Improving the Transfer Function of Electrodynamic Loudspeakers

This article compares motion feedback technologies applied to speakers. A recognized expert in this field, Reinhold Lutz explores how to achieve a nearly perfect electro-acoustic transfer function, including a detailed control strategy of different types of sensors. A great exploration of how a closed-loop feedback system is able to improve loudspeaker linearity.

In audioXpress January 2024, Martin Turesson explains how Thin-ply Carbon Diaphragm (TPCD) technology can be applied also to headphones, and Claus Futtrup writes about Loudspeaker Bass Reflex Alignments. Paul Marchese discusses Composite Amplifiers, Roger Tall explains how a research effort allowed ClarityCap to understand the impact of resonances in capacitors. Our own Jan Didden interviews Robert Munnig Schmidt, while audio expert Ethan Winer explores audible consequences of jitter in digital audio conversion.

Zami Schwartzman, the founder of Servobass, shares his journey into the application of Motion Feedback (MFB) methods for active subwoofers. He explores passive and active bass enhancement methods and how Servobass arrived at an optimized design using MFB techniques to achieve highly performing active subwoofers in desktop and compact sizes. A solution that is now available to be licensed by the industry. This article was originally published in audioXpress, November 2023.

Servobass is the trade name for the products and technology designed by Zami Schwartzman, and which will be making its debut at CES 2023. The company will demonstrate its Motion Feedback Desktop Subwoofers, a new shallow "under the seat" MFB car subwoofer, and its ZRS-1 class-D plate amplifier, and is open to licensing opportunities. Servobass will be at ALTI Association Hospitality Suite at CES 2023, Lido 3101B - Level 3 of the Venetian Expo and Convention Center, and at the Menlo Scientific suite.

In this article, Zami Schwartzman shares his personal journey to design and perfect his own accelerometer-based motion feedback desktop subwoofers, including plate amplifiers with MFB control, crossover and voice coil thermal protection that can be matched with any low frequency MFB driver. The proof of concept demonstrated the ability to perfectly complement popular active nearfield monitors, mitigating the effects of room reflection. This article was originally published in audioXpress, September 2022.

The September 2022 Speaker Focus issue of audioXpress discusses speaker design and testing tools and features two fascinating speaker R&D stories on the Holoplot X1 Matrix Array and Motion Feedback Desktop Subwoofers for nearfield studio application. Geoff Hill explains the latest IEC loudspeaker measurement standards, Roger Shively reports from the AES 2022 Automotive Audio conference, Christoph Sladeczek writes about Audio Objects as Platform Technology in Vehicles, and much more.