Voice Coil October 2020 Puts Speaker Electronics, Amps, and DSP in Focus

September 25 2020, 01:10

In line with this edition’s focus, Jin Kim and Jonathan Gerbet (Klippel GmbH) discuss the latest Nuvoton Smart Amp Platform, featuring Klippel's Controlled Sound (KCS) technology. An exciting cooperative endeavor with Nuvoton Technology, a leading provider of consumer-electronics and computer ICs from Taiwan, to release a new type of smart amplifier that is able to compensate for nonlinear speaker responses thanks to the integrated KCS technology. As a result of the project, Nuvoton developed the highly efficient mono Class-D audio amplifier devices, the NAU83G10 and the NAU83G20. The authors explain all the details you need to know.

Voice Coil October 2020 also offers a fully updated directory of speaker-focused electronics, amplifiers, and DSP vendors from all regions of the world, compiled by Mike Klasco and Nora Wong (Menlo Scientific, Ltd.). An essential reference of OEM/ODM contract manufacturers and suppliers for integrated audio products.

In this month's Acoustic Patents article, James Croft discusses a new patent titled “Planar Loudspeaker Manifold for Improved Sound Dispersion.” This is credited to inventors Michael J. Smithers (Kareela, Australia), and Garth Norman Showalter (Ozark, MO), on behalf of Dolby Laboratories. The abstract describes “an acoustic manifold for altering a sound wavefront shape from a loudspeaker” basically using a planar driver coupled to a waveguide to channel sound projected from the driver through two vertical openings. Having explored multiple patents and the history of a variety of planar magnetic transducers for Voice Coil, Croft first revisits what the planar design class  entails, placing the new patent in the so called ortho-dynamic or clamped diaphragm, “quasi-ribbon,” category. Following that characterization, Croft reviews the invention in great detail to identify its benefits and merits, which seems to be directed at pro sound applications. A great read.

And the "pièce de résistance" is undoubtedly Vance Dickason's two Test Bench articles, the first one focusing on the latest Scan-Speak Ellipticor 21WE/4542T00 midrange woofer, followed by the unique ODT29 fabric dome tweeter from Omega Audio, an OEM transducer manufacturer new to the pages of Voice Coil.

The Scan-Speak Ellipticor 21WE/4542T00 midrange woofer, part of the brand's Ellipticor family using an elliptical voice coil and magnet gap is an impressive looking driver. The 8” 21WE/4542T00 midrange woofer is the big brother to the 18WE/4542T00 and is likewise a seriously feature rich transducer. As with most all of Scan-Speak’s midwoofer/midrange frames, the 21WE/4542T00’s frame is a really nicely configured six-spoke (three double spokes) cast-aluminum frame with narrow 19-10 mm wide spokes to minimize reflections back into the black coated paper cone with an elliptical convex paper dust cap. Compliance is provided by a nitrile rubber (NBR) surround, nicely designed with a fairly shallow discontinuity where it attaches to the cone edge, plus a surface coating for enhanced damping in that critical region. Remaining compliance comes from a 4.4" diameter flat cloth spider.

The motor design for the Ellipticor 21WE/4542T00 is nearly identical to the 18WE (with nearly the same Bl) and is also an AirCirc multi-magnet design utilizing six neodymium slugs with a black emissive coating. This is also one of Scan-Speak’s patented SD motor systems and incorporates copper shorting rings (Faraday shields). The FEA designed neodymium magnet motor uses an elliptical two-layer voice coil wound with round copper wire on a titanium former. Motor parts include polished front and back plates for the neodymium magnets that incorporates a 12 mm diameter rear vent for additional cooling. As with all the transducers in the Ellipticor lineup, the 21WE has a magnetically attached aluminum trim ring that can obviously be custom anodized a variety of colors besides black.

Dickason also provided a characterization of the ODT29 fabric dome tweeter from Omega Audio, an OEM transducer manufacturer new to the pages of Voice Coil. The company, headquartered in Holon, Israel, was founded in 1978 when the founder of Omega Audio, Levi Mordechai left Morel. All of Omega Audio’s ODT line of tweeters, dome midranges are handmade in the company's facility, from dome coating to coil winding and motor assembly. The woofers are also hand assembled. All of this is done by Levi Mordechai himself, as it has been since 1978, and for this reason Omega Audio is a high-quality, small-scale manufacturer.

The features for Omega Audio’s ODT29 fabric dome tweeter include a 29 mm hand-coated fabric type diaphragm with a fairly narrow 2 mm wide surround, a felt damping ring on the top of the pole piece, ferrite motor, a plastic faceplate with a short waveguide, an aluminum voice coil former wound with copper wire, and gold-plated terminals. Read this month’s edition to see how it measured up.

And the usual section of Industry Watch closes another edition of Voice Coil discussing the latest CTA, CEDIA, AES, and ALTI association updates.

The October 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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