DALI Introduces IO-12 Refined Headphones Design for a Superior Listening Experience

At the Munich High End Show in May 2023, Danish Audiophile Loudspeaker Industries (DALI) celebrated its 40th anniversary and unveiled two ground-breaking additions to its product portfolio: the EPIKORE 11 loudspeaker and the IO-12 headphones. Both products incorporate DALI's patented Soft Magnetic Compound (SMC) technology. Five months later, the IO-12 wireless headphones with its 50mm custom dynamic drivers are available to consumers offering Active Noise Cancellation, 35-hour battery, aptX Adaptive Bluetooth and USB-C/3.5mm wired connections.

This Test Bench addresses Purifi Audio’s PTT4.0X04-NFA-01 4” midbass, which is very similar to the PTT6.5X reviewed in Voice Coil July 2021, and includes the same constant Sd surround and low magnetic hysteresis motor design. The distinct cone assembly for this driver consists of a flat profile paper cone made with a proprietary fiber mix, a concave dust cap that covers about 90% of the cone surface, plus the addition of a V-shaped edge reinforcing ring glued around the outside rim of the back side of the cone. Compliance is provided by a unique NBR surround, which as in the PTT6.5X surround, deserves to be explored, motivating Vance to discuss it with Purifi’s co-founder Lars Risbo.

In this article for Voice Coil, the two co-founders of Purifi Audio share some details about the company's unique research with loudspeakers, and reveal their findings in looking for the roots of speaker nonlinearities and distortion mechanisms. A research effort that the authors believe deserves consideration from the industry, as a new set of standard parameters that should be included in datasheets. This article was originally published in Voice Coil, August 2021.

Purifi Audio, the Danish company founded by Bruno Putzeys, Lars Risbo, and Peter Lyngdorf together with a remarkable engineering team, promises Class D amplifiers with record-breaking performance (as well as speakers). Now, Bruno Putzeys made available a detailed report of his investigation on hysteresis distortion, which motivated the development of the company's products. As Putzeys describes, hysteresis in the ferromagnetic material of the amplifier output filter coil is what causes "a recognizable grainy texture in the sound."

audioXpress' Technical Editor Jan Didden met with Bruno Putzeys and Lars Risbo, the founders of Purifi Audio, the new Danish company that the entire audio industry is talking about. The Netherlands Audio Engineering Society (AES) section invited the duo for a technical update on their plans, and they gracefully agreed to a presentation on June 13 at the Royal Conservatory of Music in The Hague, which Didden attended and reports here. This article was originally published in audioXpress, September 2019.

Anyone who is serious about designing a loudspeaker using dynamic drivers is either familiar with, or has used, Thiele/Small parameters, generally accepted as ways to predict driver behavior in different enclosures. But there are other measurement methods we can use to determine and quantify nonlinearities: the DUMAX system, produced by DLC Design, and the Klippel Analyzer System by Klippel GmbH. This article was originally published in audioXpress, March 2003.