title: Wind noise in hearing aids: II. Effect of microphone directivity.
abstract: OBJECTIVE
  The objectives were: (1) to examine the effects of a directional microphone with different directivity patterns and different microphone combinations on wind noise levels at the hearing aid output; and (2) to derive strategies appropriate for hearing aid selection and future designs.
  
  
  METHODS
  The in-situ frequency responses of a behind-the-ear hearing aid (BTE1) were matched when the hearing aid was programmed to dipole, hypercardioid, cardioids, or adaptive microphone mode. The in-situ frequency responses of another hearing aid (BTE2) were matched among an omnidirectional microphone (OMNI), an adaptive directional microphone (ADM), and a combination of an omnidirectional microphone at low frequencies and an adaptive directional microphone at high frequencies (MIXED). Flow noise was recorded at flow velocities of 0, 4.5, 9.0, and 13.5 m/s. Measurements were repeated for the hypercardioid pattern of BTE1.
  
  
  METHODS
  Flow noise recorded using directional microphones with four directivity patterns and using OMNI, ADM, and MIXED.
  
  
  RESULTS
  Directional microphones with different directivity patterns generated similar flow noise levels. ADM yielded higher overall levels than OMNI and MIXED, which had similar overall levels.
  
  
  CONCLUSIONS
  The adaptive directional microphone is the most versatile microphone for use in wind. The mixed microphone mode is a viable wind noise reduction option.
authors: Department of Allied Health and Communication Disorders, Northern Illinois University, DeKalb, Illinois 60115, USA. kchung@niu.edu
authors: King
authors: K
authors: Chung
mesh_terms: D000162:Acoustics; D000465:Algorithms; D000704:Analysis of Variance; D001307:Auditory Perception; D004867:Equipment Design; D006310:Hearing Aids; D006801:Humans; D008348:Manikins; D008422:Materials Testing; D009038:Motion; D009622:Noise / Q000009:adverse effects / Q000517:prevention & control*; D010470:Perceptual Masking; D012815:Signal Processing, Computer-Assisted; D013017:Sound Localization; D013018:Sound Spectrography; D014159:Transducers; D014919:Wind