Industry & Product News
Commentary: CTA Confirms CES 2021 Will Be a Digital-Only Virtual Experience
The Consumer Technology Association (CTA) has announced that CES 2021 - January 6-9, 2021 - will be an all-digital experience. Meaning, there will be no CES 2021. There will just be more webinars and online "things," which no show promoter has currently discovered what they are, who they are for, and how much they are worth. Certainly not for a strong B2B show like CES. Anyway, given the global pandemic situation, it was predictable .    Read More  
New Vesper VM3011 Piezo MEMS Microphone with Adaptive ZeroPower Listening Extends Battery in Voice-Activated Designs
Vesper introduced its new VM3011 intelligent digital microphone featuring a new power-saving architecture that enables a 10x extension of battery standby life, combined with best-in-class acoustic performance. Significant to manufacturers, the VM3011 is an IP57 device, resistant to dust and moisture and doesn't require a protective mesh, which allows preserving key acoustic performance metrics (e.g., sensitivity and SNR) at the system level, ideal for voice-activated smart home designs and wearables .    Read More  
Duolink Go Introduces SpeakerBuds True Wireless EarBuds and Portable Speaker All-In-One Concept
Start-up company Duolink Go just launched its first product campaign on Kickstarter with an interesting design concept. Duolink Go debuted the world's first SpeakerBuds all-in-one design, combining true wireless earbuds and a two-part charging case with in-built speakers. The product differentiation is actually smart, since it offers a larger battery and charging case for TWS, which also serves as a single compact Bluetooth portable speaker or a separate (stereo) pair when opened .    Read More

NEXO Introduces ID14 Cube Point Source Loudspeaker and ID S108 Subwoofer
Taking its reputation for impressive power-to-size ratios to a new level, NEXO has unveiled the smallest loudspeaker ever built by the company. The new ID14 is a 5-inch cube, capable of 116 dB SPL (peak). Partnered with its ID S108 subwoofer box, it creates an extremely compact high-power three-way system. Available in black, white, or any RAL color, the ID14 can be used standalone or in a distributed system, for front fill, infill, or delays. For installations, it can be a valuable tool to solve architectural challenges in historic buildings .    Read More  

GaN Systems Announces New Series of 12 V Class-D Audio Amplifier Reference Designs
GaN Systems, a company specialized in GaN (gallium nitride) power semiconductors, published a new technical document titled, "12V High-Efficiency Audio Reference Designs using GaN Power Transistors." The technical note was developed following the launch of the new GaN Systems Class-D audio amplifier evaluation kit and from growing customer interest for designs in the 12 V market for automotive, marine, power sports, and other applications from power system design engineers .    Read More

Dolby MS12 Multistream Decoder Now Supported and Approved on CEVA's Audio DSP
CEVA announced support for the latest Dolby MS12 Multistream Decoder on the CEVA-BX2 audio DSP. The integration provides System-on-Chip (SoC) designers and device manufacturers with a low-power, rapid time-to-market solution that will enable complete support for Dolby's latest family of formats and audio codecs, including Dolby Atmos, Dolby AC-4, and Dolby Audio. This makes the CEVA-BX2 an ideal solution for new smart TVs, set-top-boxes, and more designs, benefiting all the included audio DSP features, such as far-field noise reduction and AI speech recognition .    Read More  

New Firmware for XMOS XVF3510 Voice Processor Supports New USB Accessory Devices and Integrated Solutions
XMOS announced new firmware variants, supporting USB and built-in applications of its XVF3510 voice processor, further opening the door to voice-enabled smart product development. The two variants - XVF3510-UA for USB accessory devices, and XVF3510-INT for built-in solutions - incorporate purpose-designed algorithms that ensure a clear voice stream is captured from across the room, even in noisy environments and with audio streaming from the device itself .    Read More

Clarion Marine Launches New CMSP Premium Coaxial Speaker Line
Clarion Marine, the marine-grade audio brand that is now licensed by JL Audio for the North America, South America, Australia and New Zealand markets, announced the introduction of an all-new line of premium coaxial speakers and subwoofers for marine applications. The New CMSP speaker line features a modern design to fit a wide range of uses, with optional RGB LED illumination and excellent power handling. Offered in 6.5- and 7.7-inch, the new CMSP coaxial, full-range speakers and matching 10-inch subwoofers benefit from Clarion's decades of experience in marine audio design .    Read More  

Guest Editorial
Mike Klasco

Super-Shallow High-Excursion Speakers
Speaking of Something Completely Different...
Last week we took a quick tour of the sophisticated engineering implemented by soundmatters into the UpStage compact high-performance audio system. As discussed, the already available UPstage180 speaker was the launch platform for BDNC's high-power, flat glass woofer that uses a 0.2 mm glass diaphragm. We briefly touched on the application of the BDNC glass diaphragm, as the high-excursion yet ultra-low profile woofer in the UpStage, so this time we will drill deeper. 

