Patent Review: Loudspeaker Apparatus

This article reviews a patent awarded to Teppei Yamada, on behalf of Zorzo Co., Ltd. (Tokyo, Japan), describing an original design of a low-frequency enclosure system incorporating multiple woofers inter-coupled in a manner similar to what is known as an isobaric or compound woofer enclosure. James Croft reviews other approaches to the concept, starting in 1954 with a patent granted to Harry F. Olson on a dual, compound woofer system and later "reinvented" and popularized by Linn Corp., in 1975. In the new patent, the inventor uses an enclosure with as many as 12 woofers, all seriously coupled through individual air chambers

In this article, James Croft reviews a generic “Loudspeaker” concept patent, granted to Teppei Yamada, of Tokyo, Japan, on behalf of Zorzo Co., Ltd. and which describes a somewhat surprising concept of a loudspeaker that includes a hermetically sealed enclosure, with a driver outside of an enclosure and a second driver inside, with a pipe communicating between the two drivers. The second driver is configured to output a signal of opposite phase to that of the first driver. This article was originally published in Voice Coil, October 2016.

Voice Coil April 2019 is now available. In this edition, Mike Klasco discusses Microspeakers and the trends in one of the hottest loudspeaker market segments. This is followed by an up-to-date Directory on Microspeaker vendors. James Croft reviews a patent for an intriguing low-frequency enclosure system incorporating an isobaric or compound woofer enclosure. And for this month's Test Bench, Vance Dickason characterizes the SEAS L26ROY and the B&C Speakers 14NA100-8 pro sound woofer.