Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 3

In the third article of the four-part series, Andy Lewis continues his fascinating exploration of Back EMF Phase Relationships in Moving-Coil Loudspeakers. The author discusses what causes Back EMF to simulate inductor, capacitor, or resistor (LCR) components, and explores the concept of slip, in order to explain how and why it causes the impedance to be inductive, resistive, or capacitive, depending on frequency. This article was originally published in audioXpress, July 2018

In this edition of Test Bench, Vance Dickason characterized a different high-frequency transducer: the TPL200/H, a horn-loaded pro sound AMT from the Valencia, Spain, company Acustica Beyma. The TPL200/H is one of the Air Motion Transformers (AMT, aka AVT Air Velocity Transformer) that Beyma has developed for pro sound applications and is a Kapton horn-loaded version of the highest power handling AMT in their AMT line, rated at 120 W AES (24 W program), with a sensitivity of 104 dB 1 W/1 m. This article was originally published in Voice Coil, July 2018.

In this Test Bench, Vance Dickason looks at an interesting new high-frequency transducer: the 951PB, a 1.4” exit pro sound compression driver from Radian Audio Engineering, based in Orange, CA. The 951PB shares an almost identical feature set with the existing 950PB. Both have neodymium ring magnet motors, high temperature 101.6 mm (4”) diameter polyimide voice coil formers wound with copper-clad aluminum-edge wound ribbon wire voice coils. This article was originally published in Voice Coil, July 2018.

In this Voice Coil Spotlight, Mike Klasco writes about SoundChip, a unique solution provider for active noise cancellation product engineering. SoundChip operates not as consultants but as solution providers and collaborators, enabling product development teams to access a vertically integrated portfolio of technologies, IPs, devices, tools, and services, needed to reliably develop and produce, at scale, high-performance noise cancelling headphones. This article was originally published in Voice Coil, July 2018.

Latvia-based Sonarworks is a recording studio software development start-up specializing in acoustic calibration and DAW plug-ins. For years, the company has been working with custom studio installations and developing software solutions, based on research by audio engineer Kaspars Sprogis. Stuart Yaniger reviews this pioneering speaker calibration software for studio monitors and headphones, and also addresses the recent TrueFi solution released for the consumer market. Originally published in audioXpress, July 2018.

Originally published in audioXpress July 2018, we are now making available online the complete Audio Expo North America (AXPONA) 2018 Show Report, with all the details about the best sounding rooms and ultimate high-end gear from the Chicago, IL, show. AXPONA is one of the largest high-end audio shows in North America - and with the full potential to become the largest, thank to excellent facilities provided by the new Schaumburg Convention Center and Renaissance hotel.

The Voice Coil July 2018 edition is now available and full of great content and insights, apart from the indispensable patent reviews and Test Bench reviews. This edition focuses on Bonding, Dispensing, Coating, and Related Aspects in Speaker Production, and features a great article by Mike Klasco on the topic, as well as an updated industry directory. James Croft reviews a patent for a “Self-bias Emitter Circuit,” awarded to Turtle Beach, while Vance Dickason looks at two interesting new high-frequency transducers, from Radian Audio Engineering, and Spanish OEM manufacturer Beyma.

audioXpress July 2018 is one of those editions that we are certain our readers will read, revisit, and keep for reference again and again. Start with the Editor's notes about the search for a sound reference standard, read our review of Sonarworks Studio Monitor and Headphone Calibration Solution, Reference 4, and learn more about microphone choices. Next up, we interview the new owners of Creative Sound Solutions, a DIY-oriented company, and we follow up with the AXPONA 2018 show report. Gerhard Haas concludes his series on audio transformers for tube amplifiers, and Andy Lewis continues his fascinating exploration of Back EMF.