measurements with two identical microphones. This article was originally published in audioXpress, October 2023.

One of the biggest challenges with working from home during the pandemic was not having access to an anechoic chamber. This short tutorial, explains a simple solution for this: a “splice” measurement. The capability for such measurements has been included in SoundCheck since 2001. Despite its long history, this method has not seen widespread use. However, the current pandemic’s working challenges are sparking renewed interest. This article was originally published in Voice Coil, March 2021.

To help engineers and acousticians achieve accurate measurements in everyday tasks, Bruel & Kjaer has created a robust and reliable 1/2-inch CCLD pressure-field microphone - Type 4971-H-041. This new microphone was designed for measuring close to hard reflective surfaces, close to sound ports of audio devices or in flush mountings. The new Bruel microphone is also suitable for random-incidence measurements and free-field measurements with 90° incidence.

Designed for high-precision, free-field measurements and ideal where a microphone with high sensitivity is required, the new Brüel & Kjær Type 4966 family of measurement microphones is the latest expansion of the Danish company's toolset at the disposal of engineers and acousticians. With four different products adequate for accurate measurements and everyday tasks, the Type 4966 family offers a robust, and reliable range of free-field microphones for high-precision acoustic measurements.

Recently, there has been increased demand for loudspeaker 3-D directivity measurements both in the near- and far-fields for different applications. New holographic near-field scanning techniques provide new ways to determine the sound pressure at any point in the 3-D sound field. This article was originally published in Voice Coil, May 2015.