TAPC Virtual Conference Program

VIRTUAL CONFERENCE

HBK Electroacoustics

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Conference Agenda 28 September 2021

Keynote Presentation

8:30-9:00 AM PST
Erik Ziegler, TAPC Business Development Manager, Hottinger Brüel & Kjær

Over the last couple of years we have all been facing new challenges giving rise to some new global trends in the market for Audio products. In this keynote presentation we will address some of these new trends, how they relate to audio products as well as how they affect the both the market and what can be done to ensure continued development and supply.

Track 1: DSP, Physics and Human Perception

9:00-10:00 AM PST

For those new to the field of electroacoustic measurements, this short tutorial provides an overview of the quantities that are basic to describing the performance of an electroacoustic system, whether headphones, speakers, microphones, mobile phones or whatever the future brings. The language of electroacoustics, including the many flavors of the decibel, the many ways to measure frequency response and which distortion measurements provide an undistorted picture of a products performance are just some of the concepts discussed.

Speaker
The presenter’s interest in audio and acoustics started with his tenure in a garage band in the 1960s, where he experienced live performances, studio recording sessions and even a TV appearance at the New York World’s Fair of 1965. He caught the technology bug and with his degrees in mechanical engineering from Cooper Union and MIT, entered the field of acoustical consulting. Joining Bruel & Kjaer in 1982, Marty spent the next 35 years as a Senior Sales Engineer and Telecom Audio Market Manager for the company. Now semi-retired, he still maintains his association with HBK and works with the Telecom Audio PC group and occasionally lectures. He lives in New Jersey with his wife of almost 50 years, their dog Chance, and his 2006 Red MX-5 Miata.

10:00-11:00 AM PST

This course will describe Noise Source Identification (NSI) techniques that can turn weeks into minutes. Since NSI tools are continually advancing, this course will expose students to the latest array techniques with enough theory to gain a basic understanding of what is required without being overwhelmed. This course will describe Nearfield Acoustic Holography, Planar and Spherical Beamforming and the many options associated with each through theory and a variety of case studies highlighting practical application of each technique.

Speaker:
Tony Frazer, Hottinger Brüel & Kjær. Education: BSME – Michigan Tech Univ – MSME – Wayne State Univ – Experience: General Dynamics Electric Boat, Detroit Diesel Corp, Bruel & Kjaer / HBK

11:00 AM-12:00 PM PST

Fabrics are used for speaker grates and to cover cell phone microphones and speakers. It is important that these fabrics produce minimal acoustic distortion while fulfilling their functional requirements – aesthetics and waterproofing. The B&K 4206T impedance tube is used to minimize the sound transmission loss and to guide the design, but the measurement is tricky. Proper test technique will be shown including source spectrum shaping, sample mounting, and testing small samples.

Speaker

Ed Green has been a noise engineer in the Detroit area for the last 26 years. Ed holds a Ph.D. from Purdue University. Ed’s PhD thesis focused on “smart” foams for Active Noise Control, and his Masters thesis was on the subject of foam modeling.

1:00-2:00 PM PST

Simple frequency response measurements were made on a range of sound reproduction systems including:

1. Compact Disc

2. Streaming Audio (MP3)

3. A vinyl record player

The measurements were then compared to a simple “blind listening test” involving a small group of listeners. Based on frequency response alone, it is clear that the measurements do not correlate to listener preference.

Speaker

Mark Serridge is a graduate of ISVR (Institute of Sound & Vibration Research) at Southampton University, England. He graduated in 1983 with a BSc (Honors) degree in Engineering Acoustics and Vibration. He spent two years as an R&D engineer in loudspeaker development at Electroacoustic Industries Ltd  (ELAC) in London. He then joined B&K at its HQ in Naerum, Denmark where he began as a Technical Author before moving into an Application Engineer role, and then into sales and marketing. He has spent the last 20 years in sales in California. He is based in Los Angeles.

Track 2: Simulation, DIY ElectroAcoustic Programming and Test Services

9:00-10:00 AM PST

In this presentation we will look at the physics involved when modeling ear and ear canal simulators. This includes the acoustic thermal and viscous boundary layer losses that define the damping properties of narrow regions. We will investigate how to set up and model a BK Type 4157 ear simulator (the so-called 711 coupler) using COMSOL Multiphysics. Finally, we will look at ways to use the results in a virtual test setup. This includes a full 3D simulation as well as how to identify, compute, and use lumped representations.

Speaker:
Mads Herring Jensen joined COMSOL in 2011 and is the technology manager for the acoustics products. Mads has a PhD in computational fluid dynamics from the Technical University of Denmark. Before joining COMSOL, he worked in the hearing aid industry for five years as an acoustic finite element expert.

