REVIEW / MEASUREMENTS: (Mass)Drop + HiFiMan HE-4XX Planar Magnetic Headphones (with Brainwavz XL Round Hybrid earpads). Maintenance if the earcup detaches.

Well, as I've mentioned previously, I don't really need more headphones. ;-) Alas, I could not resist picking up these minty Drop + HIFIMAN HE-4XX Planar Magnetics locally used at a price I could not refuse! I also love how they look with the classic headband. The matte "midnight blue" color looks like a dark charcoal with a subtle powder bluish tinge.

I know there have been different opinions on the build quality of these headphones. Some of the early units had issues with right-left imbalance, driver failures, and broken hinges. According to this post, it looks like replacements with serial number 5XXX have many issues fixed. My unit here has serial number 57XX.

The hinge where it interfaces with the headband feels robust on this unit and I think the build quality is very good. The steel gimbal and metal sliders seem like they will be able to hold up to daily use. No complaints there. I did have an issue with the part interfacing the ear cup which I'll discuss below.

The stock cable is a little short for my taste at around 5'/1.5m (6' would be better for my desktop use). Notice that the cable is angled 90°, terminated with a 3.5mm connector which is fine for mobile use. I think a straight cable would have been preferred since most buyers would likely be using these open headphones at home almost exclusively. I like the soft, pliable nature of the cable although I have read some complaints that it can kink and fail. I don't think there's an issue, replacements are not expensive anyway.

These have good-sized 60mm planar magnetic drivers. Not the largest of course, headphones like the Monolith M1060 claim 106mm driver size which should help with bass output, but as usual, size isn't everything. ;-) Certainly larger drivers than the Dekoni Blue/Fostex T50RP discussed previously.

As you can see, already these are not by any means small headphones! Depending on your head size, the proportions could already look a bit ridiculous. Certainly nothing like the ridiculousness of the Abyss 1266 Phi TC though.

Another view of the planar magnetic driver from the inside when I removed the earpad:

The "midnight blue" color shows up quite nicely in this picture in natural light.

Notice that the plastic clips on the inside of the earpads slide under the thin metal ring around the driver in the 4 corners. Usually not too difficult to install and detach with the soft bendable earpad plastic ring.

These cans I have are not stock. The original earpads have been replaced with the Brainwavz XL Round Hybrid Earpads (be mindful of the larger XL 110mm diameter size with 65mm inner diameter, standard round 100mm replacements would not fit well) with plastic mounting rings. Users have complained about the durability of the stock pads after a year of use. I'm sure these aftermarket pads will change the measurements a bit so be aware. However, if you're interested in an aftermarket pad, the measurements will at least give you an idea of how this combination presents.

Notice that the Brainwavz pads are thick 3cm memory foam but not angled like stock HiFiMan "FocusPad-A" pads. Velour material touching the face/ears, with pleather around and it's fenestrated internally. Workmanship looks good and the pleather feels great.

I was tempted to test out some very inexpensive Defean Velvet/Leatherette replacement pads (<CDN$20) which I have been told are about the same quality as the OEM; maybe another time if I have the need.

The original owner included some balanced cables with the headphones:

These are terminated with 2.5mm TRRS and I'd need a 2.5mm to 4-pin XLR adaptor to use them with my Drop + THX AAA 789 amplifier. Thus far, I have not used the balanced output yet, but have ordered an adaptor to try later.

Some time in later 2019, the Drop + HIFIMAN HE-4XX was updated with 3.5mm plugs for each ear cup. The one I have here is the original dual 2.5mm version. I don't believe there is any evidence that this makes a difference to the sound since the drivers are the same. I suppose a larger connector should be more robust.

These headphones feel good on the head with the Brainwavz pads. They're clearly heavier headphones (430gm without cables) than something like the extremely light AKGs. The clamping force is a bit stronger than something like the Dekoni Blue and is about the same as the Sennheiser HD650, especially with these thicker ear pads. The semicircular headband works well for me to distribute the weight. Comfort is good overall but I definitely notice the weight of the cans on the head with prolonged listening sessions (more than an hour). Also, I'm quite sensitive to clamping force so whether it's these or the Sennheiser HD650, I find I take them off every hour or so for a little break from the extra pressure.

I. Measurements

Here are my "core" measurements - remember this is with the Brainwavz XL Hybrid Round aftermarket earpads which will have an influence:

Three things stand out for me right from the start:

1. The driver matching is excellent between R & L, from 20Hz to 20kHz.

2. This headphone has good bass and sub-bass.

3. There's a mid/upper-mid dip which will definitely have an influence on the sound.

The first of these - driver matching - was quite a pleasant surprise considering the price. I might have just lucked out with getting this well-matched used pair (and cheaply!), but given that I don't consider myself as having especially good luck, this is certainly auspicious for the headphones. Driver matching is inherent with the headphones and will not be affected by the earpads (unless somehow the earpads are very asymmetrical!).

