Get Up Close with the Loudspeaker Experts in Voice Coil August 2019

July 24 2019, 09:15

Voice Coil August 2019 is now ready for you to download (and on the way to your mailbox if you’re a print subscriber). And this month’s edition is full of great reasons to read it from start to finish.

We start with Mike Klasco and Nora Wong’s (Menlo Scientific) report of the ALMA International Symposium & Expo (AISE) that this year took place in Orlando, FL just prior to InfoComm 2019. AISE is ALMA’s main annual event, held since the late 1960s, traditionally taking place just prior to the Consumer Electronics Show (CES). But things have changed - and boy did they change! As the article details, the Association of Loudspeaker Manufacturing & Acoustics (ALMA) International promoted another great event for the first time in June, while at the same time announcing further structural changes. Apart from the calendar changes and the widening scope of activities, ALMA International announced that the organization is also changing its name to Audio & Loudspeaker Technologies International or “ALTI.” And the association’s event will now be called ALTI Expo. To understand why, you will have to read the full report on this month’s Voice Coil.

And as tradition dictates, for this edition of Voice Coil, Nora Wong prepared a completely updated directory of Global Voice Coil Manufacturers 2019. From US voice coil winders to the far more numerous Asian-based suppliers, not forgetting the European and Indian counterparts. It is a valuable list of companies and contacts that no loudspeaker professional can do without.

And of course, this edition of Voice Coil includes another valued patent review article by James Croft (Croft Acoustical). This month, he focuses on an Externally Coupled Loudspeaker System for a Vehicle, a patent recently granted to Markus Christoph and Andreas Pfeffer Andreas, on behalf of Harman Becker Automotive Systems GmbH (Karlsbad, Germany). The patent describes a loudspeaker system arranged in a baffle inside a vehicle, configured to radiate an acoustical signal to the passenger compartment using an active noise control system, where a microphone is acoustically coupled to the loudspeaker via a secondary path, and the loudspeaker is electrically coupled to the microphone via an active noise control filter.
Sounds too generic? And you would be right to think it is.

And that’s precisely why Croft decided to combine this review with another patent granted also this year to Takashi Kinoshita (Yokohama-shi, JP) and Ben John Feng (Sudbury, MA) on behalf of Bose, describing an "Externally Ducted Vehicle Loudspeaker." The Bose invention describes various implementations of “vehicle loudspeakers and related vehicle audio systems,” including the use of passive radiators. The review goes into detailing prior art and relevant awarded patents in automotive applications, all apparently trying to deal with the dilemmas of noise levels and environment control inside the vehicle.

Next up, in Test Bench, Vance Dickason characterizes one of the most anticipated drivers launched in the market this year. In fact, two of the new graphene-coated magnesium cone drivers from SEAS’s Excel Graphene range. As Dickason explains, this product line has been an ongoing project for more than two years, combining the already highly prized magnesium cone - a nearly ideal cone material that is both light and stiff but is subject to corrosion in areas of extremely high humidity - with the desirable acoustic properties of Graphene, which also works to provide corrosion protection to magnesium.

This month’s edition of Test Bench actually characterizes in detail two different woofers from the new Excel Graphene product line - the W16NX003 5.25” midbass driver; and the latest edition to the Excel Graphene line, the W18EX003 6.5” midbass driver.

And of course, Voice Coil August 2019 also includes the usual selection of important updates in its Industry Watch section, compiled by Dickason.

This edition is available for download and already in the mail for print subscribers. Subscribers can go to - - to download this issue.

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