Essential Reading in Voice Coil September 2018 Before Heading Off to CEDIA!

August 24 2018, 12:00
The Custom Electronic Design & Installation Association (CEDIA) Expo is fast approaching and as usual, the Voice Coil September 2018 edition features all the essential information for loudspeaker industry professionals regarding this year’s Custom Electronic Design & Installation Association (CEDIA) Expo event, which is being held for the second time in San Diego, CA, at the San Diego Convention Center from September 4-8. And in Industry News & Developments our readers will find new product information from Dayton Audio and Scan-Speak.

In Acoustic Patents, James Croft (Croft Acoustical) reviews a recently published design by Ralph E. Hyde (Santa Clara, CA) for a “Dual Coil Electrodynamic Transducer with Channels for Voice Coil Cooling,” which was submitted on behalf of Harman International Industries on January 2017. The design details an important approach to solving the everlasting problems of heat generation that limits the power handling capacity and the distortion-free acoustic output capability of loudspeakers, as well as their efficiency as electroacoustical transducers. For these well-recognized limitations, the inventor proposes a multi-coil transducer with multiple approaches to improve the cooling structure, which Croft examines in detail and puts in historical and practical perspective.
For this month’s Test Bench, Vance Dickason characterizes the new Dayton Audio Epique E160CF-8 midbass driver and two new 28 mm dome tweeters also from Dayton Audio — the RST28A-4 and the RST28F-4. The first one is from the company’s new Epique high-end transducer line and Dayton Audio’s entry into the ultra-high-end driver market, competing with well-establish brands in the segment. Applications for the new 5.25” E160CF-8 include use as a midrange in a multi-way speaker or as a woofer in a two-way speaker.
The next two transducers are both new tweeters from the Dayton Reference Series. Dayton Audio’s RST28A-4 and RST28F-4 are similar tweeters that share pretty much the same platform with the primary difference being the RST28A-4 uses an 30 mm aluminum dome and the RST28F-4 has a 30 mm coated silk dome. Other features in common include a 4 Ω voice coil, a ferrite magnet motor structure, an aluminum faceplate, a tuned injection-molded rear cavity, low viscosity ferrofluid in the gap area, a phase diffuser with a protective screen, 50 W RMS power handling, replaceable diaphragms, and gold-plated terminals.
In this edition, Dickason also highlights the fact that he is now using LOUDSOFT’s new FINE R+D Analyzer with the FINE Hardware 3 192-kHz sampling rate platform. Basic features of the new analyzer include three microphone input channels with selectable 48 V Phantom power, a balanced 25 W internal amplifier, XLR balanced line out (allows using a higher powered outboard amplifier), plus a built-in power supply with a front panel on/off switch (and no wall wart!). Although the analyzer is delivered with a DPA microphone, Dickason implemented with the G.R.A.S. Sound & Vibration Type 46 BE microphone, which he already used in the established Test Bench measurements.
Finally, in this edition of Voice Coil, we honor the memory of David A. Wilson II, the founder of high-end loudspeaker manufacturer Wilson Audio, who passed away on May 26, 2018. Dickason pays homage to the life and achievements of Dave Wilson and the remarkable company the he build, together with his wife and partner Sheryl Lee, and which is now in the good hands of his successor, his son Daryl Wilson, who has also strongly contributed to the design of countless successful loudspeaker models.
The Industry Watch section of Voice Coil includes the usual mix of news and updates that are essential reading for loudspeaker industry professionals.
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