Stealth Magnet Technology

In the acoustic design of planar magnetic headphones, the magnet array is the core component that drives the diaphragm — yet it also stands as the single greatest obstacle in the path of the sound waves it produces. In conventional planar magnetic designs, the individual magnet bars have a square or rectangular cross-section, and as sound waves pass through them, they generate significant diffraction and reflection, causing distortion and a loss of detail. HIFIMAN's Stealth Magnet technology was developed specifically to resolve this conflict.

At the heart of the technology is a redesign of the magnet's geometry. According to HIFIMAN's patent filings, the Stealth Magnet has a flat base with side walls that taper progressively toward the top, producing a cross-section roughly resembling a trapezoid with rounded corners. This shape allows sound waves to diffract around the magnet array, wrap past the magnets, and recombine into a more coherent wavefront behind them. Dr. Fang Bian, founder and CEO of HIFIMAN, sums up the idea as "making the magnets invisible to sound waves."

Acoustically, Stealth Magnet technology employs an asymmetrical, double-sided magnetic circuit — one that gradually varies the magnet gap and cross-sectional profile on both sides of the diaphragm. Compared with conventional symmetrical magnetic circuits, it markedly increases the acoustic transmittance of the diaphragm's output, allowing sound waves to pass through the magnet array more completely and with less obstruction. Air turbulence and reflections within the gaps between magnets are minimized, and both diffraction and wave disturbance are substantially reduced, lowering total harmonic distortion (THD) and overall distortion. Reviewers have reported that the audible result is a more relaxed presentation, less clearly defined soundstage boundaries, and a sense of space that approaches a live performance.

Stealth Magnet technology made its debut in the flagship SUSVARA and has since trickled down to a range of models, including the Arya, ANANDA, DEVA Pro and HE400se (in their Stealth Magnet versions). From a flagship priced at close to RMB 40,000 to entry-level planar magnetic headphones costing well under RMB 1,000, the spread of this technology is bringing the purity of "acoustically transparent" magnets to a far wider audience.