Product Design | Audio Electronics | Acoustics | DIY | Audio Innovations
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Loudspeaker Industry Sourcebook 2021 Now Available Online! |
In the best tradition of the Loudspeaker Industry Sourcebook (LIS), the 2021 edition contains company listings and so much more. In this edition, readers will find several must-read articles from some of the finest industry leaders and interviews with audio professionals on trending industry topics. Visit the LIS website for the listings and gotomylis.com for the full online edition! Read it Online or Download it, it's Free and it's Here
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DSP Concepts Adds THX Spatial Audio to Audio Weaver Development Platform |
With the audio industry apparently determined to push forward the evolution toward spatial audio reproduction, manufacturers need tools to add the experience to their new product designs. Starting now, brands building on Audio Weaver can easily deploy THX Spatial Audio to bring immersive sound home entertainment devices to market. The partnership adds valuable new IP to DSP Concepts' library of 500 market-proven Audio Weaver modules. Read More
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Bryston Joins Azione Unlimited Following Acquisition by James Tanner |
Bryston, the manufacturer of audio electronics and loudspeakers for music and cinema systems, has joined the Azione Unlimited buying group serving audio/video integration professionals. The company from Peterborough, Ontario, made the announcement following the recent acquisition of the business by James Tanner, now the company CEO. Tanner already confirmed the intention to fortify relationships with A/V specialty dealers and expand Bryston's R&D and manufacturing . Read More
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Jacoti Announces OTC Ready Technologies for Over-the-Counter Hearing Aid Development Using Qualcomm 51XX SoCs |
Following the announcement of collaboration with Qualcomm, in October 2020, Jacoti BV, the Belgium-based medical technology company, has now announced the immediate licensing availability of OTC Ready, Jacoti’s hearing software platform. OTC Ready enables headphone/earbud manufacturers using Qualcomm 51XX SoCs to address the likely requirements of the upcoming US over-the-counter hearing aid market. Read More
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Audio Precision Releases APx500 Version 6.1 Audio Measurement Software |
Audio Precision (AP) has released the APx500 audio measurement software, version 6.1. With this update, AP is adding new measurement results, options, and test signals for production test of loudspeakers, headphone drivers, and microphones. Most importantly for speaker designers and manufacturers, the new APx software now offers the broadest set of methodologies available for detecting rub and buzz defects. Read More
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Sennheiser Introduces Evolution Wireless Digital Microphone Systems for Corporate and Education Spaces |
Sennheiser designed the new Evolution Wireless Digital, offering a professional wireless microphone system that is easier to use, based on an easy, app-based process, while retaining all the multichannel capability and reliability that users have come to expect of UHF and 1G8 microphones. The different systems are ideal for corporations and schools where users have to set up audio for themselves . Read More
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Sonos Releases pyFLAC Library for Real-Time Lossless Audio Compression in Python |
FLAC is the most universal compression algorithm for audio, allowing users to maintain a perfect reconstruction of the original data. As an audio manufacturer that supports FLAC in all its home audio (Wi-Fi) products, Sonos decided to improve its own development tools by creating an efficient alternative to using the original FLAC library (libFLAC) written in C, and created a Python implementation for FLAC encoding/decoding focusing on real-time streams. pyFLAC is now available as a free-to-use package . Read More
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Heavenly Soundworks to Showcase FIVE17 Loudspeaker System at T.H.E. Show 2021 |
So many audio manufacturers have kept busy during the global pandemic but have yet to publicly demonstrate the results of their work. Heavenly Soundworks is a new US brand, which will officially debut the FIVE17 Loudspeaker System at T.H.E. Show 2021, June 11-13, at the Hilton Long Beach Hotel, Long Beach, CA. This will be the first chance to listen to this new active loudspeaker design, the work of Kevin and Jonathan Couch, the company’s co-founders . Read More
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Guest Editorial
Mike Klasco
(Menlo Scientific)
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xMEMS Piezo Microspeakers
The Future of Direct-to-Consumer Hearing Health Devices
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Over-the-counter (OTC) hearing aids are a new product category that consumers will soon be able to buy directly from brands that we all associate with consumer lifestyle products, such as the recently announced Bose SoundControl product. Intended for adults who believe they have mild-to-moderate hearing loss, OTC hearing aids will be regulated as medical devices by the US Food and Drug Administration (FDA). There is also an existing category of assisted hearing devices, personal sound amplification products (PSAPs), bridging gaps between medical hearing aids and consumer earbuds
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Qualcomm is working with Jacoti, an audio technology company focused on hearing enhancement, to bring Jacoti’s medical-grade algorithms to the Qualcomm QCC5100 Series Ultra-Low Power Bluetooth SoCs. |
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The reality is that there is a continuum between personal amplification, which is little more than a mic, amplifier, and earphones, to the sophisticated and expensive hearing aids that are professionally prescribed and fitted. For moderate-to-severe hearing loss, there is no replacement for a proper hearing assessment and fitting for a real hearing aid and custom ear mold. However, there is an infinitely larger market for OTC devices for the moderately hearing impaired. Also, OTC apps, after users complete the self-assessment, can indicate when moderate measures are not enough and it is time to visit an audiologist. See Table 1 below for a comparison of the various device tiers.