10:00-11:00 AM PST

Vince will demonstrate a new HBK software dedicated to electro-acoustic testing called: Electro-Acoustic Engine (EA-engine). This software is a complete tool box that has “calibrated” DSP for charaterizing electro-acoustic transducers such as speakers and microphones. It is designed to work with the famous HBK 3670 8in/2out audio interface. Vince will use the Visual Studio (VB) programming language and show how to use the simple EA-engine API to get frequency responses and distortion estimates.

Speaker:
Vince Rey graduated from the Institut Universitaire de Technolgies d’Orsay (Paris XI) and Saint-Etienne in France with a bachelor degree of science in computer information systems specialized in instrumentations. He moved to the US in 2001 and worked for various companies as a NVH (noise, vibration and harsness) application and sales engineer. He joined Hottinger, Bruel & Kjaer in 2013 as key account manager focusing on electro-acoustic applications. Vince has a deep passion for delopping applications that relate to audio and music.

11:00 AM-12:00 PM PST

HBK has developed a dedicated toolbox on top of the 3670 DAQ with the essential functionalities needed for electroacoustic testing. Stéphane will explain the architecture of this toolbox, covering the different ways to use it with the 3670 DAQ and illustrate its use through some demonstrations based on MALTAB and Python programming.

Speaker:
Supméca (Institut supérieur de mécanique de Paris) engineer, Stéphane Giclais joined HBK – Hottinger Brüel & Kjær in 2016 as services and solutions engineer on acoustic and vibration applications for aerospace, automotive and telecom-audio industries. Prior to joining HBK, Stéphane worked as a project leader in aircraft GVT for ONERA for 6 years. Before, he has worked for several companies as a noise and vibration engineer including Brüel & Kjaer, MTS Systems and SRDC.

1:00-2:00 PM PST

During this presentation, we will introduce recent projects performed by the Engineering Services team at HBK to support automotive customers with Voice Recognition and Audio System Sound Quality.
We will start with a description of the challenges faced by HBK customers followed by the methodology developed to address them.
We will then share an overview of the results obtained as well as the direction for future work.

Speaker:
Rabah Hadjit holds a Ph.D. from the University of Mons in Belgium. He developed more than 20 years of experience in Noise and Vibrations while working for CAE solution providers, an automotive supplier, and a wind turbine manufacturer. Rabah currently works as a Principal Consultant for Hottinger Brüel Kjær Engineering Services.
Rabah focuses on further developing Hottinger Brüel and Kjær engineering services offering to provide HBK customers with a complete test and CAE solution in collaboration with a variety of CAE partners.

2:00-3:00 PM PST

This presentation will cover the basics of the LAN-XI Open Application Programming Interface including hardware compatibility, REST commands, and the steps required to build a simple recorder app.

Speaker:
Matt Houtteman is a graduate of Purdue University School of Mechanical Engineering (BSME 2007, MSME 2011)

3:00-4:00 PM PST

Bruel & Kjaer sound level meters have long been a leader in reliable, portable, precision sound measurement. With the addition of an Open API, modern B&K 2245, 2250 and 2270 sound level data can be measured and send directly to your custom applications for R&D, Production Test, etc. In this presentation, we will introduce the capabilities of the Open API and review examples of how they can be integrated into non-proprietary test platforms.

Speaker:
Bruel & Kjaer sound level meters have long been a leader in reliable, portable, precision sound measurement. With the addition of an Open API, modern B&K 2245, 2250 and 2270 sound level data can be measured and send directly to your custom applications for R&D, Production Test, etc. In this presentation, we will introduce the capabilities of the Open API and review examples of how they can be integrated into non-proprietary test platforms.

Conference Agenda 29 September 2021

Track 3: Electroacoustic Applications

9:00-10:00 AM PST

There are many, well-established approaches to measuring and evaluating distortion that impact audio quality in products. THD and rub & buzz metrics are used for evaluating harmonic distortion and the PEAQ algorithm is effective in evaluating total distortion when accurate and aligned reference signals are available. But the harmonic metrics cannot evaluate many artifacts that are characterized as buzz, squeaks, or rattles (BSR) when not coherent with the source, and the PEAQ algorithm is optimized for detecting small impairments from various general audio issues and depends on accurate time-alignment of the reference and output signals.

An alternative approach, using a difference model of time-varying loudness, is proposed. While the technique is still under development the initial evaluation shows promise for rapid evaluation of low-level distortion without the need to use a separate time-aligned reference signals. While the method needs refinement using more test samples and correlation to subjective detectability and scoring the author will present some encouraging initial results.

