New HDMI Forum Version 2.1 Specification Is Good News for Audio
Initially unveiled at CES 2017, Version 2.1 of the HDMI Specification is now published and brings more than just support for resolutions up to 10K and Dynamic HDR. In fact, HDMI 2.1 is a huge leap forward, introducing a new Ultra-High Speed HDMI Cable, which also supports Enhanced Audio Return Channel (eARC), multichannel uncompressed 24-bit/192 kHz audio, and support to advanced audio formats - including DTS Master, DTS:X, Dolby TrueHD, Dolby Atmos, and more.   Read More

XMOS Extends Portfolio of Far-Field Voice Capture Solutions with New xCORE VocalFusion Speaker Linear Evaluation Kit
XMOS announced commercial availability of the xCORE VocalFusion Speaker Linear evaluation kit as part of its range of innovative far-field voice capture solutions. Based on the XMOS VocalFusion XVF3100 voice processor, the kit is designed for developers, OEMs, and ODMs integrating voice user interfaces into flat or linear consumer electronics typically found at the "edge of the room," such as smart home control panels and washing machines.   Read More

Vesper Launches High-Performance VM2000 Microphone for Smart Speakers
Vesper announced its newest VM2000 high-performance piezoelectric MEMS microphone, targeting microphone arrays used in voice-activated systems such as smart speakers, smart home, and Internet of Things (IoT) products. According to Vesper, the VM2000 enhances voice capture and clarity, while ensuring long-term voice performance in harsh environmental conditions and maintains high system performance over the life of a product.    Read More

Meyer Sound Expands LEO Family with VLFC Very Low Frequency Control Element
Meyer Sound has announced the introduction of the VLFC very low frequency control element, the latest addition to Meyer Sound's LEO Family of line array systems. VLFC is the first large-scale loudspeaker system specifically engineered to create visceral impact at frequencies below the threshold of hearing. By focusing energy into a narrow band between 30 Hz and 13 Hz, VLFC is uniquely capable of generating extreme variations in air pressure that are sensed by the entire body as compression waves while those frequencies at the upper end of its range are perceived as thunderous bass sound.   Read More

OPPO Digital Announces Support for MQA with Update for UDP-205 Blu-Ray Player 
The OPPO Digital UDP-205 is a universal disc player specifically designed for audio performance, providing reference level sound quality for 4K Ultra HD Blu-ray and many other digital audio and video formats. In many ways, it is the perfect audio source device for today's audio enthusiasts. Now, the latest firmware update to the UDP-205 adds MQA decoding to the UDP-205's digital audio file playback, thanks to the recently established partnership between the two companies.   Read More

Hefio Joins Forces with Genelec and IDA Audio to Advance Individual Calibration for Demanding Headphone Applications
Following the recent joint-venture announcement between Finnish HRTF modeling specialists IDA Audio and Genelec, another company from Finland now joins the effort to provide personal calibration on headphones. Finnish startup Hefio Oy, announced a strategic partnership with Genelec and IDA Audio to develop personal optimization for headphones. Together, the three companies now form a world-class research alliance, with the ambition to discover and deliver realistic immersive audio experiences for headphone users.   Read More

TIDAL Implements Album Loudness Normalization and Activates It by Default for Mobile Players
Always looking to differentiate its music streaming service with higher quality experiences, TIDAL has adopted the loudness recommendations of Eelco Grimm, HKU University of the Arts Utrecht and Grimm Audio. In TIDAL's recent update of its iOS and Android apps, loudness normalization is now turned ON by default. With this move, TIDAL follows the trend towards automatic loudness normalization that was initiated by Spotify and YouTube.   Read More

HEAD acoustics Introduces High-Precision HRT I Measurement Turntable
HEAD acoustics launched the HRT I (HEAD acoustics Remote-operated Turntable), a high-precision turntable enabling users to perform automated, orientation-dependent acoustic measurements. The rotation unit of the turntable offers a 360° rotation range, which can be approached in 0.1° steps, allowing manual or automated measurements. And it can support large devices under test with up to 50 kg!   Read More

Mike Klasco

Guest Editorial

Exploring Graphene Speaker Development

In a previous article (see The Audio Voice 154), we explored the work of ORA Sound in development of GrapheneQ, a graphene oxide the company is commercializing in composite speaker diaphragms - and is already under implementation in headphones. This week we focus on the research and development by GraphAudio. The company is developing a complete implementation of a true electrostatic where the pure graphene diaphragm functions as part of the "motor."