The next generation of these OTC and direct-to-consumer devices must include not only legacy hearing aid features but also TWS consumer earbud features, including Bluetooth and possibly active noise cancellation (ANC). Several challenges are presented when trying to combine the compact, consumer-friendly form factor of TWS with hearing assistance features into a single product.
Challenge 1 – Form factor
The first challenge is finding balance to achieve that small, in-ear TWS form factor while also delivering operation times somewhere in between TWS and a medical-grade hearing aid. Fitting large, thick dynamic driver (DD) transducers together with larger batteries required for extended operation time is difficult. Also challenging is managing magnetic sources in close proximity to RF Bluetooth antennas.
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In 2018, Bose was the first company to receive an FDA approval for an over-the-counter (OTC) hearing assistance device. In 2021, Bose finally unveiled the SoundControl Hearing Aids, which are self-fitting, direct-to-consumer hearing-aids. |
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Challenge 2 - Tuning for Individual Hearing Loss Needs
With medical-grade hearing aids, audiologists have the luxury to mix and match a variety of Balanced Armature (BA) drivers to deliver a unique frequency response tuned to the specific hearing loss profile of an individual consumer. This is very much a custom product. For OTC, there is no such structure. A single driver must be flexible enough to adapt to the hearing needs of millions of unique consumers. OTC products include a self-assessment app that runs the consumer through a series of tests to identify with which frequencies the consumer requires assistance. Then a custom equalization (EQ) profile is applied via DSP to the transducer to deliver the desired sound profile.
For this consumer-driven method to work, the OTC vendor requires a speaker/driver with a sufficiently flexible frequency response to adapt to many combinations of low, mid, and high frequency hearing loss. This can be challenging for a single-configuration (single SKU) product, where one transducer must have the flexibility to serve all hearing profile needs.
Further, once the product depends on DSP and parametric EQ for tuning, developers must also care about driver-to-driver variations in frequency response. A wide variation (+/-3dB or more for typical coil-based transducers) will make it difficult for the EQ to always have the desired effect. This can be overcome with driver matching and calibration at assembly, at the expense of test time and cost.
Challenge 3 – Comfort Without Listening Fatigue
Finally, OTC product designers need to achieve a balance in listening comfort. An OTC product may not be worn for 18 hours like a medical-grade hearing aid, but wear may regularly exceed that of the average TWS use case. Two key measures of long-wear comfort include ear canal pressure mitigation and the overall weight of the product as it rests inside or hangs on the ear.
