The August 2016 issue of Voice Coil is now available online and in print. This month the Spotlight focus is on voice coil technology and production and, once again, Mike Klasco and Steve Tatarunis provide an extensive review of all the methods and materials used in bobbins, voice coil wire/winding, collar, and lead-out wires. If you want to learn about the implications of wire gauge, the voice coil winding length, the type of the wire conductors (including materials and cross-sectional shape, fabrication techniques and many other parameters) when designing the voice coil, you need to read this article. The authors also discuss thermal considerations, adhesive bonds and coatings, magnet wire insulations and wire conductor materials, and more.This is complemented by the Voice Coil Manufacturers directory, also featured in this issue.
In Acoustic Patents, James Croft (Croft Acoustical), reviews an “Orthogonal Ergonomic Speaker” independently submitted in 2013 and recently awarded to Jack Nilsson (Canton, OH), describing a system and method for an audio system with two or more speakers, drivers, sources, and the like. As the patent describes, this would be an audio system including a first speaker that reproduces sounds in a first frequency range and a second speaker that reproduces sounds in second frequency range. A crossover frequency is formed between the first frequency range and the second frequency range. The first speaker and the second speaker are physically separated by more than one wavelength of the crossover frequency and the first speaker is arranged horizontal with respect to the second speaker. As James Croft comments, the patent is interesting in its purposeful application of breaking currently established rules and may be useful in certain applications or environments.
In this August 2016 edition, Vance Dickason characterizes two transducers from Italian Pro Sound OEM manufacturer B&C Speakers. This Test Bench is dedicated to the DE1090TN, a 1.4” neodymium motor compression driver with a titanium diaphragm, coupled with B&C Speakers’ ME90 80° × 60° constant directivity horn. The second driver is the 21DS115, a 21” high power handling woofer using a neodymium motor. B&C Speakers’ new DE1090TN is the highest power handling model (120 W) in the line, now numbering 14 models (seven ferrite motor compression drivers and seven neodymium motor compression drivers). The DE1090TN has a 36 mm (1.4”) throat diameter. It is driven by a titanium diaphragm with a 100 mm (4”) diameter voice coil wound with copper-clad aluminum wire (CCAW). Other features include a neodymium ring magnet motor structure, nominal 120 W rated power handling (240 W continuous), an injection-molded aluminum black heatsink, and color-coded chrome push terminals. The horn supplied with the DE1090TN is B&C Speakers’ 1.4” throat 80° H × 60° V constant directivity cast-aluminum ME90 horn with a 0.9 kHz cutoff frequency.
B&C’s new 21DS115-8 driver is designated as a high power handling 21” woofer/subwoofer, rated at 1,700 WRMS, with a continuous power handling rated at 3,400 WRMS. The 21DS115-8 weighs in at a modest (for a 21” woofer!) 32.8 lb. The 21DS115-8’s feature set includes a proprietary 12-spoke cast-aluminum frame (six dual spokes) that has six 55 mm × 6 mm vents below the spider mounting shelf, with additional cooling provided by eight 8 mm diameter peripheral vents and a 40 mm diameter pole vent with a flared exhaust.
The cone assembly consists of a 21” curvilinear pulp paper cone and a large 7.5” diameter paper dust cap, both coated with a TWP waterproof coating (both sides on the cone). Suspension is provided by a three-roll M-shaped coated (sealed) cloth surround in conjunction with two 7” diameter flat silicone-treated cloth spiders.
As usual, this issue also features the usual mix of Industry News & Developments and Vance Dickason’s notes on companies and products on Industry Watch. Download the August 2016 issue now!Note: Past issues of Voice Coil’s Test Bench can be found online here: audioxpress.com/categories/vc-testbench
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