Spotlight features a complete overview article, written by Robert Werner, of KLIPPEL’s QC Version 5 system for electro-acoustic devices. As the author details in this comprehensive overview, “its many new features make one of the most specialized loudspeaker-related testing systems even better. QC Version 5’s new features broaden the application range, ease handling and usability, and meet new requirements and feature requests.” Imperative reading for anyone working in the loudspeaker industry.
In Acoustic Patents, James Croft (Croft Acoustical) reviews a patent recently granted on Inverse Horn Loudspeakers, awarded to inventors Philip R. Clements; (Tempe, AZ), Boaz Shalev; (Needham, MA), James Joseph Croft, III; (Bellevue, WA) on their own behalf. The patent describes a low-frequency transducer system with a multi-compression chamber, where an inverse horn structure is employed in combination with a resonance-distortion filter chamber. The filter chamber effectively expands the effective enclosure volume at low frequencies and connected to one of the compression chambers filter parasitic resonances and distortion, allowing the system to more efficiently reproduce low frequencies while being able to use smaller diameter transducers and maintaining good system sensitivity. Compression chambers are organized for constant or continuous compression on a section-by-section basis throughout the inverse horn system.
As James Croft comments, this is the third patent granted on Atlantic Technology’s low frequency system known by the trademark name H-PAS (High Pressure Acceleration System). The primary embodiments of this system are the creation of Phil Clements, who developed a similar system in the early 1970s, disclosed in US 4,373,606. “While the system superficially appears similar to a transmission line, with a Helmholtz side chamber, the length of the “inverse-horn” waveguide is not long enough to establish a quarter wave column resonance at the fundamental tuning frequency (FB), and in actuality system FB corresponds more closely to a specialized type of Helmholtz Bass Reflex device,” the author adds.
In this month’s Test Bench, Vance Dickason characterizes a redesigned 1.4” driver from B&C Speakers and a 5.25” woofer from Tymphany. The B&C Speakers driver, DE990TN-8, is a 1.4” neodymium motor compression driver with a titanium diaphragm coupled with the ME90 horn. The second driver, from Tymphany, is a patent-pending thin profile 5.25” aluminum cone mid-woofer from the company’s GBS line of thin-profile woofers and midranges, the GBS-135F25AL02-04.
This issue also features the usual mix of updates on people, companies, and products on Industry Watch. Download the September 2016 issue now!Note: Selected past issues of Voice Coil’s Test Bench can be found online here: audioxpress.com/categories/vc-testbench
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