Nick Zacharov

A real‐time binaural loudness meter

The alignment of sound intensity is of great importance, particularly in the field of psychometrics. When sounds have different spectral content, loudness alignment becomes a more suitable tool. However, traditional models assume the source either to reside in a free field at 0 azimuth or in a diffuse field. To assess or align sound‐source loudness at different locations or with different radiation characteristics is more problematic. This paper presents the development of a real‐time loudness meter based around the Moore loudness model. The tool has been developed in c and matlab and supports both diffuse and free‐field microphone input on a minimal hardware PC platform, with a generic sound card. Furthermore, binaural input to the model has been developed for a head and torso simulator (HATS). Use of a HATS allows for compensation of directional loudness properties caused by the head and pinna. It is thus possible to assess or align reproduction systems of different directivities or with different numbe...

Modeling and real-time auralization of electrodynamic loudspeaker non-linearities

The non-linear modeling of an electrodynamic speaker is studied and its use for real-time auralization of an arbitrary sound source is considered. First, the dominant observed non-linear behavior is presented. Then, a black-box approach to the system identification task is used seeking a generalized procedure applicable to any loudspeaker. In this respect, a separate identification scheme of the linear and non-linear characteristics of the loudspeaker is proposed. Some physical insight is used later in the model, which causes the loss of some of the desired generality. The model quality is finally assessed through subjective listening tests, and the results are presented.

Perceptual attributes for the comparison of head-related transfer functions

The benefit of using individual head-related transfer functions (HRTFs) in binaural audio is well documented with regards to improving localization precision. However, with the increased use of binaural audio in more complex scene renderings, cognitive studies, and virtual and augmented reality simulations, the perceptual impact of HRTF selection may go beyond simple localization. In this study, the authors develop a list of attributes which qualify the perceived differences between HRTFs, providing a qualitative understanding of the perceptual variance of non-individual binaural renderings. The list of attributes was designed using a Consensus Vocabulary Protocol elicitation method. Participants followed an Individual Vocabulary Protocol elicitation procedure, describing the perceived differences between binaural stimuli based on binauralized extracts of multichannel productions. This was followed by an automated lexical reduction and a series of consensus group meetings during which participants agreed on a list of relevant attributes. Finally, the proposed list of attributes was then evaluated through a listening test, leading to eight valid perceptual attributes for describing the perceptual dimensions affected by HRTF set variations.

An integrated printed circuit board (PCB) microphone

An electret microphone has been implemented into a printed circuit board. Due to novel construction the printed circuit board serves as the microphone backplate. Furthermore, other features of printed circuit board manufacturing technology are applied to minimize the number of components of the microphone. This results in a microphone that can be manufactured with the assembly of other electronic components during the manufacturing process. As a result a complete manufacturing process has been developed. To analyze the manufacturing process and the acoustical performance of the so-called PCB-microphone, the acoustics have been modeled, and backplate surface roughness, air gap thickness, electret charge, and overall sensitivity have been measured from prototypes.