AES Journal

Journal of the AES

2021 June - Volume 69 Number 6


Papers

Multiphysics Modeling of Audio Circuits With Nonlinear Transformers

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Transformers have been playing a fundamental role in the audio industry since the birth of audio electronics. The subtle flaws caused by the strongly nonlinear characteristic of their magnetic materials lead to enrichment of the signal harmonic content, thus contributing to that peculiar analog timbre well-liked by many musicians. In order to digitally emulate the unique shades of this analog gear, in this paper, a new methodology based on Wave Digital principles is presented. The method is highly flexible and able to accurately simulate the geometry/nonlinear behavior of magnetic cores while implementing the reference system physical domains (electric and magnetic) in a modular fashion. The nonlinear reluctances are modeled with Canonical Piecewise-Linear functions, which can be arbitrarily tuned to improve the accuracy of the representation. The algorithm presents itself as a hierarchical generalization of the so-called Scattering Iterative Method (SIM), i.e., a fixed-point method that has demonstrated outstanding performance for the simulation of large photovoltaic arrays and the emulation of audio circuits. The proposed multiphysics approach is thus characterized by some SIM features, such as the remarkable efficiency, and it paves the way toward the real-time multiphysics emulation of nonlinear audio circuits that is essential in Virtual Analog applications.

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Model-Based Adaptive Filtering of Dielectric Elastomer Loudspeakers

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Dielectric elastomers are soft actuators that can reach deformations by more than 500% when a high voltage is applied. They have been considered for use as loudspeakers because of their quick response. One of their limitations is an inhomogeneous frequency response, due to the modal behavior of the membrane. In this study, we set up a sensor-free adaptive filtering strategy that relies on a finite element model of the loudspeaker, to improve the frequency response.

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Cable Pathways Between Audio Components Can Affect Perceived Sound Quality

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The arena of highest fidelity in music reproduction, sometimes referred to as high-end audio, has many controversial claims and contentious issues. One such controversy is whether the cables and topology used to interlink components together make an audible difference. There seems to be a disparity between anecdotal experiences reported by audiophiles and published formal scientific research as to theminimal changes in system configuration that can be audibly distinguished. With the motivation of bridging this divide—which may originate from differences in instrumentation and subject-listening conditions used by the two groups—this work utilized a high-performance audio system and extended-duration listening protocol that more closely resembles audiophile auditioning conditions. With these measures the present work was able to prove through direct psychoacoustic testing that two different analog-interconnect pathways can be audibly distinguished.

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Design and Evaluation of a Scalable Real-Time Online Digital Audio Workstation Collaboration Framework

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Existing designs for collaborative online audio mixing and production, within a Digital Audio Workstation (DAW) context, require a balance between synchronous collaboration, scalability, and audio resolution. Synchronous multiparty collaboration models typically utilize compressed audio streams. Alternatively those that stream high-resolution audio do not scale to multiple collaborators or experience issues owing to network limitations. Asynchronous platforms allow collaboration using copies of DAW projects and high-resolution audio files. However they require participants to contribute in isolation and have their work auditioned using asynchronous communication, which is not ideal for collaboration. This paper presents an innovative online DAW collaboration framework for audio mixing that addresses these limitations. The framework allows collaborators to synchronously communicate while contributing to the control of a shared DAW project. Collaborators perform remote audio mixing with access to high-resolution audio and receive real-time updates of remote collaborators’ actions. Participants share project and audio files before a collaboration session; however the framework transmits control data of remote mixing actions during the session. Implementation and evaluation have demonstrated the scalability of up to 30 collaborators on residential Internet bandwidth. The framework delivers an authentic studiomixing experience where highresolution audio projects are democratically auditioned and synchronously mixed by remotely located collaborators.

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Standards and Information Documents

AES Standards Committee News

Page: 432

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Features

Listening Tests and Perception Research

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Papers and e-Briefs presented at the Fall 2020 Convention contained some interesting highlights in the domain of listening tests and perception research. Here we summarize six papers, two of which deal with software for running listening tests, three with the loudness of music and dialog, and the related impact of hearing impairment, and one on the masking effects of phantom sources.

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Departments

Book Reviews

Page: 439

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Obituaries

Page: 440

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Conv&Conf

Page: 442

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Extras

Table of Contents

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Cover & Sustaining Members List

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AES Officers, Committees, Offices & Journal Staff

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AES - Audio Engineering Society