Headphones, Headsets & Earphones: Electroacoustic Design & Verification

Presenter:
Christopher Struck, CJS Labs - San Francisco, CA, USA; Acoustical Society of America

This tutorial reviews basic the electroacoustic concepts of gain, sensitivity, sound field correction, linear and non-linear response, and test signals for ear-worn devices. The insertion gain concept is explained and free and diffuse field target responses are shown. Equivalent volume and acoustic impedance are defined. Ear simulators and test manikins appropriate for circum-aural, supra-aural, intra-aural and insert earphones are presented. The salient portions of the ANSI/ASA S3.7 and IEC 60268-4 standards are reviewed. Examples of frequency response, insertion gain, left-right tracking, distortion, and impedance are shown. Issues with interfacing to digital devices over USB or Bluetooth are discussed. Evaluation of active and passive noise canceling devices is also presented.