Voice Coil April 2024 is now available in print and digital with another issue full of valuable knowledge and innovation. This issue kicks-off with an excellent thought piece by loudspeaker industry veteran Tom James, on speaker measurements and the variables of SPL Graph Data. "Let's Get Back to a Level Playing Field" he proposes, as he explores the impact of ignoring or intentionally manipulating the rules established in the "Scales and Sizes for Plotting Frequency Characteristics and Polar Diagrams," IEC-602632 standard, originally from 1982 and updated in 2020. An insightful perspective that calls for awareness.Also in Industry News & Developments, Mike Klasco and Salvador Magdaleno-Adame discuss the recent investments received by Niron Magnetics and how this is impacting the company's roadmap for the much awaited rare-earth-free magnets that Iron Nitride represents.
And we go straight to this issue's scheduled topic - wire and cable - starting with a valuable tutorial on speaker lead-out flex wire by Mike Klasco. In his piece, titled "The Secret Life of Loudspeaker Flex Wire," he revisits the fundamentals of speaker lead-out wire, from the trailing ends of the voice coil winding to speaker terminals. Another great article where Klasco shares decades of knowledge and production experience, and details the requirements for woofers, midranges, full-range drivers, and tweeters. 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.
Continuing this month's focus, Mike Klasco and Nora Wong compiled an updated directory or Cable and Connector Vendors for speaker applications, providing a sampling of some of companies and brands to keep in mind. These include lead-out flex wire vendors, but also suppliers of connectors and cables for the speaker enclosure and interconnects.
Next, James Croft (Croft Acoustical) presents us with another masterpiece analysis of loudspeaker-related knowledge. In his Acoustic Patents column, he explores a patent awarded to Shure Acquisition Holdings, listing Brent Robert Shumard and Thomas Andrew Satrom as inventors. The title of the patent is "Audio Devices Having Low-Frequency Extension Filter" and its abstract details a filter that may increase and extend the bass frequency response of a speaker of an audio device, including ways to simulate the acoustic effects of a much larger rear cavity, and acoustic pathways, such as quarter wavelength tubes.
Having previously explored similar patents with corresponding intents, James Croft awards us with another delightful exploration of prior art, quoting some unique and bizarre inventions, but also some essential innovations that have contributed to better low-frequency architectures. As always, these are areas that have progressed tremendously with the availability of modern simulation tools, and the interesting Shure patent reflects that progress.
And for this month's serving of Test Bench, Vance Dickason explores another exciting driver from newcomer Neotera, and its UF 295 CBS Ultra-Thin 10" Subwoofer. This new 10" subwoofer is primarily intended for high-quality applications in home audio, or automotive systems, but the potential of thin-profile drivers is always intriguing. The Neotera Ultraflat UF 295 CBS is the second transducer from Neotera characterized by Voice Coil, following the UF 295 FAS dipole woofer, featured in the November 2023 issue. The level of innovation from this new Swedish/Italian company founded in 2019 shows that the company is determined to challenge conventional approaches.
The UF 295 CBS impresses immediately with its single piece black anodized concave cone assembly suspended by two large rubber surrounds, one on each side, not using a spider for compliance. The rear surround is attached to a large secondary black anodized aluminum assembly that is glued to the rear cone surface, with a series of air vents providing both thermal convection cooling and equalizing venting as the airspace volume changes. The cone is driven at its perimeter by a large aluminum voice coil and a unique motor structure of 72 neodymium bar magnets, covered by no less than 10 international patents.
The second driver discussed in Test Bench is equally intriguing and exciting, being the SEAS W16NX005 5.25" Metamodal TPCD Midbass Woofer. Part of the SEAS high-end Excel line of transducers, the W16NX005 is the first commercial product available that combines the latest Composite Sound metamodal TPCD diaphragm technology with the typical SEAS high-performance Excel woofer motor design. The TPCD metamodal technology and engineering methodology has been discussed in a contributed article by Martin Turesson, head of Composite Sound, in the February 2022 issue of Voice Coil magazine, and its benefits for controlling resonant break up modes are obvious and have been demonstrated in different sizes of diaphragms. SEAS participated in the early stages of the TPCD metamodal process, and as a result has recently released the first two TPCD metamodal drivers in the industry, including the new SEAS Excel T29X001 tweeter featured in the March 2024 issue of Voice Coil.
The subject of this Test Bench, the SEAS Excel W16NX005 midbass woofer includes a proprietary six-spoke cast-aluminum frame supporting a metamodal diaphragm and 2" convex dustcap, along with an optimized NBR surround and black cloth flat profile spider for compliance. The TPCD-based cone assembly is driven by a 39mm (1.53") diameter two-layer voice coil, powered by an FEA-optimized motor structure that incorporates a ceramic magnet and a set of dual shorting rings above and below the gap area.
And to close this issue, there's a generous dose of industry updates, starting with the now confirmed dates for the 2024 Loudspeaker Sourcing Show, which will take place October 16–18, 2024 at the Nansha Grand Hotel in Nansha (Guangzhou), South China. This is the return of the only trade show specifically organized for the loudspeaker industry and exhibiting loudspeaker component manufacturers at the OEM/ODM level. Further updates highlight news from Klippel, MAG Audio, the latest new products introduced by Beyma, and the return of the Truvox brand by Celestion.
And take note that Vance Dickason will be attending AXPONA 2024, to promote the 8th Edition of his Loudspeaker Design Cookbook in collaboration with Saturday Audio. Vance Dickason will be at the show to chat about loudspeaker design and sign copies of his new book.
Also of note, is the return of the ALTI Association to Munich, May 9–12, 2024, as part of the High End and the International Parts Supply (IPS) shows. The first two days are B2B only, and the second two days are open to the public.
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