Despite some tuning quirks, the HiFiMAN HE400se offer tremendous value and are the best budget planars on the market.
HiFiMAN is one of the few brands that offer the most expensive, alongside perhaps the cheapest, pairs of planar-magnetic headphones in the market.
The HE400se are of the latter category and strangely enough, have a few of the latest technical breakthroughs employed by their more expensive siblings. It’s rare to see a pair of budget headphones offer so much on the spec sheet.
So are the HE400se too good an offer to be true, or is the hype justified? Read on.
- Form: Open-backed, over-ear
- Drivers: 1 X Planar magnetic driver, Stealth magnet design
- Impedance (Ohm): 25 ohm
- Sensitivity (dB): 91 dB
- Frequency Response (Hz): 20 Hz – 20 kHz
- Removable Cable: Y
- Source Jack: 3.5mm
- Cup/Shell Jack: 3.5mm
- Weight (g): 390 g
HiFiMAN has a simplified look to all their product packaging nowadays, and the HE400se box is no exception. The stealth magnet sticker points to the revised driver design of this model. I’ll discuss more on the driver redesign later in the sound section.
In the box
- HiFiMAN HE400se headphones
- 1.5m, 3.5mm to dual 3.5mm cable
- 6.35mm to 3.5mm adapter cable
The stock cable is horrendous in terms of ergonomics, and I highly recommend replacing it with a third-party cable.
The earcups are plastic and have a similar shape and size to the older gen, round-earcup HiFiMAN models. The headband and yoke are metal though, so there shouldn’t be much concern about durability.
The earpads have a perforated cloth material on the front with a solid pleather surround. The headband is foam-padded as well and I find the padding adequate. At the bottom, there are two 3.5mm TRRS ports.
The yoke design is similar to older HiFiMAN models and some newer ones like the Deva Pro and HE6se. There is a full range of motion across the Y-axis and a good amount of side-swivel to adjust to most face types.
Comfort and isolation
While the HE400se have a decent amount of clamp, due to the headband distributing weight evenly, no hotspots are formed. The stock pads are the HiFiMAN Palipads and they are comfortable even in the summer.
The weight is also lighter than many planar magnetic headphones due to the single-sided magnet assembly. Isolation is non-existent as these are open-back headphones.
HiFiMAN uses their tried-and-tested single-sided planar magnetic drivers on the HE400se. The most notable change in this revision is the stealth magnet assembly.
HiFiMAN HE400se Sound
The HE400se have a mostly neutral tonality with a bright tilt in the upper-mid and upper-treble regions.
The sub-bass is also rolled-off so the mids and treble sound even more up-front.
Bass response is mostly linear until around 40Hz, below which bass starts to roll off. As a result, sub-bass rumble is lacking, and kick drums, for example, lack the physicality. Mid-bass could also do with a bit more body since snare hits can sound sharper than they should.
Bass texture is average, not as well done as some dynamic drivers in this price range. However, said dynamic driver headphones also have more severe sub-bass roll-off or higher distortion in the bass, so it’s a fair trade-off.
Mids can sound shouty at times due to midrange suck-out near 1.5kHz. This is an old issue with this particular driver design, as the HiFiMAN HE-6 and their variants also suffer from similar midrange hollowness.
Due to this suck-out, upper-mids sound more intense than they should and are brought to the forefront. Fortunately, male vocals sound pristine with good tonality. It’s only certain high-pitched female vocals that exhibit occasional shrillness.
The treble is mostly even and not emphasized near the lower-treble. Upper-treble has some strong emphasis near 11kHz (to my ears) that adds “tizziness” to the sound, resulting in sharp snare hits and occasional glare.
If you are extremely sensitive to upper-treble, the HE400se might be fatiguing in the long run. Those who like airy treble should have no problem with this peakiness. I find this peak too much though and prefer to EQ it down (or modify the headphones, more on this below).
On a more positive note, the HE400se are very resolving considering their price. Part of it might be the treble emphasis, but even after EQ-ing the treble down you don’t lose a lot of information.
Soundstage and imaging
Staging is narrow, partly due to the upper-mid focus and partly due to the driver design not aiding in staging. Stage depth and height are above average, on the other hand.
Imaging is very good with precise localization in most soundtracks. This spatial accuracy also makes the HE400se good for gaming, though there are better headphones at this price that specialize in gaming tasks.
Dynamics and speed
Microdynamics are above-average for the price, with subtle shifts in volume picked up in most cases but certain nuances are missed. Macrodynamic punch is lacking due to sub-bass roll-off and a general lack of slam.
The HE400se showcase the typical planar speed. They will fare better in speedy or busy song passages than the typical budget dynamic driver headphones.
The most interesting part of the HE400se, to me, is how mod-friendly they are. I will explain a simple and effective modification – the ‘grille mod’.
The grille mod consists of basically removing the grilles from the cup. To do that, you have to detach the ring surrounding the grille and then the grille just pops out. This video is helpful if you’re unsure about how to go about it.
So, what improvements can you expect with the mod? Firstly, wider staging and better bass extension. Bass slam is also slightly improved and most noticeably the treble peakiness subsides.
Remove the grilles and you end up with a more pleasant-sounding version of the HE400se with even better staging and imaging.
The biggest downside of the grille mod is that the drivers are exposed. If you live in a humid or dusty climate, this might be a bad idea.
Air gap mod
Another less popular mod is to increase the air gap between the driver and pads. Basically, you break the “seal” between your face and the pads by inserting foam between the driver and the cups.
This mod increases the distance between the driver and the ear, and the sub-bass gets a bump near 60Hz. The bass slams harder and becomes noticeably punchier. However, bass roll-off is not addressed and lower-mids become recessed. If you like a lot of bass, this mod might be for you.
Or, you can just EQ these headphones. Unless you are increasing the sub-bass or upper-treble a lot, the HE400se can take a healthy amount of equalization.
The only other budget planar that I have tried are the Fostex T50RP mk3. They cost slightly more than the HiFiMAN and also require a lot more power to drive. The Fostex headphones are also semi open-back, unlike the fully open HE400se.
Just like the HE400se, the T50s are extremely modder-friendly. The driver inside is very capable and the construction aids in swapping out parts or adding dampening inside the cups. Check out this excellent rundown of the T50 series mods and the community surrounding them.
However, with the mods included, the T50 RP mk3 noticeably increase in price. Without the mods, I find their sound wonky and the comfort is poor.
In terms of sheer price-to-performance ratio, HE400se are still uncontested.
Where to Buy
HiFiMAN offers tremendous value with the HE400se, and they are kind of an anomaly in the headphone market. Although budget-priced, there are no glaring issues in the build or design. The driver is fast enough to offer a taste of planar, and they respond well to EQ.
Most of all, you can mod to your heart’s content and the price is low enough to not fret over breaking something. Aftermarket parts are also easily available, making the HE400se an ideal subject for modifications.
I recommend the HE400se to anyone interested in modifications, looking for a pair of budget planars, or just wanting a decent pair of planar magnetic headphones in general. They are not perfect, but they get a lot of it right while being light on the wallet.