Modeling of acoustic environment for the purpose of noise cancellation

Abstract

The specific noise‐cancellation problem being considered here is the active cancellation of acoustic noise by the use of electronic earphones. Since it is important to achieve cancellation of ambient noise only, and not of warning sounds and speech, an adequate understanding of the noise environment in which the earphones are to be used is required. A key step in the approach taken by these authors is ton initially extract information regarding specific noise environments off‐line. This information can then be used to define details of control structure and values for the canceler in that environment. During actual usage of the earphones, the algorithm must adapt to fine‐tune itself to the environment at that time. Recordings of ambient noise were made for specific environments. Data‐analysis programs were developed and used to construct a model of the stationary noise environment and extract the relevant parameters. These are used to define the structure, parameter range, and computational requirements of the noise canceler. [Work supported by the Florida High Technology and Industry Council.]