From the transducer side, there are three noteworthy pillars. Starting with the ultra-thin tempered glass diaphragm, complemented with the anti-rocking thin yet high-excursion suspension, and coupled with low-end operation extended well below in-box resonance (small box eq'ed for extended bass). In this article, we will expand on those pillars.

Details of BDNC's flat-thin, long glass-composite-diaphragm woofer.

But let's step back and start at the beginning. BDNC, Ltd. began in 1995 as an R&D think tank by a Taiwan semiconductor company. The founder bought out the technology and assets in 2007, and then in 2016 raised funding from Taiwan. The core business was consulting in signal processing, mixed-signal, and electroacoustics.

With expanded resources for product development, the BDNC team was able to pursue their dream, which they call the miniMAX concept. This design philosophy is a ground-up approach for audio system development, where all the speaker design aspects are optimized using signal processing when effective. As BDNC explains, miniMAX is "a system-level technology" and an integrated approach from product design to manufacturing, applying DSP where it makes economic sense. Focusing on drawbacks that can be effectively "corrected" by signal processing while the remaining transducer parameters are concentrated on where the processing cannot mitigate performance.

BDNC considers frequency response - and with more effort, harmonic distortion - to be "DSP-friendly" while "non-DSP friendly" factors are maximum excursion ("Xmax"), specific force factor (BL/√Re), sensitivity, and power handling. If we can disregard the frequency response in the design stage, the speaker topology can be dramatically changed, allowing for thinner, more compact, high aspect-ratio rectangular or even tube-shaped products.

The well-crafted UPstage180 thin speaker design directly benefits from BDNC's flat glass speaker driver.

The smartphone and more specifically LCDs have inspired high-performance glass development. BDNC realized this new generation of high strength, ultra-thin glass from Schott, Corning, and others also has applications for speaker diaphragms. Let's take a look at some of these engineering glass formulas.

Schott AS 87 eco is an aluminosilicate glass suited for chemical strengthening (via an ion exchange treatment) that offers a high level of mechanical impact resistance and bending strength in a thickness range of 0.1 mm to 0.4 mm. Corning's Willow (available from 0.8 mm down to 0.03 mm), is roughly the thickness of a sheet of paper. Fabricated from Corning's amorphous Si O2 fusion process, molten glass is homogenized and conditioned before it is released into a collection trough with a V-shaped bottom (isopipe). Flowing evenly over the top edges, forming two sheet-like streams along the outer surfaces, the sheets meet and fuse into a single sheet which feeds into drawing equipment as it lengthens and cools in midair, as thin as 100 microns.

This process adds to the toughness of Willow (and also Gorilla) Glass and is not prone to breaks and cracks. Post processing for glass speaker diaphragm applications can include attributes such as a constrained layer damping of other materials (e.g., 3M's Viscoelastic Damping Polymer 112 acrylic polymer).

Another sophisticated element is the anti-rocking thin high-excursion suspension. The rocking problem is a known issue in high aspect ratio speakers, as there are billions of these smartphone microspeakers with the omniscient 10 mm x 15 mm x 3 mm format. While these microspeakers utilize a one-point suspension, BDNC realized that a high linearity spider was also needed, but would have to fit into a shallow form factor. The epiphany solution was actually derived from a pre-World War II field coil speaker. Specifically, a phenolic spider in a Jensen field coil speaker found in the designer's personal collection. 

A solid spring spider has better linearity performance than a cloth spider in small signals. Over the years, there have been other attempts with varying results, including Sony's low distortion old-style spider and Doug Button's EVX 1800 high output 18" pro-sound woofer, which featured a glass epoxy spider.

Achieving high excursion in shallow high-aspect-ratio transducers means fighting rocking modes (undesired rotational vibration patterns). In a number of Audio Engineering Society (AES) papers the Klippel team has explored the various rocking mechanisms and the resultant voice coil scrapes with the observation that the suspension is the main cause and cure.

Actual implementation of the glass-composite-diaphragm woofer with details of the patented design.

