Another issue of the best resource for the loudspeaker industry is now available. Voice Coil March 2024 dives directly into what matters with Vance Dickason highlighting two new 2” full-range high-performance drivers from SEAS in Industry News & Developments.As scheduled for this time of the year, Voice Coil March focuses on speaker enclosures, a topic that is always relevant by itself. But this time, Nora Wong (Menlo Scientific) prepared a very special version of the 2024 Speaker Enclosure Vendor Directory, where she selected vendors that offer innovative enclosure material ideas and enclosure-related solutions. Those include an eclectic mix of materials that might be hard to find, unique, or inspire just the product differentiator you might need for one of your projects.
Read on, and don’t forget to mark these companies for current or future products: from Acry-Tech and its Duratex protective texture coating, to Alpine Advanced Materials and its revolutionary Hx5 nanofiber carbon fiber thermoplastic injection-molding resin, all the way to US Enclosure and its collection of composite wall materials purpose-engineered for loudspeaker cabinets that meet or beat the acoustic qualities of MDF, plywood, plastics, or metals at the same wall thickness.
Next up, in Acoustic Patents, James Croft serves another unique mix of knowledge and wisdom and this time re-reviews the “Speaker with Dual Diffuser” Patent invented by Mikhail Dinaburg on behalf of Dinaburg Technology. The reason to revisit this important patent, as Croft explains, has to do with the scope covered by the invention that goes beyond the integration of a passive radiator with an active driver in a bass reflex system, which was the focus of its original review.
In this second look at the patent, as he explains, he found it “interesting, entertaining, and with a view of acoustical theory that may be even more novel than the invention itself.” And that is the use of the concentric passive diaphragm radiator functioning as a dual-purpose structure. “Besides its bass reflex based, passive radiator duties, it can also, when properly optimized, operate as a “virtual” directivity controlling waveguide for the central active transducer,” he writes. Effectively, the Dinaburg invention proposes a multipurpose waveguide incorporated into the speaker’s own topology. Read on to see what James Croft concluded.
For Vance Dickason's Test Bench, we have a 6.5” woofer from Dayton Audio’s Signature Series, model SIG180-4. This series consists of five woofer models ranging from 4” to 10”, with the stated goal of being cost-effective, high-performance “audiophile” quality woofers. All drivers include single-piece concave aluminum cones, magnetically non-conducting polyimide vented voice coil formers, aluminum shorting rings, open cast-aluminum frames, plus indexed shallow transition NBR surrounds. Rated for 80W RMS power handling capacity, the Dayton Audio SIG180-4 features a FEA-optimized ferrite motor design and a 1.25” voice coil wound with round copper wire.
The next characterization for this month’s Test Bench is the Stereo Integrity TM65 mkIV High-Performance 6.5” Woofer. Stereo Integrity had its first driver explication in Voice Coil’s July 2023 Test Bench column and is an interesting new company that is aiming at both home audio and automotive/mobility applications. This month, Stereo Integrity sent Voice Coil its 6.5” midbass shallow-profile driver, which comes with a rain shield as an integrated part of the frame, meaning this device is intended for application as a door-mount woofer in a car audio system - even though the manufacturer also points for residential integration.
Features for the unique TM65 mkIV include a black anodized aluminum moderately curvilinear cone and 2.4” diameter black anodized dust cap. Suspension is provided by a tall NBR surround plus a flat 105mm diameter Nomex spider with a linear roll configuration. This is connected at the neck joint to the voice coil former, wound with round copper wire. Total depth of this driver with its proprietary frame and motor structure is a mere 58mm (2.28”).
As usual, this issue of Voice Coil closes with a dose of Industry News, where Vance Dickason highlights the recent warning from the Consumer Technology Association (CTA) for the dire consequences for American consumers if Permanent Normal Trade Relations (PNTR) status for China is revoked, as some members of US Congress propose. The key findings are summarized in the report, titled “PNTR Revocation is a Recipe for Inflation.”
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