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.

The use of standard filter alignments represents a foundational concept in the loudspeaker industry, with an impact nearly as significant as the invention of the electro-dynamic loudspeaker principle itself. As one of the creators of Speakerbench, a web-based speaker design tool, in collaboration with Jeff Candy, Claus Futtrup is in a unique position to discuss the evolution of enclosure designs based on this electrical filter theory, including the concept of an alignment chart.

Niron Magnetics, the company pioneering the world's first high-performance, rare earth-free permanent magnets, announced it has received $25 million in new strategic funding from Samsung Ventures, Allison Transmission, and Magna. This investment will strengthen Niron's ability to expand its production facilities, scale manufacturing capacity for exclusive customer programs, and accelerate the commercialization of Niron's Clean Earth Magnet technology.

Following the announcement that Tymphany partnered with the Fraunhofer Institute for Integrated Circuits (IIS) in Germany to provide new state-of-the-art spatial audio solutions to audio manufacturers, Tymphany now confirms that at the CES 2024 show in Las Vegas, the two companies will demonstrate new reference designs for both headphones and speakers. These demonstrations will take place at Suite #26336 of the Venetian.

With a visit to Dutch & Dutch, Jan Didden unveils the journey of this innovative speaker manufacturer from The Netherlands. This company, founded in 2014, has so far achieved remarkable success with a single product designed to break the vicious cycle of speakers and room acoustics. The Dutch & Dutch 8c is a no-compromise active speaker designed to work together with the acoustics of the listening room.

Snap One - the company that resulted from the acquisition and merger of SnapAV with Control4 and owns Triad speakers - refreshed its home theater speaker line with new materials and capabilities. An expanded family of Episode Home Theater speakers is now available, with a unified range of high-performance drivers designed to deliver cinematic sound and support the latest object-based surround sound technologies.

The SonicEdge transducer - a cutting-edge microspeaker based on a unique MEMS technology that generates sound using active ultrasound modulation - introduces a completely new class of devices that can deliver constant volume velocity across audio frequencies and beyond. The article details how to model the transducer in lumped-element and finite-element acoustic simulations and how to tailor a desired SPL response using acoustic features. As originally published in audioXpress, August 2023.

As anticipated in early August 2023, Garmin announced it has completed the acquisition of JL Audio, the privately-held US company that designs and manufactures audio solutions including speakers, amplifiers, subwoofers and other audio components for marine, aftermarket automotive, powersports, home and RV applications. The acquisition was intended to add premium audio integration solution across a broad range of Garmin markets and products.

This article discusses a patent originally claimed in 2013 on a Double Coil Speaker design, which was granted in 2017 to Friedrich Reining (Vienna, Austria), on behalf of Sound Solutions International. The abstract from the patent details an audio system comprising an electro-acoustic transducer having two stacked voice coils mechanically linked to a membrane. James Croft discusses multiple approaches in similar concepts, and notes that the current state of technology might finally create a way to explore it in commercial products. This article was originally published in Voice Coil, March 2018.

This patent, granted to MrSpeakers, the company from San Diego, CA that is now Dan Clark Audio, was granted in the same month that this review was published in Voice Coil. The patent details a headphone driver that should also be of note for the speaker industry. As Croft notes, the patent office initially rejected the claims due to prior patents, eventually accepting the inventor's arguments, in 2016. The review provides the historical context for planar magnetic transducers, and explains why this is an important patent.