Rocking modes are caused by the inhomogeneous distribution of mass, stiffness, and force factor shifting the center of gravity, and electro-dynamical excitation away from the pivot point, which is the cross point of the nodal lines of the two rocking modes. Due to the high Q of the rocking resonators, only a very small asymmetrical force is required (which is usually a few percent of the transversal force) to generate a critical rocking behavior having more energy than the desired piston mode. Assessing the relative rocking level (RRL) and identifying the imbalances is a convenient way to keep voice coil rubbing under control and to avoid impulsive distortion from impairing the quality of the reproduced sound.

Woofer diaphragms vibrate through the compliances suspending the diaphragm. Compliance is the inverse of stiffness (stiffness = Young's modulus). Aside from many other considerations, the Young's modulus of the diaphragm should be as high as possible while the surround stiffness should be as low as possible.

A more compliant suspension enables the enclosure to be a smaller volume but also offers a more consistent bass response in mass production - as low-end response is dependent on the consistent back volume air compliance (air suspension) rather than variations in the surround compliance. To restate this, the resonant frequency is dominated by the effect of the back volume. This is defined as acoustic suspension (air suspension or sealed box). The compliance of the membrane must be far higher than the compliance of the back volume. 

Prototype of a new D48 glass dome diaphragm tweeter from BDNC.

Invented in 1954 by Edgar Villchur of AR speaker fame, acoustic suspension systems reduce distortion in the bottom end of the speaker's response that can be caused by stiffer nonlinear suspensions. While Acoustic Research, Inc. and Bose are odd bedfellows in the same sentence, the Bose 901 of the late 1960s used an array of 4" full range cones speakers in the tight volume enclosure and eq'ed the heck out of them below 200 Hz (almost 20 dB at 20 Hz!). So the entire bass range was used below resonance where the frequency (and phase) response was consistent and could be electrically compensated. Same here for the miniMAX approach.

On its product development roadmap, BDNC has three different sizes for its rectangular series of glass woofers. There's the middle size FP-SPK-M (160 mm x 40 mm x 17mm), the large size FP-SPK-L (584 mm x 92 mm x 25mm), and a small size FP-SPK-S (80 mm x 20 mm x 7.2mm). The next steps on the company's speaker road map are glass cone speakers (see image above), audiophile headphone drivers, and another long-term project of very low impedance (VLO) speakers.

Bass Shakers (Part 2): Motion Platforms Are Bass Shakers on Steroids
By  Mike Klasco and Steve Tatarunis
In the first part of this article, our exploration of bass shakers introduced us to haptic sensation, which adds the dimension of structure-borne vibrational energy to audio reproduction. At a concert, we see the performers, hear the music, and feel the amphitheater resonate with the bass. For home theaters, this "tactile" component adds another dimension (sometimes referred to as 4-D) to reproduce the impact of explosions, engine sounds, and thunder through by use of vibration. In this article, we will focus directly on those haptic components, including linear actuators, while revisiting other multidimensional experiences. Get out the Dramamine and prepare for the motion platforms. This article was originally published in audioXpress, May 2014 .    Read the Full Article Now Available Here
Voice Coil  Test Bench
Eminence N314X TeXtreme Compression Driver
By  Vance Dickason
This Test Bench focuses on a very special new Eminence product, the new N314X 1.4" compression driver. The N314X is the first compression driver that uses TeXtreme composite for a diaphragm. TeXtreme thin-ply carbon is a novel type of material that is used in applications that require a high degree of stiffness performance in combination with ultralight weight. Designed for use with 1.4" throat horns, the N314X compression driver has a 35.6 mm (1.4") throat diameter driven by a 3" diameter voice coil wound with round copper-clad aluminum wire (CCAW) on a non-conducting polyimide former driving the TeXtreme diaphragm and the PEN surround. The N314X also incorporates a three-slot annular phase plug and an acoustically damped black die-cast aluminum cover with heatsink fins. Other features include a FEA-optimized neodymium magnet motor structure, a continuous power handling of 300 W with a 75 W (AES) power handling rating, a 800 Hz recommended crossover frequency (with a minimum 12 dB/octave high-pass network), and 1 W/1 m 110.5 dB sensitivity (average output across the operational frequency range). This article was originally published in Voice Coil, May 2020 .    Read the Full Article Now Available Here

AX August 2020: Digital Login
Audio Product Design | DIY Audio Projects | Audio Electronics | Audio Show Reports | Interviews | And More 

Don't Have a Subscription?
VC August 2020: Digital Login
Industry News & Developments | Products & Services | Test Bench | Acoustic Patents | Industry Watch | And More