Patent Review: Inverse Horn Loudspeakers

This article reviews a patent originally granted to inventors Philip R. Clements; (Tempe, AZ), Boaz Shalev; (Needham, MA), and James Joseph Croft, III; (Bellevue, WA), which has now expired. 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. This was the third patent granted on Atlantic Technology’s low frequency system known by the trademark name H-PAS (High Pressure Acceleration System). This article was originally published in Voice Coil, September 2016.

The driver I received for testing in this edition of Test Bench came from Tymphany, and is a patent-pending thin profile 5.25” aluminum cone mid-woofer from the company’s GBS line of thin profile woofers and midranges. Features for the GBS-135F25AL02-04 include a four-spoke stamped steel frame with a mere 27.4 mm (1.08”) total depth. The depth is significant as the motor assembly is obviously housed inside the frame. This article was originally published in Voice Coil, September 2016.

It’s that time of the year again. September means our Speaker Focus edition is here and once again we have a powerful selection of articles, starting with a great recap from Mike Klasco on the Evolution of Compact Deep Bass Subwoofers. We follow with three great DIY articles from Ward Maas, Ken Bird, and Perry Marshall. Of course, there’s also the second part of Richard K. Mains’ techniques on how to eliminate room reflections in woofer measurements, and a great interview with David MacPherson, owner of Studio Electric. Read on!