Brüel & Kjær Brüel & Kjær is a world-leading manufacturer and supplier of products and systems relating to sound and vibration measurement and analysis. Its customers are as diverse as its products and come from a wide range of industries that include automotive, aerospace, consumer goods and telecommunications, as well as national government agencies. Brüel & Kjær helps them solve a long list of sound and vibration problems - ranging from environmental noise measurements and building acoustics to structural dynamics, vibration measurements, and quality control. Today, Brüel & Kjær has 900 employees and sales offices in 55 countries. Brüel & Kjær is a subsidiary of UK-based Spectris plc.