AES New York 2019
Poster Session P3
P3 - Posters: Transducers
Wednesday, October 16, 10:30 am — 12:00 pm
P3-1 Acoustic Beamforming on Transverse Loudspeaker Array Constructed from Micro-Speakers Point Sources for Effectiveness Improvement in High-Frequency Range—Bartlomiej Chojnacki, AGH University of Science and Technology - Cracow, Poland; Mega-Acoustic - Kepno, Poland; Klara Juros, AGH University of Science and Technology - Cracow, Poland; Daniel Kaczor, AGH University of Science and Technology - Cracow, Poland; Tadeusz Kamisinski, AGH University of Science and Technology - Cracow, Poland
Variable directivity speaker arrays are very popular in many acoustic aspects, such as wearable systems, natural sources simulations or acoustic scanners. Standard systems constructed from traditional drivers, despite great DSP, have limited beamforming possibilities because of the very narrow directivity patterns for loudspeakers in high frequencies. This paper presents a new approach for micro-speakers array design from monopole sources, based on isobaric speaker configuration. New solutions allow to reach high efficiency in broadband frequency range keeping matrix size small. This presentation will contain an explanation of used isobaric speaker principles and comparisons between standard transverse transducers matrix and innovative point-source matrix in two configurations. Achieved results allow to improve beamforming effectiveness in a high frequency range with new driver matrix construction.
Convention Paper 10227
P3-2 Spherical Microphone Array Shape to Improve Beamforming Performance—Sakurako Yazawa, NTT - Tokyo, Japan; Hiroaki Itou, NTT - Tokyo, Japan; Ken'ichi Noguchi, NTT Service Evolution Laboratories - Yokosuka, Japan; Kazunori Kobayashi, NTT - Tokyo, Japan; Noboru Harada, NTT Communicatin Science Labs - Atsugi-shi, Kanagawa-ken, Japan
A 360-degree steerable super-directional beamforming are proposed. We designed a new acoustic baffle for spherical microphone array to achieve both small size and high performance. The shape of baffle is a sphere with parabola-like depressions; therefore, sound-collection performance can be enhanced using reflection and diffraction. We first evaluated its beamforming performance through simulation then fabricated a 3D prototype of an acoustic baffle microphone array with the proposed baffle shape and compared its performance to that of a conventional spherical 3D acoustic baffle. This prototype exhibited better beamforming performance. We built microphone array system that includes the proposed acoustic baffle and a 360-degree camera, our system can pick up match sound to an image in a specific direction in real-time or after recording. We have received high marks from users who experienced the system demo.
Convention Paper 10228
P3-3 Infinite Waveguide Termination by Series Solution in Finite Element Analysis—Patrick Macey, PACSYS Limited - Nottingham, UK
The acoustics of an audio system may comprise of several components, e.g., a compression driver producing plane waves, a transition connecting to the throat of a horn, and a cylindrical horn which is baffled at the mouth. While finite elements/boundary elements can model the entire system, it is advantageous from the design perspective to consider simplified systems. A compression driver might be used in many situations and should be designed radiating plane waves, without cross modes, into a semi-infinite tube. The pressure field in the tube can be represented by a series that is coupled to the finite element mesh by a DtN approach. The method is generalized to cater for ducts of arbitrary cross section and infinite cylindrical horns.
Convention Paper 10229
P3-4 Evaluating Listener Preference of Flat-Panel Loudspeakers—Stephen Roessner, University of Rochester - Rochester, NY, USA; Michael Heilemann, University of Rochester - Rochester, NY, USA; Mark F. Bocko, University of Rochester - Rochester, NY, USA
Three flat-panel loudspeakers and two conventional loudspeakers were evaluated in a blind listening test. Two of the flat-panel loudspeakers used in the test were prototypes employing both array-based excitation methods and constrained viscoelastic damping to eliminate modal resonant peaks in the mechanical response of the vibrating surface. The remaining flat-panel speaker was a commercially available unit. A set of 21 listeners reported average preference ratings of 7.00/10 and 6.81/10 for the conventional loudspeakers, 6.48/10 and 5.90/10 for the prototype flat-panel loudspeakers, and 2.24/10 for the commercial flat-panel speaker. The results are consistent with those given by a predictive model for listener preference rating, suggesting that designs aimed at smoothing the mechanical response of the panel lead to improved preference ratings.
Convention Paper 10230
P3-5 Modelling of a Chip Scale Package on the Acoustic Behavior of a MEMS Microphone—Yafei Nie, Institute of Acoustics, Chinese Academy of Sciences - Beijing, China; Jinqiu Sang, Chinese Academy of Sciences - Beijing, China; Chengshi Zheng, Institute of Acoustics, Chinese Academy of Sciences - Beijing, China; Xiaodong Li, Chinese Academy of Sciences - Beijing, China; Chinese Academy of Sciences - Shanghai, China
Micro-electro-mechanical system (MEMS) microphones have been widely used in the mobile devices in recent decades. The acoustic effects of a chip scale package on a MEMS microphone needs to be validated. Previously a lumped equivalent circuit model was adopted to analyze the acoustic frequency response of the package. However, such a theoretical model cannot predict performance at relatively high frequencies. In this paper a distributed parameter model was proposed to simulate the acoustic behavior of the MEMS microphone package. The model illustrates how the MEMS microphone acoustic transfer function is affected by the size of sound hole, the volumes of the front and back chamber. This model also can illustrate the mechanical response of the MEMS microphone. The proposed model provided a more reliable way towards an optimized MEMS package structure.
Convention Paper 10231
P3-6 Personalized and Self-Adapting Headphone Equalization Using Near Field Response—Adrian Celestinos, Samsung Research America - Valencia, CA, USA; Elisabeth McMullin, Samsung Research America - Valencia, CA USA; Ritesh Banka, Samsung Research America - Valencia, CA USA; Pascal Brunet, Samsung Research America - Valencia, CA USA; Audio Group - Digital Media Solutions
Variability in the acoustical coupling of headphones to human ears depends on a number of factors. Placement, size of user’s head and ears, the headband and ear-pad material are all major contributors to the sound quality delivered by the headphone to the user. By measuring the transfer function from the driver terminals to a miniature microphone set near the driver inside the cavity produced by the headphone and the ear, the degree of acoustical coupling and the fundamental frequency of the cavity volume was acquired. An individualized equalization on these measurements was applied to every user. Listeners rated the personalized EQ significantly higher than a generic target response and slightly higher than the bypassed headphone.
Convention Paper 10232
P3-7 Applying Sound Equalization to Vibrating Sound Transducers Mounted on Rigid Panels—Stefania Cecchi, Universitá Politecnica della Marche - Ancona, Italy; Alessandro Terenzi, Universita Politecnica delle Marche - Ancona, Italy; Francesco Piazza, Universitá Politecnica della Marche - Ancona (AN), Italy; Ferruccio Bettarelli, Leaff Engineering - Osimo, Italy
In recent years, loudspeaker manufacturers have proposed to the market vibrating sound transducers (also called shakers or exciters) that can be installed on a surface or a panel to be transformed in invisible speakers capable of delivering sound. These systems show different frequency behaviors mainly depending on the type and size of the surface. Therefore, an audio equalization is crucial to enhance the sound reproduction performance achieving flat frequency responses. In this paper a multi-point equalization procedure is applied to several surfaces equipped with vibrating transducers, showing its positive effect from objective and subjective point of view.
Convention Paper 10233