November always signals the anniversary of Voice Coil, founded as an information resource for the loudspeaker industry. As Vance Dickason reminds us, the idea for the periodical started with a conversation between himself and Ed Dell (the founder of Voice Coil and audioXpress, its sister magazine) following the publication of the third edition of the Loudspeaker Design Cookbook (now in its 7th edition and heading for the 8th) by Dell’s company. Both shared the concept of a dedicated publication for the loudspeaker industry. Dell came up with the name, Voice Coil, and as they say, the rest is history.
This edition features a Spotlight article by Aminul Md Mehedi (Senior Application Development Engineer at Carpenter Technology Corp.) on "Better Microspeakers Utilizing Hiperco Alloys" and how these solutions can contribute to smaller, thinner, and better performing drivers with higher audio output. The article details how the Carpenter-developed high-performance Hiperco 50 and Hiperco 27 soft magnetic alloys can contribute to better performing microspeakers and earphone drivers, improving "decibel (dB) density" in miniaturized consumer electronic devices. According to Mehedi, Hiperco-based drivers are more sound pressure level (SPL) dense and require less current to operate relative to a 1008 steel-based magnetic assembly.
As one of the Focus topics, Mike Klasco writes about "This Year’s Crop of Measurement Microphones." In his article, he summarizes the latest approaches the industry is using to deliver a wide assortment of measurement microphones at very different price, quality, construction, and precision levels. "A measurement microphone should have a flat frequency response over a wide frequency range, a low noise floor, and minimal variation in response — in addition to really stable characteristics that do not change with temperature, humidity, or age," Mike Klasco writes, before comparing how higher-grade ECM, condenser and MEMS microphones fare in that regard. The article also discusses how microphone correction curves and TEDS calibration are an essential part of the equation.
This article is followed by an updated directory of measurement microphones, covering every category, application, and capsule/design topology. The directory includes the less-know industrial vendors that serve the audio, noise, and acoustics measurement needs of the industry, category-specific brands, together with brands that have released a microphone than can be considered as a "measurement-able" device, and the most respected sources of scientific-level measurement equipment.
The many Voice Coil readers who look forward for Dickason's Test Bench characterizations will rejoice with two totally different drivers submitted to testing. First is the new NERO-6MRN150D pro audio midrange from SB Audience, the recently announced brand from Sinar Baja Electric (SB Acoustics); and the second driver under test is the SDx10 home audio woofer from CSS Audio.
As Dickason highlights, Indonesian-based Sinar Baja Electric in partnership with Danesian Audio of Denmark have generated an excellent reputation for the high-end home and car audio drivers that have been marketed under the SB Acoustics name. However, the company has also been producing a rather extensive lineup of pro sound OEM products, which have now been formally consolidated in the new SB Audience catalog. SB Acoustics will continue to be their hi-fi driver product range, including Satori for the high-end audio category, while SB Audience focuses on pro sound products, and SB Automotive is the company's car audio product line.
The new SB Audience 6.5” pro sound midrange from the new NERO product line, the NERO-6MRN150D, features a proprietary four-spoke-cast aluminum frame with efficient cooling, a curvilinear paper/graphite composite cone and large convex paper dust cap, flat foam surround and a 3.75” diameter elevated cloth spider with constant height waves. The motor design on the NERO-6MRN150D combines a FEA-designed neodymium ring magnet and 49.5 mm (1.95") diameter voice coil wound with round copper-clad aluminum wire (CCAW) on a non-conducting glass fiber (Til) former.
The second driver in this month's Test Bench is from Creative Sound Solutions (CSS) Audio, a company that was recently introduced to Voice Coil readers, with the LD25X tweeter, featured in the July 2020 issue. Now, CSS has sent one of its most recent XBL^2 subwoofers, the 10" SDx10, using the same dual gap motor technology licensed from inventor Dan Wiggins. Besides the XBL^2 motor, the CSS SDx10 has a well-appointed feature set that includes a proprietary cast 12-spoke (6 twin spokes) cast-aluminum frame, a very stiff coated black paper/carbon fiber blended composite cone with a convex black hard paper dust cap, NBR surround, and semi-progressive cloth spider. All this is driven 
by a 60.6 mm diameter (2.4") six-layer voice coil wound with round copper wire on a non-conducting former, with two 12 mm thick ferrite magnets sandwiched between a thick XBL-configured front plate and black-plated thick T-yoke. The braided voice coil lead wires terminate to a plastic terminal block that incorporates two color-coded chrome binding posts.
In Industry Watch, Voice Coil highlights the latest about CTA converting CES to a digital-only event for 2021, while the Audio Engineering Society and Audio & Loudspeaker Technologies International (ALTI) continue to promote different initiatives to keep the audio communities connected during the pandemic.
The November 2020 edition of Voice Coil is available for download and already in the mail for print subscribers.
Subscribers can go to - www.gotomyvcoil.com - to download this issue.
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