Objective analysis of ambisonics for hearing aid applications: Effect of listener's head, room reverberation, and directional microphones

J Acoust Soc Am. 2015 Jun;137(6):3447-65. doi: 10.1121/1.4919330.

Abstract

Recently, an increased interest has been demonstrated in evaluating hearing aids (HAs) inside controlled, but at the same time, realistic sound environments. A promising candidate that employs loudspeakers for realizing such sound environments is the listener-centered method of higher-order ambisonics (HOA). Although the accuracy of HOA has been widely studied, it remains unclear to what extent the results can be generalized when (1) a listener wearing HAs that may feature multi-microphone directional algorithms is considered inside the reconstructed sound field and (2) reverberant scenes are recorded and reconstructed. For the purpose of objectively validating HOA for listening tests involving HAs, a framework was developed to simulate the entire path of sounds presented in a modeled room, recorded by a HOA microphone array, decoded to a loudspeaker array, and finally received at the ears and HA microphones of a dummy listener fitted with HAs. Reproduction errors at the ear signals and at the output of a cardioid HA microphone were analyzed for different anechoic and reverberant scenes. It was found that the diffuse reverberation reduces the considered time-averaged HOA reconstruction errors which, depending on the considered application, suggests that reverberation can increase the usable frequency range of a HOA system.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Acoustics / instrumentation*
  • Algorithms
  • Amplifiers, Electronic*
  • Auditory Perception*
  • Computer Simulation
  • Equipment Design
  • Facility Design and Construction*
  • Fourier Analysis
  • Head / anatomy & histology*
  • Hearing Aids*
  • Humans
  • Models, Theoretical
  • Motion
  • Reproducibility of Results
  • Sound*
  • Time Factors
  • Transducers*
  • Vibration