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Drop + HIFIMAN HE-X4 Review

Planar Performance on a Budget

Christopher Coke Updated: Posted:
Hardware Reviews 0

Drop, formerly Massdrop, has become one of the most well-known collaborators in the headphone world. It’s approach is simple: partner with big brands to make custom versions of already popular headphones that enhance high points or respond to big critiques among headphone enthusiasts. While the Massdrop + Sennheiser HD-6XX headphones are probably its best-known headphone and established the company’s footing in this space, the Drop + HIFIMAN HE-4XX was another high-water mark, bringing planar magnetic headphones to a more affordable price point. 

Today, I’m looking at the brand new Drop + HIFIMAN HE-X4, Drop’s new entry-point to audiophile-grade planar magnetic headphones. They come in at $129 and feature an open-back design for increased sound stage, making them a particularly compelling option for gamers with separate mics. There are some trade-offs here but for the money, this is a great value headphone that’s a lot of fun to listen to.


  • Current Price: $129 (Drop)
  • Drop + HIFIMAN
  • Open back principle
  • Planar magnetic drivers
  • Color: Dark Grey
  • Soft-touch matte finish
  • Spring steel and hand-stitched protein leather headband
  • Focus-A hybrid ear pads
  • Adjustable sliders
  • Steel gimbals with black oxide finish
  • Black printing
  • Laser-etched serialization
  • Frequency response: 20 Hz–20 kHz
  • Sensitivity: 91 dB
  • Impedance: 25 ohms
  • Cable: 4.9 ft (1.5 m), removable
  • Plug:  ¼ in (6.35 mm)
  • Weight: 420g

At this point, HIFIMAN is a known commodity in the audiophile world, but since this X4 is likely to appeal to users approaching audiophile cans for the first time, some introductions are in order. HIFIMAN is well-known in the enthusiast world for its planar magnetic headphones. It’s been at the game for a number of years and has delivered some of the most respected sets in the business. The Sundara, for example, has been the reigning champion of the sub-$500 price bracket since its launch. HIFIMAN’s headphones go right up the ladder in price and performance well into the multi-thousand dollar zone. Virtually all of its best-regarded headphones use the driver technology found in the HE-X4. 

Image Credit: HELM Audio  

Though there are differences between its headphones, it’s well-crafted, well-tuned planar magnetic drivers are a through-line in what makes HIFIMAN’s line-up so popular (with rare exceptions like the HE-R10D which uses a dynamic driver). Rather than use conical dynamic drivers — think: speaker cones — planars use a flat sheet traced with conductive filament. On one or both sides of the sheet are arrays of magnets. These two elements work together to move the sheet and produce sound. Planar magnetic drivers often require more power to sound their best but are popular due to their excellent detail, particularly in the upper register, but are also known for their excellent bass performance (when tuned for it). It all comes down to how the driver is implemented but broadly speaking, a planar driver usually offers a level of crispness, detail, and “feel” than dynamic drivers. Planars tend to be more expensive, however, and often require extra power to sound their best, which is one of the reasons why the HE-X4 is such an interesting headphone. 

Unboxing and First Impressions

First things first: I was sent an early version of this headphone and retail packaging wasn’t ready. The headphone I’m reviewing today should be the same one that users receive but won’t come with the Slappa case. It does come with a soft cloth storage bag in addition to the cable. There’s nothing too remarkable here: the cable is rubber-coated but doesn’t get hung up on clothing and didn’t cause any microphonics I could hear. It connects to the headphone with a pair of 3.5mm jacks and terminates in a 3.5mm single-ended connection for use with computers, smartphones, and other digital audio players. Drop does include a 6.5mm adapter, so hooking up to higher-end audio equipment shouldn’t be an issue. 

The headphone itself feels robust and well-built. It features a steel-spring headband, so is very flexible and you won’t have to worry about it breaking over time. The yokes are also steel and attach to the band with a simple assembly that appears easily replaceable should it ever fail (assuming parts are made available).  The housings are the only part that’s plastic but it feels durable with no noticeable creak or give when squeezed.The open backs are guarded with metal grilles. They don’t have much give when pressed on but will rotate when twisted. It seems like these headphones would be fairly easy to open up for custom mods.

When it comes to padding, we have a faux-leather wrap around the headband and a set of HIFIMAN’s FocusPad-A ear cushions. There is very minor padding between the band and where it touches your head but it turns out to be just enough for long listening sessions. The ear cushions use a hybrid design with a velour face and pleather around the sides. There’s a noticeable lip between the leather and velour and it doesn’t look as clean as the stock pads on the Sundara or DEVA. The pads use different fabrics, so it’s a bit of an unfair comparison, but it just doesn’t look as nice. Still, they’re comfy.

Beneath those cushions lies the drivers. I don’t have exact sizing but these are large diaphragms capable of moving a lot of air. The HE-X4 uses a double-sided magnet array, similar to popular classic planars. Compared to the HE-4XX, the frequency response isn’t as broad and is limited to 20Hz - 20kHz versus 35 kHz. The drivers are more efficient with an impedance of only 25 ohms and a sensitivity of 91dB. Both my THX Onyx dongle DAC and Behringer UMC202HD audio interfaces were able to drive the headphones to distortion levels. My small Meizu HiFi dongle DAC couldn’t push them quite so loud but even that could push them to enjoyable levels with full bass response. 

That said, these simply won’t get as loud as some of the pricier planars out there and will distort when pushed too far via volume of low-end EQ. I suspect part of this might be because of how Drop has tuned the low-end response out of the box. More on that in the listening section.  

