Knowles Corp. supplies advanced micro-acoustic, audio processing and precision device solutions. It operates through the following segments: Audio and Precision Devices. The Audio segment includes analog and digital micro-electro-mechanical systems microphones, electret condenser microphones, smart microphones, ultrasonic sensors, acoustic processors and balanced armature speakers. The Precision Devices segment offers ceramic capacitors, electromagnetic interference filters, capacitors, single layer capacitors, precision variable capacitors, and thin film devices across diverse end markets, such as industrial, defense, aerospace, medical, and telecommunications markets. The company was founded by Hugh Knowles in 1946 and is headquartered in Itasca, IL.