On the selection of the number of beamformers in beamforming-based binaural reproduction

Itay Ifergan, Boaz Rafaely

Research output: Contribution to journalArticlepeer-review


In recent years, spatial audio reproduction has been widely researched with many studies focusing on headphone-based spatial reproduction. A popular format for spatial audio is higher order Ambisonics (HOA), where a spherical microphone array is typically used to obtain the HOA signals. When a spherical array is not available, beamforming-based binaural reproduction (BFBR) can be used, where signals are captured with arrays of a general configuration. While shown to be useful, no comprehensive studies of BFBR have been presented and so its limitations and other design aspects are not well understood. This paper takes an initial step towards developing a theory for BFBR and develops guidelines for selecting the number of beamformers. In particular, the average directivity factor of the microphone array is proposed as a measure for supporting this selection. The effect of head-related transfer function (HRTF) order truncation that occurs when using too many beamformer directions is presented and studied. In addition, the relation between HOA-based binaural reproduction and BFBR is discussed through analysis based on a spherical array. A simulation study is then presented, based on both a spherical and a planar array, demonstrating the proposed guidelines. A listening test verifies the perceptual attributes of the methods presented in this study. These results can be used for more informed beamformer design for BFBR.

Original languageAmerican English
Article number6
JournalEurasip Journal on Audio, Speech, and Music Processing
Issue number1
StatePublished - 1 Dec 2022


  • Beamforming
  • Binaural reproduction
  • Directivity factor
  • Higher order Ambisonics
  • Microphone arrays

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • Acoustics and Ultrasonics


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