Speaker:
Wookeun Song received a PhD degree with a title of “beamforming applied to psychoacoustics” in Aalborg University in 2008. He has 24 years of experience in research and development related to microphone array techniques, sound quality, audio quality, multi-channel sound reproduction, electroacoustics, machine learning and environmental source classification. He has participated in several national and international research projects and has supervised a number of Master’s students in collaboration with Technical University of Denmark (DTU) and Aalborg University (AAU). He has published several scientific papers in diverse journals and international conferences.

10:00-11:00 AM PST

Audio manufacturers often make large investments in engineering staff and professional test equipment for design and validation. The audio enthusiast community has taken an increasingly keen interest in the kinds of audio measurements performed by these engineers in their labs. As a result, an increasing number of enthusiasts are assembling measurement systems and posting their audio measurements on forums and blogs.

Speaker:
Jude Mansilla founded Head-Fi.org in 2001 as a hobby website and forum discussing premium headphone audio. Since then Head-Fi has grown to become the world’s most visited website dedicated to premium audio, and the launch point for many products in the category. The Head-Fi community, with its millions of unique visitors, has played a significant role in defining and expanding the market for high-end personal audio products globally. Head-Fi also produces CanJam Global, the world’s premier headphone and personal audio expo, with CanJam shows in New York City, Singapore, Shenzhen, SoCal, London, Chicago, and Shanghai. Head-Fi also has a state-of-the-art audio measurement lab at its office in Livonia, Michigan.

11:00 AM -12:00 PM PST

A series of controlled listening tests have identified a preferred target response for around-ear (AE), on-ear (OE) and in-ear (IE) headphones that satisfy the majority (64%) of listeners. Two smaller segments of listeners prefer this target response with slightly more (15%) or less bass (21%). Two statistical models have been developed that predict listeners’ sound quality preference ratings of a headphone based on how much its measured magnitude response deviates from these target responses. My talk summarizes this research, and presents some new research related to how headphone measurements vary across different test fixtures including the B&K 5128. The goal is to be able to model and predict listeners’ preference ratings of a headphone using measurements from different test fixtures.

Speaker:
Sean is a Senior Fellow, for the Intelligent Audio group at Harman International, a major manufacturer of audio products for consumer, professional and automotive spaces. His research focuses on improving quality of sound reproduction across all three spaces. Prior to 1993, he was a research scientist at the National Research Council of Canada where his research focused on the perception and measurement of loudspeakers, listening rooms, and microphones. Sean received a bachelor’s in music from the University of Toronto, and his master’s and Ph.D. degrees in Sound Recording from McGill University in Montreal. He has written over 50 research papers on the perception and measurement of audio for which he was awarded the Audio Engineering Society (AES) Fellowship Award in 1996, two Publication Awards (1990 and 1995) and best peer-reviewed paper award at AES 143rd. in 2017. In 2013 he was awarded the ALMA Titanium Driver Award for scientific contributions to the loudspeaker and headphone industry. In 2019, he received the Harman External Leadership Award. Sean is an AES past President.

1:00-2:00 PM PST

Ongoing advancements in MEMS fabrication processes has resulted in a new micro speaker using piezoelectric materials to actuate an acoustic structure. The radiating surface or membrane has several desirable attributes including, stiffness/rigidity, light weight, high break-up, fast transient response, low thermal expansion and moisture/humidity resistance.

Packaged in a familiar semiconductor housing, these piezoelectric MEMS micro speakers are SMT reflowable on flex/PCB or can be soldered with leads. Full Hi Resolution/HD audio with 20 Hz to 20 kHz bandwidth in achieved in an occluded earbud design. This presentation will detail the challenges of making audio measurements with piezoelectric MEMS micro-speakers using a B&K Type 3670 8×2 Audio Interface with a Type 4157 IEC711 coupler and Type 4620 high frequency ear simulators. Test equipment selection, audio lab requirements, raw transducer testing as well as systems-level testing will be detailed. Also, acoustic tuning guidelines for integrating piezo-MEMS micro-speakers into wired and TWS earbuds will also be shared.

Speaker:
Michael Ricci is the Director of Electroacoustic Engineering at xMEMS Labs, in Santa Clara, CA. His background is semiconductor and MEMS testing, both at wafer-level and as packaged devices. Mr. Ricci has held Senior FAE and Principal Electroacoustic Engineering positions with Bosch Sensortec (Akustica) and Knowles Electronics supporting MEMS transducer and balanced armature integrations for strategic accounts. Accreditations include PMI Project Manager (Silicon Valley Chapter) and Certified ProTools Engineer. Industry associations include IEEE Audio Engineering Society, Acoustical Society of America, Project Bar-B-Q Audio-Thinktank, NAMM, and ASCAP.