In 2012 at the University of California, Berkeley, Dr. Alex Zettl and Dr. Qin Zhou were researching graphene for audio applications. About a year later, a proof of concept graphene earphone was demonstrated and received a lot of press coverage. The in-canal earphones consisted of a graphene diaphragm sandwiched between electrodes that created the electrical field. When this field oscillates due to the audio signal, it causes the graphene to vibrate in a physical analogy to the audio electrical signal and this generates sound. It's essentially an electrostatic or planar speaker; but instead of a metalized polymer film diaphragm, graphene is used. The graphene diaphragms are very thin and light with a small spring constant so that the air itself damps its motion. The air-damped graphene converts almost all of its energy into sound and is potentially extremely efficient. Scholarly work has continued but a number of practical challenges remain before graphene can emerge as a viable - and game changing - alternative for established transducer technologies.
In my previous article, I mentioned that in 2016 GraphAudio was founded and licensed the graphene audio work and patents from The Lawrence Berkeley National Labs at UC Berkeley. With both the rights to the audio work and IP as well as the original research team of Zettl and Zhou, they began to hire other specialists and continue the path to commercialization. Business founders are Fred Goldring, CEO, and Frederick Wells, Chief Business Development Officer. Lorance (Lonnie) Wilson, CTO and VP Engineering has long experience in semiconductor processing and commercialization of new technologies at Fairchild, AMD, and Intel, and leads the development efforts.
GraphAudio's goal is to develop a new generation of graphene-based micro audio componentry that potentially will outperform the current generation and open new capabilities. GraphAudio's patent-pending true graphene transducer delivers an electrostatic micro speaker that promises high-resolution audio with high sensitivity and ultra-low distortion.
Single die exploded view stacked: Electrode 1, Spacer 1, Graphene, Spacer 2, and Electrode 2. The pure graphene transducer design functions as speaker or microphone, or both, but the diaphragm tensioning, electrode spacing, and bias voltage, among other parameters such as sensitivity vs. Xmax excursion, electrode attach technique, etc. still must be optimized for full functionality.

The obvious targets for graphene-based audio components range from speakers (e.g., tweeters and microspeakers) to earphones/headphones and microphones. The promise for audiophiles is that graphene's high strength allows for the relatively large, free-standing diaphragms necessary for effective low-frequency response, assuming traditional planar dipole configuration. Due to the intrinsically low moving mass and high Young's modulus, achieving high-resolution audio is a given. The symmetrical push-pull electrostatic drive has been the core technology of the finest audiophile headphones and speakers and studio microphones (readers know the reputation of the Sennheiser Orpheus and Stax electrostatic headphones, Neumann studio condenser mics, and a number of legendary electrostatic speakers). The development work being done by GraphAudio is integrating pure graphene diaphragms for higher sensitivity with much better form factors than current electrostatic implementations using polymer film (metalized or otherwise conductive coating diaphragms).
In theory, graphene transducers can be economically produced in high volume utilizing automated fabrication techniques. With any new technology, moving from the laboratory into the real world is the challenge. Just understanding and learning how to control the fabrication processes for optimization of the usual parameters are the hurdles GraphAudio is just beginning to get under control. The measurement and full characterization of the transducer is where much of their focus lies, including optimization of amplifier parameters, bias voltage, as well as transducer excursion, response, tensioning, and sensitivity trade-offs. The low hanging fruit are microphones, tweeters, earphones, and headphones due to the low excursion requirements-but winning the lottery means microspeakers.

