Modeling and Measurement
of True Wireless Stereo (TWS) Wearables

July 20, 2021
9:00 AM Pacific (12:00 PM Eastern)

Overview

This Audio Product Education Institute webinar, expands on the topic of modeling, simulation and measurements in audio product development and the design process. Exploring the specifics of one of the newest and fastest-growing consumer electronics categories, combining the most cutting-edge technologies, the webinar intends to showcase how these processes fit in the design cycle.
 
Strong consumer demands have driven true wireless stereo (TWS) devices to become the most dominant category of product shipments in the past few years. The increased demand drove down selling prices, and with the market’s low barrier to entry, the mature supply chain resulted in better devices at lower price points, and vast shipments flooded the market in a short period of time. TWS earbuds are one of many wearable devices and are popular for pairing with smart watches, phones, and laptops. The voice sound quality of the many different products varies. This session will look at the subjective evaluation, acoustic measurement, and simulation of some typical TWS earbuds many of us use every day.
 
Session 1: Voice Sound Quality Assessment Over TWS Earbuds,
Roger Shively, JJR Acoustics
 
Presented and discussed will be the results of subjective evaluations of the voice quality received via a number of TWS earbuds. Audio examples of some devices in mostly live and mostly dead acoustic environments will be played and corresponding frequency response data will be shown. And, the description and results of listening tests for these devices will be shared.
 
Session 2: Testing the Audio Performance of Hearables,
Steve Temme, Listen, Inc.
 
Hearables are notoriously challenging to test. They have various interfaces ranging from hardwired to wireless (e.g. Bluetooth) and may contain much signal processing, both on the record side (e.g. beamforming, background noise filtering, voice activity detection, and on the playback side (e.g. loudness, compression, equalization, and active noise cancellation). This means that their characteristics change according to ‘real world’ conditions such as their physical environment and background noises. Some even have wake word detection, e.g. “Hey Siri”. Furthermore, their multifunctional nature means that there are many aspects of the device that may need to be tested, ranging from voice recognition to music playback or even operation as a telephone handset or hearing aid. Due to their complex non-linear use cases, these devices often need to be tested at different levels and in different environmental conditions, for example with background noise, different signals, etc. Presented will be some ways to acoustically measure these complex devices.
 
Session 3: Using Simulation in the Design of Hearable and In-Ear Audio Devices
Jinlan Huang, COMSOL
 
In this presentation, we will discuss how simulation can be used to help the design of hearable and in-ear audio devices such as hearing aids, earbuds, headphones, and headsets. We will look at examples that investigate the acoustics of an occluded human ear canal, study the effect of unwanted leaks or on-purpose open solutions in an earbud setup, or analyze the acoustics of a generic head and torso simulator to get the head-related transfer function (HRTF) and the mouth-to-ear transfer function. Other examples showcase how to model a miniature loudspeaker (a balanced armature receiver) using either a full detailed electro-vibroacoustic finite element analysis or a lumped representation, and how to study the interaction between the transducer and the rest of the system.
Steve F. Temme

President, Listen, Inc. Boston, Massachusetts, USA

Steve Temme is founder and President of Listen, Inc., manufacturer of the SoundCheck audio test system. Steve founded the company in 1995, and for the past 25 years the company has remained on the cutting edge of research into audio measurement, regularly introducing new measurement techniques, algorithms and hardware to enable testing of all kinds of devices ranging from basic transducers to complex audio systems. In recent years, Listen’s product development focus has been on creating the algorithms, interfaces and test methods to measure today’s many and varied wireless and cloud-communicating devices. Prior to founding Listen, Steve worked for many years as an acoustic test
and measurement applications engineer at Brüel & Kjaer, and also as a loudspeaker design engineer at Apogee Acoustics. He holds a BSME from Tufts University, has authored numerous papers on acoustic testing, and has lectured extensively throughout the world. 
Jinlan Huang

Lead Applications Engineer, COMSOL Massachusetts, USA

Jinlan Huang is a lead applications engineer for vibrations and acoustics at COMSOL and instructs acoustics training courses. She received her PhD from Boston University, Department of Aerospace and Mechanical Engineering, investigating acoustic wave propagation in complex-tissue environments and ultrasound-induced tissue heating and bleeding control. She joined COMSOL in 2011.
Roger Shively

Co-founder and Principal of JJR Acoustics Seattle, Washington, USA

Roger has over 35 years of experience in engineering research and development, with significant experience in product realization and in launching new products at OEM manufacturers around the world. Before co-founding JJR Acoustics in 2011, Roger worked as Chief Engineer of Acoustic Systems as well as functional manager for North American and Asian engineering product development teams in the Automotive Division of Harman International Industries Inc; a journey that began in 1986.
Roger received his degree in Acoustical Engineering from Purdue University in 1983, and finished post-graduate work in the field of finite element analysis. He is a member of the Audio Engineering Society, Acoustical Society of America, and Society of Automotive Engineering. He has published numerous research papers and articles in the areas of transducers, automotive audio, psychoacoustics, and computer modeling. Roger also holds US and International Patents related to the design of advanced acoustic systems and applications particularly in the field of automotive audio. Roger is Co-Chair of the AES Automotive Audio Technical Committee