Patent Review: Extended Duct with Damping for Improved Speaker Performance

This article reviews a patent granted to Apple, describing an electronic audio device including an enclosure having an acoustic output opening and a speaker positioned within the enclosure, as implemented in the company’s range of iMac desktop computers. The speaker and the acoustic output opening are acoustically coupled by an acoustic output pathway and damping chamber. Apple’s patent cites the Matsushita patent as prior art, but this is a more developed concept. This article was originally published in Voice Coil, December 2015.

audioXpress December 2015 included another great Practical Test & Measurement article on “Testing Audio ADCs and DACs,” written by David Mathew from Audio Precision. As he explains, the articles discuses methods used to procure high-quality results by correctly evaluating the critical AD and DA stages, with conventional and more evolved measurements used in audio tests. The article also includes an interesting side-text detailing how Audio Precision found an ideal test case for the APx555 analyzer. Full article now available online.

Prepare for CES 2016 with the Voice Coil December 2015 issue, now available. In this issue, read how the Test Bench column has evolved, learn more about VocalZoom’s Laser Microphone, check the Microphone Capsule supplier directory and read about another audio patent granted to Apple. Learn more about two pro sound drivers as Test Bench focuses on the CF0617M 6.5” midrange driver from Celestion, and the 18iD woofer from Eighteen Sound.

It’s not that we’re saving the best for last, but audioXpress December 2015 includes some great articles on all the most current and interesting topics for the audio industry. There’s Auro-3D, two great reviews of measurement solutions, and lots of great DIY projects. And for those designing new audio products, there’s even an introduction to Audio Network Development.