Voice Coil Focus: New Materials and Technologies for Voice Coils

In this article Mike Klasco shares his extensive knowledge about voice coils, and how this critical part of loudspeaker technology has evolved - the result of decades of walking factory floors all over the world . As noted in his introduction, "Winding some wire into a coil should be simple enough and after a century of loudspeaker manufacturing, there shouldn’t be any new surprises. But voice coil materials, process control, and topology continue to evolve and here we discuss half a dozen noteworthy new tricks."

Mike Klasco writes about Niron Magnetics' first commercial pilot plant in Minnesota. The opening of this 70,000 square-foot Minneapolis facility took place in October 2024 and is a key milestone in Niron Magnetics's path to scaled production of its Clean Earth Magnet technology and the company’s ability to bridge the acute supply and demand gap for permanent magnets. A significant step forward in the company's mission to produce sustainable, rare-earth-free permanent magnets.

If we have a vehicle we value, at one point we have the car sent over to the shop for service. The same thinking applies to golden ears, from product development teams getting the product’s tonal balance DNA sonic signature, as well as chasing down buzzes and resonances. Cleaning out your ears is a sensible procedure before critical listening. This article explores self-assessment tailored to the user’s sound profile, hearing enhancement solutions, and newly available solutions for ear hygiene and visual ear care tools, such as the Bebird EarVision package.

This article explores a fascinating topic that is recurrent in the loudspeaker industry: diamond coatings. As speaker designers look to refine their products' sound quality through diaphragm treatments, there are benefits to be explored from diamond coatings, or more specifically diamond-like-coatings (DLC), which is a process that matured over the last half-century. The industry has now reached a stage where this technology becomes available and viable, particularly for microspeakers.

This valuable tutorial on speaker lead-out flex wire by Mike Klasco revisits the fundamentals, from the trailing ends of the voice coil winding to speaker terminals. How to avoid flex wire whipping, fracturing of lead-out conductors, thermal issues, and corrosion of the solder joints. What types of flex wire and wire gauges are available, what are the advantages of textile fibers and wire testing, are some of the topics addressed. This article was originally published in Voice Coil, April 2024.

All the speaker design techniques to achieve more bass, challenging Hofmann's Iron Law. The same bass in a smaller enclosure? Deeper or louder bass for the same enclosure back volume? Higher efficiency for a given alignment? A cleaner lower distortion bass? Learn about the companies, products, and technologies that make all this possible. This article was originally published in Voice Coil, November 2023.

Back in 2020, Barry Vogel, the director of the Audio & Loudspeaker Technologies International (ALTI) Association called me excitedly about Niron Magnetics and about a new magnet material developed from research at the University of Minnesota. Iron Nitride (FeN) was perhaps the biggest news in magnets in 40 years. Composed of common elements — Iron and Nitrogen - the potential of permanent magnets from Niron could be a breakthrough and a game-changer for the audio industry.

This is the last issue of Voice Coil for 2023, which includes a combination of valuable industry resources and expert knowledge for loudspeaker engineers. Mike Klasco and Nora Wong (Menlo Scientific) have compiled an updated directory of Engineering Simulation Software and Test & Measurement Hardware Vendors. And in Test Bench, Vance Dickason characterizes the latest PTT8.0X04-NAB-02 8" aluminum cone woofer from Purifi Audio.

From midbass to bass, Voice Coil November 2023 provides the lowdown on some of the loudspeaker industry's most interesting developments. James Croft explores a recently granted "Venturi expander" patent. Mike Klasco explores speaker design and signal processing techniques to achieve more bass, and Vance Dickason characterizes the Wavecor WF152BD09-04 6" midbass driver, and the UF295FAS Ultra Flat Series 10" thin-profile dipole woofer from Neotera.

This issue of Voice Coil is packed full of great knowledge for speaker professionals. The September 2023 issue features three Test Bench characterizations: the Fountek NeoCD2.0 Ribbon Tweeter, the SB Acoustics WO24TX-4 Satori midbass, and the SEAS L22ROY2 8" subwoofer. This issue also features our annual overview of Magnetic Materials for the Loudspeaker Industry. Peter Larsen (Loudsoft) concludes his FINE Circle tutorial with a passive crossover for his design. This issue of Voice Coil is now available in print, online, and in digital formats.