GraphAudio's Harry Chou working at Chemical Vapor Deposition (CVD) system to deposit Graphene Film.

Goldring expressed his passion for the project saying, "Graphene transducers are the holy grail of audio and our goal is to become the standard for microspeakers and microphones inside every connected device on the planet. With more and more people today (and the vast majority of young people) listening to their music on mobile devices and in-ear buds rather than large bookshelf and floor speakers, our graphene transducers will finally bring high-res audio economically to the masses. GraphAudio's transducers will introduce the first quantum leap in consumer audio technology since the advent of the moving coil, magnetic, dynamic speaker in 1921. For an entire generation which has been weaned on compressed music heard only through marginal earphones, our graphene transducer technology will be a real 'ear opener.'"
GraphAudio envisions arrays of these transducers enabling control of directivity and coverage, but also audiophile applications for full range dipole speakers. Certain product categories will be available for licensing while others will be reserved for GraphAudio's own products.
The Audio Voice will keep our readers updated regarding graphene developments. Also look for a feature article in the February 2018 edition of audioXpress magazine

Clarification on TDK-InvenSense MEMS Microphone Business
TDK-InvenSense has requested to clarify that the company has "no roadmap that plans to fade away its mic product line." On the contrary, TDK-InvenSense's analog and digital microphone portfolios are built on a strong heritage of industry firsts, including continuous improvement of MEMS microphone SNR, ever-higher integration levels, and even lower power consumption. The next generation of InvenSense microphones fit in all mobile and IoT applications where low power, high fidelity, tight sensitivity matching and high acoustic overload point (AOP) are important. TDK-InvenSense is committed to continually pushing forward new microphone products and solutions that meet the needs of our OEM partners and the industry at large.


You Can DIY!
Willow Revisited: A Design Celebrating the Enthusiasm and the Creativity of the Builder
By Robert Nance Dee
audioXpress December 2011 introduced readers to Willow, a "proof-of-concept" project featuring a PMBF4393 JFET and HA5002 buffered preamp, built as a companion to the author's 5002 power amp, and the first to use this typology. After considerable positive DIYer feedback, the Willow was revised and updated, and this article, "Willow Revisited" was published in February 2016. More recently, audioXpress January 2018 features another revised and much perfected take on this tube hybrid design - the new 6922 Amplifier, where author Robert Nance Dee states he "saved the best for last." But since the first Willow project was already available online, we thought our readers would like to review the "Willow Revisited" as well before exploring the author's latest 6922 design.   Read the Full Article Now Available Here

Voice  Coil Test Bench
The New D4400Ti-Nd Compression Driver from PRV Audio 
By Vance Dickason
For this Test Bench, Voice Coil characterizes a new compression driver from Brazilian pro sound OEM PRV Audio, a company that started operations in 2006. It was created by a group of former executives and engineers from one of Brazil's most prestigious loudspeaker manufacturers, and continues to produce high-quality products. This edition of Test Bench looks at the recently released D4400Ti-Nd compression driver, complemented with PRV Audio's WGP22-50 2" bolt on 60° × 60° waveguide. The D4400Ti-Nd is the latest in a series of 2" throat 4" diameter voice coil compression drivers, which includes also the D4400Ti, and the D4400Ph. Features for the PRV Audio D4400Ti-ND include a titanium diaphragm driven by a 4" voice coil wound on a Kapton former with copper-clad aluminum wire (CCAW). Other features include a cast-aluminum body, a 200 W rated power handling (400 W program material maximum), a neodymium ring magnet motor, field replaceable diaphragm, 110 dB sensitivity, minimum crossover frequency of 1.6 kHz, and color-coded push terminals. The horn supplied with the D4400Ti-ND compression driver is PRV's WGP22-50 injection-molded ABS waveguide with a 1.4" throat. The WGP22-50 is a 60°H × 60°V round horn with a low-frequency limit of 800 Hz. This article was originally published in Voice Coil, May 2017.   Read the Full Article Online

AX December 2017: Digital Login
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VC December 2017: Digital Login
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