Comfort and Fit

At 420 grams, the HE-X4s are a moderately heavy headphone but Drop and HIFIMAN did a good job of making them comfortable to wear over long stretches. For this review, I used them regularly at my day job where I wear headphones for up to six hours at a time. I never experienced any hotspots or soreness from too much clamping. The weight is distributed well and the balance between clamp force and “head hang” is well done. 

Even though I’m not the biggest fan of the Focus-A hybrid pad look, they are unquestionably comfy. They’re not exceptionally breathable but my ears only ever felt warm and never hot. Of course, we’re not yet in the summer months, but these pads should remain more comfortable thanks to their velour faces warding off contact sweat. I wish they looked a little more refined but that’s a small concern when they actually feel so nice to wear. 

Listening Impressions

First and foremost, these are a fun headphone. At $129, Drop and HIFIMAN are targeting more of a mainstream audience and the result is a headphone that highlights the qualities most newcomers hear about planars before trying one for themselves: punchy bass that reaches low, clear mids with nice texture, and non-fatiguing treble. They’re not the best in any one area but they make for an enjoyable listen that’s a far sight better than most headphones you’ll find at a department store at this price. 

Putting them on for the first time, the first impression I had was “Sundara-lite.” There is a nice sense of space with different instruments being pulled apart and clearly discernible. The Sundara’s felt almost like microscopes with how clearly they pulled apart the layers of music. We’re not at that level here, but a gentler sense of verticality exists. Like the Sundaras, you can close your eyes and picture how each song comes together, how the tracks lay on top of one another, and, particularly in the mids, you get a nice sense of detail. I particularly enjoyed electric guitars with these cans. Coheed and Cambria’s “The Telling Truth” was an excellent example of this, and I could clearly hear the nuances of the multiple guitars weaving in and out, accentuated by snappy snares and cymbal crashes. 

The soundstage is fairly wide but not exceptionally so. As an open-back, it achieves a good sense of space, but it’s not at the level of the Sundaras or Gold Planar GL2000s. We’re still better than a closed-back by a long stretch but mids in particular have a tendency to sound fairly close in. This can work to its benefit in acoustic tracks or games when you want to hear exactly where an audio cue is coming from, and depending on whether there’s additional reverb or atmospherics, the soundstage can transcend to feeling large. Still, it varies, so I’d describe the soundstage as good, not great. 

Drop definitely tuned up the bass with these headphones, lending them a warmer signature overall. The sub-bass really stands out and songs sound full and large. The X4s can definitely slam and border on rumble when the song calls for it. It’s not overstated, however. For example, sticking with Coheed for a moment, in “Welcome Home” the kick drum thumps and injects energy and drive into the verse. But then in a gentler track like “The Light and the Glass” it’s able to step back and let the acoustic guitars breathe. 

That said, the bass isn’t tight and can often feel soft and rounded at the edges. The X4s don’t have the same speed as a set like the Sundara’s or HD-58Xs in sub-bass response even though it’s punchier than either of those headphones. Likewise, it’s clear that the Drop pushed the bass from the get-go because there’s limited headroom to push it further before distortion sets in. There are times when it feels like it’s just on the cusp of breaking through into a powerful, slammy response but just can’t break through. Bad? No — especially because the levels at which distortion is audible are beyond what I consider safe. It’s still a fun listen but this is an area where you can tell it’s entry-level positioning.

When it comes to mids, guitars and vocals really come forward. With the bass being as tuned up as it is, that’s a good thing and allows the X4s to sound bright in the areas you want it to sound bright. As a musician, I find the tuning here more true to life. In PVRIS’s “Only Love” (acoustic version), the bass and sub-bass make a lush bed for the song but the guitars and sparkle on top and ring out with excellent clarity and detail. “Loveless,” on the other hand, really highlights how the soundstage can be great with the right songs. The atmospherics are excellent, the acoustic guitar rings out just above the bass with nice texture and detail, and Lynn Gunn’s vocal sounds almost intimate.

The HE-X4 also handles treble well, but wasn’t the star of the show for me. It sounds more rolled off to my ear (as of this writing, there are no frequency graphs available) with cymbal crashes decaying quickly. High hats, however, come forward nicely. That said, the highs lack the same detail as the mids and are overall less remarkable. Still, sibilance was never a problem for me and I never found the X4s to be sharp or fatiguing in the upper register.


For gamers looking for a headphone that will sound great without costing an arm and leg will be in good hands with this headphone. Compared to the average gaming headset, the sound quality is much better. The detail, imaging, and bass response are all going to be improvements from normal headsets — remember, more bass doesn’t mean a better gaming headset. Instead, these have a tuning that’s punchy and detailed and draws out the most important details for competitive games. The directionality and positioning is also quite good.

Final Thoughts

The Drop + HIFIMAN HE-X4 is a great headphone for the money. It’s not going to win any awards for detail retrieval, particularly in the high-end, but at $129 its performance punches above what I would expect. It’s comfortable for long listening sessions. It’s a fun listen and a great introduction to the world of planar magnetic headphones. 

The product described in this article was provided by the manufacturer for evaluation purposes.
  • Comfortable over long listening sessions
  • Very fun tuning - solid bass and detailed, forward mids
  • Very well priced
  • Solid all-around pick: music, gaming, and movies
  • Drivers will distort at high volumes/EQ tunings
  • Cushions could use refinement
  • Bass can feel soft at times and there is lacking detail in both low and high-end frequencies


Christopher Coke

Chris cut his teeth on MMOs in the late 90s with text-based MUDs. He’s written about video games for many different sites but has made MMORPG his home since 2013. Today, he acts as Hardware and Technology Editor, lead tech reviewer, and continues to love and write about games every chance he gets. Follow him on Twitter: @GameByNight