HiFiMAN HE-6 Planar Magnetic Headphones (Playback 37)

Stretching The Performance Envelope

Several months ago Playback reviewed HiFiMAN’s superb HE-5LE Planar Magnetic Headphone ($699), concluding that not only could its hold its own versus competitors roughly twice its price, but it could also in some respects surpass them. Obviously this meant the HE-5LE was a bargain, a product with performance so good you might think it would be pointless for HiFiMAN to try and improve upon its design. But happily for us, the folks at HiFiMAN aren’t ones to rest upon their laurels, which is why they’ve just introduced an even more impressive flagship, called the HE-6 ($1199).

HiFiMAN is a Chinese firm headed by Fang Bian, who is passionate about high-end headphone and headphone accessories. His company offers a growing range of performance-oriented full-size and in-ear headphones, a series of headphone amplifiers, several high-end personal digital music players that can handle high-res digital music files, and a range of specialty headphone accessories (e.g., high performance signal cables, adapters, etc.). In the U.S., HiFiMAN products are sold through a related distribution company called Head Direct (www.head-direct.com).

Readers will surely ask how the HE-6 is different from and/or better than the HE-5LE, and Fang Bian provides several answers. First, the HE-6 is an entirely hand-made product built with the utmost attention to detail. Second, the HE-6 features an incredibly light and thin diaphragm whose conductive surface are made of gold. The HE-6 also uses a very different magnet assembly than the HE-5LE, as I’ll explain below.

Very early-generation HE-6 prototypes sounded great, but were so inefficient that they required full-size audio amplifiers as would normally be used to power loudspeakers. Fang Bian and his team felt realized customer might not accept such a constraint, so the felt it necessary to improve the HE-6’s efficiency to a point where the headphone could be driven by conventional headphone amplifiers (albeit powerful ones). The achieve this objective, the HiFiMAN team has given the production version of the HE-6 what Fang Bian terms a “super efficient magnetic circuit.” Putting all these factors together we have a new flagship headphone that, while admittedly difficult to drive, offers even wider frequency response and lower distortion than the already excellent HE-5LE.

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About Orthodynamic Technology

The vast majority of full-size, high-end headphones on the market use traditional piston-type dynamic drivers, but the HiFiMAN HE-6 is different in that it is a so-called “orthodynamic” headphone that uses planar magnetic drivers, which are conceptually similar to the drivers used in Magnepan’s award-winning Magneplanar loudspeakers. In my earlier review of the HiFiMAN HE-5LE, which is also a planar magnetic design, I provided the following nutshell description of orthodynamic driver technology:

“In an orthodynamic driver, the diaphragm is a thin, light membrane whose entire surface is covered with a conductive coating whose ‘conductors’ are arranged in a specific pattern. The conductive driver membrane is in turn suspended near an array of magnets arranged so that, when an audio signal is fed to the driver, the entire diaphragm surface is alternately pulled toward or pushed away from the magnet array. In theory, the benefits of this approach are twofold. First, the diaphragm can be very light and responsive (lighter than the voice coil/diaphragm assembly of a traditional dynamic driver). Second, driving forces act over the entire working surface of the diaphragm, potentially offering more precise control with greater freedom from unintended resonance or vibration.”

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In my HE-5LE review I also pointed out two possible drawbacks to orthodynamic designs: namely, relatively high construction costs and low efficiency (or low sensitivity). Let me elaborate on both these points.

If you’ve ever have a chance to see an orthodynamic driver taken apart, you’ll find (as mentioned above) that the thin driver diaphragms feature fine-pitch conductive traces arranged in specific patterns; during assembly, the diaphragms must be very precisely aligned vis-à-vis the driver’s magnet arrays. Getting the alignment spot-on typically requires specialized assembly tooling plus extra quality control steps to ensure that tight tolerances are maintained. While precision tooling and extra assembly work add costs, you may find—as I have—that the sonic benefits of good orthodynamic designs more than outweigh whatever extra manufacturing costs may be entailed.