October 2026

Loudspeaker Engineering And Sound Systems
Resisting rewriting history of JBL.
Editorial By J. Martins

  For this speaker-focused issue of audioXpress we have explored several fascinating trends in modern speaker design that are becoming far more recognized. Thomas Perazella shares his explorations and impressions to enhance the listening experience with Edgar Choueiri's BACCH spatial-audio technology and suite of processing tools. The BACCH algorithms, software, SDKs, and related IP are available for licensing from BACCH Labs, while the hardware processors and software are commercialize2d by Theoretica Applied Physics, the company founded by Edgar Choueiri. What is fascinating is that while Thomas Perazella's interest was triggered by crosstalk cancellation, the exploration of the BACCH software quickly allowed him to understand the broad benefits of enhancing loudspeaker-based spatial imaging. Not surprisingly, Edgar Choueiri summarizes his approach as "spatial audio" and the aim of its processing tools as to allow the listener "to experience spatially accurate 3D sound from a pair of stereo loudspeakers."

And from the realm of "stereophonic sound," we progress toward the concepts of "3D sound" and "Spatial Audio" even with two speakers as the source.

Gary Eickmeier's review of GertKeunen's self-published book, Stereo – Was a Nice Try: Creating and Producing Immersive Music, is a fitting follow-up. Gary Eickmeier, author of Audio Praxis: An Image Model Theory for Stereophonic Sound, has dedicated his life to exploring the concept that "stereophonic" is not binaural and should not be limited to two-channel sound. His Image Model Theory (IMT) examines spatial relationships between speakers and the room through direct and reflected sound. Gary Eickmeier found confirmation in Gert Keunen's book, which questions the future of stereo and explores immersive audio, particularly its intent and three-dimensional experience. This book serves as an important starting point. As Gary says, "This goes way beyond loudspeaker design, recording techniques, signal measurement and processing, and acoustic treatment."

This issue of audioXpress also explores advanced speaker design techniques, from modeling and simulation in early design stages to a DIY-oriented project of an active loudspeaker with acceleration control and Doppler compensation. The topic is familiar to readers due to articles by Reinhold Lutz, a recognized authority in Motional Feedback (MFB) and supplier to high-end audio brands. His experience with electronics modules offers an interesting perspective on fully integrated active loudspeaker systems that continuously measure and correct membrane motion and harmonic/intermodulation distortions. Speaker builders are encouraged to explore further.

A word to signal our historical interview this month. Mark R. Gander, a former Harman engineer, retired in December 2017 after 40 years at JBL Professional. His last position was Director of Technology. Scott Leslie, a former JBL and Harman engineer and experienced loudspeaker industry professional, originally made this lengthy interview in 2024. He envisioned a detailed conversation about Mark's professional journey and the many landmark products that helped establish JBL Professional. However, the long conversations were never transcribed, and the challenges to research and collect the necessary images caused an inevitable delay.

After an inspiring meeting at the Audio Engineering Society (AES) Show in Long Beach, CA, and conscious of JBL's 80th anniversary celebrations, I decided to pursue this project. I visited Mark's home in Topanga, where Scott's original interview took place, to go through his personal archive and gather images illustrating his career. It was also an opportunity to learn more about JBL, a company to which I have a personal connection. In the 1990s, I worked with JBL and other Harman brands and met Mark Gander. I attended the historical launch of the JBL EON series, witnessed the demise of the UREI range, and saw private buyers scoop JBL's historical studio monitor series and replacement drivers. The original interview was extensive and reflected my knowledge and learning. We resisted rewriting the history of James B. Lansing Sound, Inc., to preserve Mark's words and memories.

I enjoyed my time with Mark and will be grateful for his time and wisdom. I also acknowledge Becky Barabas and David Glaubke at Harman Northridge for their assistance in supplying materials from the JBL 80th-year anniversary exhibitions and publications.

J. Martins
Editor-in-Chief

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