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Table 1: Comparison of medical and non-medical hearing devices currently available in terms of need for specialist consultation, regulatory requirements, minimum labeling requirements, and population targeted as adapted from National Academies of Sciences, Engineering, and Medicine (NASEM). Source: Hearing Review, July 2020 by Anne D. Olson, PhD, David Maidment, PhD, and Melanie Ferguson, PhD. |
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Piezoelectric MEMS Microspeakers
Just as integrated circuits were a key building block to the modern hearing aid, there are new components that will enable augmented hearing in TWS form factors. What is interesting is that again it is an integrated circuit... specifically, a new class of microspeakers now available that may enable both easier earbud design and manufacturing while at the same time enabling broad, wide-bandwidth frequency response tuning to any type of hearing assistance need all from a single, non-custom, mass-manufactured earbud.
xMEMS Labs, a California startup with an experienced team of microelectromechanical systems (MEMS) specialists and audio veterans from Apple, Knowles, InvenSense, and Forte Media, is targeting over-the-counter hearing augmentation enhanced earphones in addition to the traditional consumer TWS market.
MEMS microspeakers have trailed behind MEMS microphone commercialization by two decades due to materials and fabrication challenges, but now, with the emergence of thin-film piezo materials, MEMS microspeakers can actuate more quickly and with greater precision than traditional coil-based transducers, enabling production of high-fidelity audio. Today, devices from xMEMS deliver a combination of audio fidelity, size, and speaker-to-speaker uniformity that is not possible with traditional voice coil (DD or BA) approaches.
xMEMS introduced its Montara microspeaker in July 2020. The entire speaker (actuator and diaphragm/membrane) is manufactured in a high-precision, highly consistent monolithic silicon process (<10 layers). The net result is a very thin slim speaker (1mm thin) that consumes approximately 50mm3 area and weighs less than 80mg. Future derivatives will achieve sub-30mm3 area, enabling Receiver-in-Canal (RIC) implementations. But it is not just the fabrication of the transducers, but the promise of automated pick-and-place of MEMS speakers for surface-mount technology (SMT) board stuffing. While SMT circuit board construction is not used for most prescribed hearing aids, multi-layer SMT is common for TWS devices. For placement flexibility within the earbud housing, Montara offers two SMT-ready package options: top-firing and side firing.
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xMEMS Montara top-firing and side-firing packages. The thin profile enables a reflow to a PCB/flex module or side-firing placement opening up significant space for larger batteries and longer operation times. Montara is non-ferrous, eliminating magnetic interference with Bluetooth antenna or other RF components. |
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As with medical-grade hearing aids, consumers will have certain expectations of robustness for a device that must survive everyday wear-and-tear and a variety of environmental conditions. Traditional BAs and dynamic drivers require special accommodations for water and particle ingress protection. Therefore, it is best practice to design in a protective mesh or acoustic vent to protect the transducer, much like protecting a MEMS microphone. The xMEMS monolithic piezoelectric microspeaker has an IP-58 rating at the wafer level. Each die (and the finished, packaged transducer) can survive water and particle ingress. Finally, there is the physical robustness (10,000g) so showering, sport activities, and even swimming are all possible.
And MEMS speakers are voltage-driven, capacitive devices and are extremely power-efficient. Opportunities exist in the future to pair them with amplifiers capable of energy recycling to further extend operation time beyond what is possible today from even the most efficient BA.
Finally, the acoustic uniformity of MEMS earphones enables viable self-assessment tuning. Fabricated using a monolithic MEMS semiconductor process, xMEMS' Montara creates unprecedented transducer-to-transducer consistency (+/- 1.5 dB variation), which eliminates calibration and driver matching common with coil-based drivers. The xMEMS speaker utilizes a silicon diaphragm that is rigid while damped, ideal for OTC occluded hearing augmentation applications.
As highlighted in the Figure below, the linear response without resonance of the xMEMS transducer rises smoothly above 800Hz to beyond 20kHz, to achieve near infinite frequency response curve configurability when using equalization. Up to 30dB of gain is available in the upper octaves to aid high frequency hearing loss scenarios and to support improved speech intelligibility, presence, and clarity. An EQ setting, such as a Harman curve, can be applied to the xMEMS solution and be further converted into biquad coefficient sets, the more accessible format for DSP, to also deliver the similar frequency response.
