Patent Review: Radial Acoustic Speaker

In this article, James Croft discusses a patent granted to Curtis Graber (Woodburn, IN) that describes a radial acoustic speaker assembly including a transducer and a plurality of segmented spiral horns acoustically coupled to the transducer, each with its acoustical path. This new patent by prolific audio inventor, Curtis Graber, uses a new multi-spiral waveguide structure driven by a single transducer and has clear advantages over prior art. This article was originally published in Voice Coil, May 2018.

In this article, Andy Lewis explores the generation of Back EMF in the region of a loudspeaker’s resonance. He also demonstrates a method for calculating the position of the moving assembly (or “cone”) relative to input signal, using complex impedance measurements. This article - part of a four part series - was originally published in audioXpress, May 2018

In this edition of Tea Bench, Vance Dickason characterizes another compression driver from Italian OEM manufacturer B&C Speakers. The DE360-8 is the latest addition to the company's extensive 18 model ferrite and neodymium motor 1” exit compression driver range. B&C Speakers supplied the ME20 horn for use with the DE360-8, which has a 90° × 60° coverage pattern. This article was originally published in Voice Coil, May 2018.

ARTA Audio Measurement and Analysis Software, recently updated to version 1.9.1, has been on the market since February 2006, and has been evolving and improving for the last 12 years. Produced by ARTALABS (www.artalabs.hr) located in Croatia, this Fast Fourier Transform (FFT) software analyzer is probably the gold standard for cost-effective measurement software packages ($98 for a single user license, and $185 a for multiple user license). This article was originally published in Voice Coil, May 2018.

In this May 2018 edition, learn about the loudspeaker-related sessions that will take place at the upcoming 144th Audio Engineering Society (AES) International Convention in Milan. Vance Dickason also writes about ARTA Audio Measurement and Analysis Software, and for this month's Test Bench, he characterizes two new 1” exit pro sound compression drivers, the CDX1-1742 from Celestion, and the DE360-8 from B&C Speakers. In Acoustic Patents, James Croft discusses an interesting Radial Acoustic Speaker design patented by prolific audio inventor Curtis Graber. Download your copy now.

The May edition of audioXpress continues to be a favorite among tube and audio electronics aficionados. For this Glass Audio Special issue, Menno van der Veen, details his fifth 300B-SE amplifier, Patrick Brunner discusses DIY Tube Amp Heat Management, and Gerhard Haas shares what he knows about output transformers for tube amplifiers. We interviewed Jason Stoddard, the heart and mind of Schiit Audio, and Richard Honeycutt compares Tubes, FET, and BJT circuits. Also in this edition, Andy Lewis looks at Back EMF in loudspeakers, and Ron Tipton finds a way to measure the high-frequency content of Master Quality Authenticated (MQA) recordings. Download your May issue now.