The HE400se is a full-size but lightweight large-diaphragm Planar Magnetic headphone that practically anyone can afford which can be driven by most sources adequately. I say most sources because these are happiest with lots of power. I would say drive directly with a good DAP yes, directly off a phone, no.
I measured the diaphragm of this driver and I got a more or less measurement of 80mm from the round diaphragm with silver traces. Each driver uses a 3.5mm TRS connection which uses the tip for the positive contact.
The driver specs out as having a frequency response of 20Hz to 20 kHz, an impedance of 25 ohms with a sensitivity rating of 91dB SPL. The 91dB SPL sensitivity rating I think is the specification that holds back efficiency here.
If you go back just 5 years, it would have been somewhat crazy to think you could get a full-sized Planar Magnetic headphone of this quality for a buck and a half.
Most of the cost in making planar magnetic headphones goes into the magnet assembly and driver manufacturing process due to the high levels of precision and consistency that must be obtained. So let’s talk about the magnet structure a bit.
STEALTH MAGNET DESIGN
Some years back, lots of people started installing a modification on their planar cans to improve the sound by minimizing refractions. Manufacturers such as Audeze brought their own version in with Fazor technology with sonic improvements over their original non-Fazor editions.
HIFIMAN came up with a similar but simpler solution over the last few years and it is indeed implemented on the HE400se. Hifiman calls this concept the Stealth Magnet Design.
By simply controlling sound waves passing through the magnet structure, HIFIMAN was able to eliminate refractions and sound interference by reducing wave diffraction turbulence. This is the equivalence of sound bouncing off walls and objects from a speaker to then reach the ear off phase and in different times causing massive phase issues and sound purity degradation.
What HIFIMAN did here was to make the magnet assembly almost sonically invisible as to not interfere with sound waves coming off the diaphragm as it goes into the ear cup and to me, HIFIMAN was successful.
I thought the HIFIMAN HE400se was an exact reincarnation of their HE400S when I first laid eyes on them because the cup size and color were basically identical, but not quite so. Besides the fact that the driver is not the same one used on the HE400S, the cup has also been reworked.
HIFIMAN worked on making the cup less prone to vibration and stiffened up the design plus also improved on the recessed 3.5mm connectors. As previously stated, the tip is positive and the sleeve negative which is the common HIFIMAN pin configuration so you could use basically any HIFIMAN wire and this also makes it easier to find a good aftermarket cable.
The pads themselves resemble Pali pads but they have stiffer foam inside and look a few millimeters thicker. Their construction is similar to the Pali pads using a hybrid design with perforated faux leather on the inside, cloth on the flat part that touches your head, and faux leather, a non-perforated type for the outer side.
The pads are angled, thicker in the back, and equally comfortable to Pali pads except for the added stiffness. The cup size is the usual 100mm size which uses the HIFIMAN clip-on design for the pad mount.
FOURTH GENERATION HEADBAND
HIFIMAN has been through some headband changes and to be honest, I miss their first design because it was comfortable plus a more low profile design up top.
The second iteration was the head strap style used on the 400i and some top-tier models like the HE1000 which was a comfortable design but the yokes on some models had issues. The third iteration was the Sundara and the Ananda-style headband.
This new style of headband looks familiar and will probably become HIFIMAN’s standard headband for now since the same one is being used by them on lots of their present models, from the Deva to one of their top models, the HE-R10 and now the HE400se.
COMFORT & ISOLATION
You get a somewhat open feeling with the HIFIMAN HE400se but external sounds are not muffled much which is fine since this is an open back design so do not expect any sound isolation with these. There are other open-back designs that isolate more than these.
Comfort is very good but I could slightly complain about the top being a touch too stiff and also too thick looking but the arch design on top distributes the weight rather evenly with a moderate amount of clamping force but never tight to a point of causing discomfort. Hopefully, the cushion will soften up with use.
The combined low weight of 370 grams and the moderate clamp with comfortable pads makes this a comfortable set and long gone are the days of the heavy planar designs.
I do like the HIFIMAN HE400se design overall but not so much the cable assembly that comes in the box. It does terminate in the common 3.5mm TRS and HIFIMAN do include a 6.35mm converter but If we analyze the cable from the tip up we run into some issues.
The jack is a common TRS 3.5mm plug as stated but does not have a recess extension and if you use a device with a recessed jack or use a rubber cover or case you will not be able to easily connect this wire. I had to remove all my phone covers for example to use it. You could only connect it to a flush-mounted plug.
Second, the wire, although it’s a silver wire which seems to be good quality stuff with good connectivity and signal transmission, the stiffness of the wire makes it pretty bad especially for portable use. It seems to be a memory wire that remembers how you bend it with an almost pre-tinned wire stiffness. Long story short, you will probably seek out a different wire.
By the way, the box everything came in a new style of HIFIMAN packaging that I find to be adequate enough to give the buyer a nice unboxing experience but gives the assurance feeling that the box is not a large portion of the product final cost.
You do not get a huge amount of accessories, however. These include: