Voice Coil January 2019 is now available and this edition starts with a preview of the Winter NAMM Show, in Anaheim, CA, where the magazine will be handed out. Vance Dickason highlights all the changes for this show, which is now the largest pro audio event since the two new halls opened in the expanded Anaheim Convention Center in 2018. Vance Dickason lists all events and conferences that no loudspeaker professional will want to miss.And for this month's edition, Mike Klasco and Nora Wong have compiled a special Focus article on New Materials for Earphones and Headphones. For those looking to differentiate their new products, the two Menlo Scientific consultants provide a unique and valuable perspective on all the possibilities and designs for drivers, materials for assemblies and enclosures, choices for headbands and ear cushions, signal processing, and even cables.
And because headphone projects are highly dependent on finding the right suppliers and vendors, Wong provides a valuable listing of Earphone and Headphone Manufacturers for 2019. In this updated directory, she compiled an updated list of many of the leading OEM/ODM headphone and earphone factories that only someone with deep knowledge and extensive experience in actual production would be able to provide.
And to complement the Earphone and Headphone Focus in this edition of Voice Coil, Wong also provides a schedule of headphone-centric events that professionals need to consider for its 2019 calendar.
In this month's Acoustic Patents article, James Croft (Croft Acoustical) looks closely at a brand new patent of a multilayer voice coil plate and a flat speaker including the same type of multilayer voice coil plate, recently granted to three inventors from South Korea, on behalf of ICUBES Co., Ltd., Gyeongi-do, Korea. Detailing multiple configurations of this interesting concept, including a flat speaker with a vibration plate vertically coupled to an upper edge of the multilayer voice coil plate, and configured to vibrate in a direction parallel to that same multilayer voice coil plate, this patent offers an interesting take on the quest for the realization of a high-performance, one way, full-range electrodynamic transducer. As Croft probes, the novelty of the new device is centered on the voice coil former structure coupled to the diaphragm, offering an interesting new approach, the full description of which is not fully disclosed in the patent.
For this first Test Bench of 2019, Vance Dickason characterizes two new interesting drivers. First is the 475PB, a 1" compression driver from Radian Audio Engineering, which is the second ferrite motor compression driver from the brand to be featured in Test Bench, following the 745PB, covered in the December 2018 issue. The 475PB has a similar set of features as Radian’s 745PB and includes a 1” throat diameter, a 134 mm × 19 mm ferrite magnet motor, a high-temperature 44.5 mm (1.7”) diameter polyimide voice coil former wound with copper-clad aluminum edge-wound ribbon wire voice coil, 50 W AES power handling above 800 Hz (100 W program power handing), a self-aligning field-replaceable diaphragm assembly, a copper shorting ring located in the gap area, and the most important feature — a proprietary processed and hardened aerospace-grade aluminum alloy diaphragm over a three-slit phase plug. This compression driver is measured using an Eminence H 290B 90×40 ABS exponential horn, also recommended by the Californian manufacturer.
The second driver is the SD28, a 1” soft dome tweeter from Eminence, which is an unusual driver for the US-based manufacturer, better known for its pro audio and guitar amplifier drivers. As Dickason notes, while the SD28 is listed in the Super tweeter category on the Eminence website, the suggested applications are for “car audio, ATV, RV, or any other application where space is limited.” The SD28 1” silk dome, provided without a mounting flange, features a 4 Ω impedance for a 92.5 dB sensitivity, with a response out to 20 kHz, and a self-shielding neodymium motor.
Finally, in Industry Watch, this edition of Voice Coil details the life and remarkable career of loudspeaker engineer Edgar Villchur, also recently inducted into the Consumer Technology Hall of Fame. Dickason also provides an advanced look at the new series of ribbon coaxial drivers from Radian Audio Engineering. It is a design the company has produced for many years, but has been now expanded with a series of new high-performance models, apt for prosumer applications where SPL requirements are not as high as in live sound, but sound quality is a priority. These new coaxial transducers from Radian use a unique (patent pending) circular ribbon (orthodynamic) neodymium design in 6.5”, 8”, 10”, and 12” iterations with ferrite magnet woofers and cast aluminum octagonal frames.All this and much more, not to be missed in Voice Coil January 2019. This edition is available for download and already on the mail for print subscribers. Subscribers can just go to - www.gotomyvcoil.com - to download this issue.
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