Designing and Manufacturing Loudspeakers? Voice Coil May 2019 is Now Available!

April 26 2019, 09:30
Voice Coil May 2019 features an overview of Asian speaker manufacturing outside of China, with a detail portrait country by country. Mike Klasco reports on Loudspeaker Enclosure Materials, focusing on new and improved material alternatives. James Croft reviews a new patented design from Harman to improve reproduction in boundary-coupled systems, and in Test Bench, Vance Dickason characterizes two new 1” compression drivers, one from Celestion, and another from SB Audience, a new brand from SB Acoustics targeting pro audio applications. All this and the usual Industry Watch updates, now ready to download!

In this edition, Voice Coil spotlights the Asian speaker manufacturing outside of China. In a valuable insight report, Mike Klasco (Menlo Scientific, Ltd.) details the current loudspeaker manufacturing challenges and opportunities in the Asian region, offering an overview of the players in each country and how they have evolved over the last decades. As Klasco writes, the Silk Road of loudspeaker manufacturing has evolved over the years. "Back in the 1960s and 1970s, the Asian speaker industry consisted primarily of Japanese companies with giants such as Onkyo, Pioneer, Foster, Panasonic (Matsushita), and a few long-forgotten others, variously providing branded, OEM and ODM services. In the early 1960s, “cottage industries” were common in Japan where workers built sub-assemblies at home (and were paid by the piece) and carried their work over to the “factory” on weekends where they worked on the production lines to do the final assembly. This “JVC” format evolved into a large assembly campus surrounded by just-in-time vendors supplying component parts (e.g., voice coils, frames, cones, and more)." You really want to read the rest...

In this May 2019 edition, Klasco also offers the second part of his report on Loudspeaker Enclosure Materials, focusing on new and improved materials alternatives. The report details how new materials offer a valuable alternative to injection-molded thin-wall lightweight plastics, without the expense of sonic integrity. While ABS, HIPS, PC, Poly, and other plain materials dominate today’s speaker enclosure products, there is a new world to be explored from companies such as Eastman Chemical and its TREVA cellulose-based engineering bioplastic, INEOS Styrolution's Stylight thermoplastic formable composites, Industrial Dielectric's (IDI) bulk-molded compound (BMC) and Structural Thermoset Composites (STC), A.Schulman's product line of BMC and SMC thermosets, Globe Plastics BMC-molded solutions, Covestro's Maezio continuous fiber-reinforced thermoplastic composite (CFRTP) and many other advanced material suppliers.

In this month's Acoustic Patents column, James Croft (Croft Acoustical) reviews a brand new Multiple Path Acoustic Wall Coupling for Surface-Mounted Speakers approach, awarded to Paul Wayne Peace Jr. (Viejo, CA) and Derrick Rodgers (Altadena, CA), on behalf of Harman International Industries. The patent describes a surface-mounted loudspeaker design that mitigates the interference between direct low-frequency (LF) energy and reflected LF energy by breaking the LF energy from an LF driver into multiple paths using one or more of waveguides, driver load plates, and enclosure ports to diffuse the reflected energy and minimize frequency response errors. Croft dives deep into this design approach and puts into context with prior art and a complete evaluation of its merits, which could effectively offer a useful way to improve reproduction in boundary-coupled systems.

In Test Bench, Vance Dickason characterizes two new 1” compression drivers, the CDX1-1732 from Celestion, and the Russo 44CD-K, from SB Audience, a new brand from SB Acoustics targeting pro audio applications.

The Celestion CDX1-1732 joins the CDX line of neodymium motor compression drivers, now totaling 12 models. Designed for use with 1" throat horns, the CDX1-1732 is driven by a 44 mm (1.75") diameter voice coil wound with edgewound copper-clad aluminum wire on a high-temperature fiberglass non-conducting former driving a single piece polyimide diaphragm and surround. The diaphragm is fixed using Celestion’s Sound Castle soft clamping assembly methodology, which purports to reduce the stress associated with holding the diaphragm in place, decreasing distortion and increasing reliability. For this Test Bench, Celestion supplied its 1” H1-7050 “No Bell” elastomer (plastic rubber) damped cast aluminum 70° × 50° exponential flare horn.

Recently, Sinar Baja has announced a new product category organization for its various brands. SB Acoustics will continue to be its hi-fi driver product range, including Satori, while SB Audience is now its pro sound product line, and SB Automotive is now the brand common to its car audio product line. For this Test Bench, the company sent the SB Audience 44CD-K, a new FEA-optimized ferrite compression driver from the Russo model line (Russo being the “high performance at an attractive price” line), along with its ABS-250 90° × 90° exponential horn. SB Audience also has two other product lines that include Nero, the “highest performance” line, and Bianco, the “good performance at the lowest cost” product line. The SB Audience 44CD-K has a 1" throat exit designed for use the 1" horns, and includes a 44 mm (1.75”) diameter voice coil wound with round copper wire on a high-temperature Kapton non-conducting former, driving a single piece polyimide diaphragm and surround.

All this and the usual compilation of important updates for the loudspeaker industry in Industry Watch, now available for download and already in the mail for print subscribers. Subscribers can go to - - to download this issue.

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