HiFiMAN’s HE-400i differs from its original HE-400 in several essential ways, which I will attempt to enumerate in a ‘bullet point’ list below:
- It is lighter (HiFiMAN says about 30% lighter than competing designs).
- It features an all-new frame/headband design that makes for a dramatic (and I mean really dramatic) improvement in comfort and adjustability vis-à-vis the earlier frame design used in the HE-400, HE-500, and HE-6 models.
- It features new, user replaceable, ‘beveled’ ear pads whose sidewalls are covered in so-called Pleather, but whose touch points with the wearer’s head are covered in velour material; the new pads are very comfortable.
- The HE-400i uses an updated, so-called ‘single-ended’ planar magnetic driver that appears to have been influenced by the design of the new HE-560 (the term ‘single-ended’ denotes the fact that the driver has a magnet array behind—but not in front of—the planar magnetic diaphragm surface, meaning there are no obstructions between the face of the driver and the wearer’s ears—apart from a thin, acoustically transparent protective fabric cover).
- Rated sensitivity has increased ever so slightly from 92.5dB for the HE-400 vs. 93dB for the new HE-400i.