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Raw Frequency Response Comparison (xMEMS and Typical BA Receiver) |
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Most important, the smooth phase, fast transient settling time, and extra upper octave amplitude allow for a significant increase in gain and bandwidth without feedback compared to balanced armature transducers or any of the 6mm diameter dynamic earphone drivers. Specifically, the resonance-free response of the xMEMS earphone speaker enables the self-assessment remedial compensation to work better than BAs – as hearing-aid fitters know all too well the skill needed to precisely tune BAs for clients.
Some OTC hearing augmentation earphones are targeting both higher speech intelligibility, but also enhanced music and movie listening experiences. As the xMEMS device is free of the high Q resonance of the BA drivers, hearing compensation well past 8kHz is possible. Beyond enhanced speech augmentation, the device's fidelity offers unique attributes of musicality to hearing aids.
From the user’s perspective, listening fatigue may be the most perceived benefit of xMEMS microspeakers due to the integrated venting. Montara’s silicon speaker membrane (equivalent to diaphragm) is vented with microscopic slits so a pressure differential pathway exists between front volume (ear canal) and the back volume of the speaker without negatively impacting low frequency response. The back-volume housing is often open to the outside with a vent so a secondary vent for over-pressure protection may not be required.
And the fact that MEMS microspeakers eliminate the coil and large magnet of traditional dynamic drivers leads to a much lighter earbud (60% lighter than a typical RIC BA receiver), which will reduce strain on the ear and improve long-term comfort.
In summary, MEMS microspeakers promise to break the last remaining barriers to shrinking the OTC hearing augmentation devices, increasing comfort, while adding features and extending battery life. Most significant are improved speech intelligibility, presence, and higher gain before feedback, conferred from the extended and smoother mid/high frequency response. Additionally, the acoustic uniformity of MEMS earphones enables viable self-assessment tuning. xMEMS devices and evaluation kits are sampling to manufacturers now, with mass production already scheduled in 2021.
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Summary of MEMS Speaker Advantages for Hearing Health Devices |
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Transforming Listening Experiences
on the Move with New Technologies
By Meridian Audio
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Originally published as part of the Automotive Audio Solutions Market Update feature in audioXpress June 2021, this article offers an overview on how British audio pioneer Meridian Audio is transforming listening experiences with new technologies for the car. For more than 10 years, Meridian has built a strong presence within the automotive market, with outstanding recent examples available for McLaren Automotive, Jaguar Land Rover, Human Horizons, Rivian, and Kia. The article details the company's approach with 3D surround sound and immersive in-car audio systems that combine all its digital processing solutions. This article was originally published in audioXpress, June 2021. Read the Full Article Now Available Here
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The Secret Life of Plastic Film Diaphragms
PEEK High-Performance Film Diaphragms and Cones for Headphones and Speakers
By Mike Klasco (Menlo Scientific)
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This article explores the use of high-performance film diaphragms for headphones and speakers. Having worked as a consultant for multiple material science companies involved in research for the loudspeaker industry, Mike Klasco is in a position to share real-world knowledge about the use of these plastic-based formulas in the most critical component for sound quality, which is the diaphragm. The article takes a closer look at Polyetherether Ketone (PEEK) and provides comparisons with the PEI (polyetherimide) and polyethylene naphthalate (PEN) developments, and even standard PET formulas that dominate most cheap earphone and headphone diaphragm applications. The article also references key product implementation and the latest knowledge directly sourced from vendors and patent holders, such as DuPont, Teijin, and Victrex. This article was originally published in Voice Coil, May 2021. Read the Full Article Now Available Here
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Advancing the Evolution
of Audio Technology
audioXpress features great articles, projects, tips, and techniques for the best in quality audio. It connects manufacturers and distributors with audio engineers and enthusiasts eager for innovative solutions in sound, acoustic, and electronics.
Voice Coil, the periodical for the loudspeaker industry, delivers product reviews, company profiles, industry news, and design tips straight to professional audio engineers and manufacturers who have the authority to make powerful purchasing decisions.
The Loudspeaker Industry Sourcebook is the most comprehensive collection of listings on loudspeaker material in the industry. Purchasers and decision makers refer to the guide for an entire year when making selections on drivers, finished systems, adhesives, domes, crossovers, voice coils, and everything in between.
© 2021 KCK Media Corp. All Rights Reserved.
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