Voice Coil Patent Review: Controlled Passive Radiator

James Croft has fun reviewing a Controlled Passive Radiator patent awarded to inventor Tony Doy, on behalf of Sonos (Santa Barbara, CA.) The patent details multiple techniques to control a passive radiator, including a device buffering successive samples of audio content and predictive techniques on active designs. With this extensive review, Voice Coil readers will gain a valuable perspective on key possible innovation areas. This article was originally published in Voice Coil, October 2018.

In this Test Bench I characterized the 12BG76-8, a high power handling 12” NBR pro sound woofer from B&C Speakers. This month’s sample submission is in the upper range of power handling in this extensive group with a continuous power handling rating of 1000 W (500 W nominal). Applications range from two and three-way PA speakers and compact two-way designs for high SPL in limited spaces. Features for the 12BG76-8 are similar to most high-performance pro sound drivers, fairly substantial. This article was originally published in Voice Coil, October 2018.

This month, I characterized the SW275BD01, a 10.75" high-end home audio subwoofer from OEM manufacturer Wavecor. This driver has a well-appointed feature set that includes a proprietary cast eight-spoke (four twin spokes) cast aluminum frame, a very stiff black mica/paper composite cone, further stiffened by a 4" convex black hard paper dust cap. Suspension is provided by a FEA optimized low-loss (high Qm) NBR surround plus dual 6” diameter black flat conex spiders (dampers). This article was originally published in Voice Coil, October 2018.

From speaker practice and theory, this article on advanced test methods for improving Active Noise Cancellation (ANC) headphone performance attempts to gain better data to draw stronger conclusions about the ANC performance and is a must-read for product developers and anyone interesting in learning how to evaluate those systems. This article was originally published in audioXpress, October 2018.

This edition of Voice Coil highlights all the 145th Audio Engineering Society (AES) International Convention events and sessions of interest for the loudspeaker industry. Mike Klasco offers a unique perspective on Soundbar Audio Signal Processing and provides an updated directory of OEM/ODM contract manufacturers in this field. James Croft reviews a new Controlled Passive Radiator patent awarded to Sonos and Vance Dickason characterizes a 10.75” high-end home audio subwoofer from Wavecor and a new 12” NBR pro sound woofer from B&C Speakers. Now available in print and digital!

Another edition of audioXpress is now available, and this is another one of those issues you don't want to miss. On our cover, we call your attention to Tom Perazella's amazing Egg Speakers, a project which we continue to detail this month. Next, Stuart Yaniger reviews the latest Phantom Power Microphones from PCB Piezotronics, we discuss advanced test methods for improving Active Noise Cancellation headphone performance, and we interview Michael Goodman, CEntrance Founder and CEO. And there's more speaker projects, and great audio theory articles. Download it now or subscribe!