2:00-3:00 PM PST

This presentation will describe the measurements that assess the acoustical qualities of rooms. We will take a journey, from noise isolation to speech intelligibility, what they mean and how they are best assessed, and where your targets should be, based on the function of the room.

Speaker:
Jim joined Bruel & Kjaer in 1983 and served many roles with the company. Currently Jim serves as the Manager Inside Sales – HBK North America and is the Product Specialist for Hand-Held Instrumentation, and is an application in Acoustics, Audio & Environmental Noise. He is currently a member of the ASA, AES, ASTM, SAE.

Track 4: Ear Simulators, HATS Technologies and Non-Contact Transducers

9:00-10:00 AM PST

The multimedia evolution has led to full audio bandwidth performance in new generations of smartphones, headsets, headphones, as well as hearing aids. This calls for wider band performance of the ear simulators, and head and torso simulators used by the industry to evaluate these multimedia devices, which in return calls for a better understanding of the high frequency behavior of the human ear, that these simulators are supposed to replicate. Specifically the human ear canal that couples the external sound field to the eardrum and the solid parts of the middle ear. Acoustic input impedance measurements are an important parameter when characterizing ear simulators and the human ear. Today, this is quite well covered up to around 8-10 kHz. This session take a look at a unique measurement technique developed to enable wideband acoustical impedance measurement in the full audio band up to 20kHz. First the technique is used to obtain measurements on the widely used IEC711 ear simulator and compared to detailed simulations. Then the technique is applied on human subjects by including the first of its kind in vivo based magnetic resonance imaging study of the human ear canal. Masurements results of 32 subjects is presented and the mean human impedance is also found by propagated the measurements is each ear canal to a common reference plane across all subjects.

10:00-11:00 AM PST

For the ear simulators that have been developed over the last 60 years the acoustic impedance and the geometry of the ear simulator have been the primary focus in addressing the increasing need for realistic, accurate and repeatable acoustic measurements. The session presents a new and standardized fullband ear simulator that provides unprecedented realism in audio testing, reduces the development time for new acoustic product and ensures product audio quality in the marketplace.

Speaker:
Lars Birger Nielsen, born in 1959 in Roskilde, started his academic studies of electrical engineering at the Technical University of Denmark in 1979. His professional career began in 1985 when he joined Brüel & Kjær in Nærum. He is mainly involved in electroacoustics, psychoacoustics as well as measurement technology relating to speech transmission quality and hearing simulation. He is active in ITU-T, ETSI, 3GPP, IEEE, and IEC and is chairman of ITU-T SG12 WP1. He is also Rapporteur for the Q5 working group in ITU-T SG12. His fields of interest and research are in acoustic measurement technology, loudness assessment, auditory tests, speech and audio quality evaluations.

1:00-2:00 PM PST

Laser Doppler Vibrometry is a non-contact vibration measurement technique that allows engineers to visualize the response of nearly any electroacoustic device including loudspeakers, exclosures, consumer audio devices, mobile devices and consumer electronics. This session will introduce Optomet SWIR Laser Vibrometer technology, cover the measurement principle and present several electroacoustic applications for Vibrometry.

Speaker:
Tobias Ban has been in the Sound and Vibration industry for over 20 years. He has spent 15 years specializing in Laser Doppler Vibrometry for non contact vibration testing. He is the president of Vibrations Inc. in Anaheim, CA and responsible for the distribution of Optomet Laser Vibrometers in North America.

2:00-3:00 PM PST

In this presentation, a brief introduction to Head-Related Transfer Functions (HRTFs) and its importance will be presented first. In order to create a truly immersive sound experience, it is critical to measure accurate HRTFs. We describe in detail the measurement process using the B&K 4128C Head and Torso Simulator, and the B&K 4101 binaural microphones for measurements on humans. In addition, perceptual experiments to validate these measurements will also be explained. We will also introduce Embody’s proprietary Immerse technology and its real-world applications that computes HRTFs real-time with a single image of your ear.

Speaker:
Dr. Kaushik Sunder currently heads the overall Engineering efforts and also leads the Audio and Acoustics Research Team at EMBODY. Kaushik has spent a great deal of his research career in the field of 3D Audio and Psychoacoustics. Over the last few years, his research has focussed on understanding the importance of personalized HRTFs particularly for headphone playback of spatial audio.

Prior to working at Embody, Kaushik served as a Research Scientist at Ossic and as a Postdoctoral Researcher at the Sound Recording Department, Schulich School of Music at McGill University. He is also a visiting research scientist at the Human factors department at NASA Ames Research Center. Kaushik received his PhD from the Digital Signal Processing Laboratory, NTU Singapore. He has regularly authored articles appearing in the Journal of Acoustical Society of America, IEEE Signal Processing Magazine, Journal of Audio Engineering Society, and AES International Conventions.