As for the bass, it's deep and plentiful. No difficulty at all ensuring a good seal with the Brainwavz pads when measuring. Essentially "flat" all the way to 20Hz; and this is measured with compensation using the Harman 2018-like AE/OE curve which incorporates a bass boost below 200Hz which I think most listeners (include myself) find preferable. I'm sure in no small part this is a result of the larger planar magnetic driver compared with something like the Fostex T50RP / Dekoni Blue.

Unfortunately, at least with this combination with the Brainwavz XL Hybrid earpads, there's a bit of mid and upper-mid range recess into the low-presence frequencies up at 4.6kHz. The frequency response bounces back sharply above 5kHz however. Yes, this is audible and will be discussed below.

The waterfall plot showing a 40dB dynamic range over 10ms is certainly not as clean as my other open-back headphones with quite a bit of roughness. Due to the strong bass abilities, I expected lingering low-frequency content into 10ms. There appears to be resonance around 200Hz and 500Hz. Compare these irregularities to the smoothness of the AKG Q701 for example.

Electrical impedance and phase as with most planar magnetic drivers are quite flat. We're looking at about 43Ω impedance across the audible spectrum (spec calls for 35Ω which is lower than what I measure here). There is a slight resonance peak at 88Hz in the impedance graph which only goes up to ~44.5Ω. Notice how flat the phase is - hugging 0° all the way.

Voltage sensitivity works out to 107.5dB/V which is pretty good. This is equivalent to 94dB/mW measured which is right around the 93dB/mW official spec. In fact, I was able to enjoy using these headphones at normal listening volumes even with my smartphone connected to the inexpensive Soditer USB-C DAC and it sounded pretty good. As usual, I would recommend using a high quality headphone amplifier for best sound.

It's good to see the low harmonic distortion at 95dB SPL output. <1% THD essentially all the way down to 20Hz. 

Noise isolation:

Obviously not great given these are open headphones. There's basically no attenuation of outside noise until around 1kHz. However, by 5kHz and beyond it actually does filter out quite a bit of the external high frequency noise by up to -17dB.

As for sound leakage, these headphones are about as bad as it gets:

With an average of 92.3dB at 1" away, this works out to 71dB at 1 foot. It's so noticeable that my wife who works across from me on the computer desk was surprised by how loud the leakage was, wondering if I was going to go deaf listening to these even at quite normal levels! Even the Sennheiser HD800 leaks less with <62dB SPL at 1'.

Above, we see the 100Hz bandwidth-limited square waves looking pretty good. There's a reasonably steep rise, peaks around 1.25ms (a bit faster than my modded Dekoni Blue) without much roughness (compared to say the Sennheiser HD800).

II. How does it sound?

As usual, while I believe the objective results are more important, hence presented first, I did make sure to listen to the headphones before putting them on the measurement jig and wrote down some impressions of the sound over a couple of evenings.

I'm impressed by how well these headphones handle acoustic music. For example, John Renbourn's album Sir John Alot of Merrie Englandes Musyk Thyng & ye Grene Knyghte from 1968 is recorded remarkably well. Tonality of the flute, guitar, and percussion on "Morgana" was rich, sounded realistic, and with excellent "spatial" separation between the instruments (far left flute, center guitar, right percussion). If you like British traditional folk, make sure to give this album a listen!

Likewise, I really enjoyed revisiting Ry Cooder's atmospheric Paris, Texas soundtrack the other night with these. Lovely just how the large headphones envelope the listener. Excellent detail retrieval - guitar plucks reproduced with wonderful precision on the attacks.

My only complaint would be with vocals. Voices can sound a bit too recessed, even slightly "hollow" at times (don't know if better with stock pads or if accentuated with the Brainwavz XL earpads). The reason is obvious looking at the frequency response. Looking around the Internet, it's always interesting to see the different viewpoints offered. I'm with those who feel that the mid-range is a bit too laid back (like this review) which is why with some vocals - particularly females like say Norah Jones's "Shoot The Moon" on Come Away With Me, sounds like she's a bit further away than the accompanying bass and guitar. Furthermore, the vocal tonality sounds slightly duller than it should, reminiscent of the "Sennheiser veil" of the HD650. This is not as obvious with vocals at a lower register. For example, Holly Cole singing "Whatever Lola Wants" on the recent album Montreal (DR9, 2021) is not affected as much given her lower pitched voice. And most male vocalists would be only mildly affected.

Some have said that the trebles are too sibilant. Maybe, but I'm much less bothered by that than the relative midrange recess.

These 'phones can rock hard on Led Zeppelin's The Song Remains the Same (2018 Blu-Ray remaster). It's an old live recording from 1976 so resolution isn't great but the energy in the performances is good and documents a "peak" era for the band. So long as your headphone amp can handle it, this headphone will happily "bring it". Even at higher-than-healthy volumes for prolonged listening, I didn't notice any objectionable distortion. Because the recording is a bit mid-range recessed, I found this album matched poorly with the laid back HE-4XX upper-mid; certainly midrange boost preferable.

Modern pop/rock like Bon Jovi's Bon Jovi 2020 (DR6) sounded "alright" at best on account of the perverse self-inflicted subpar sonic quality of the recording. Honestly, modern pop like this will have many audible distortions that will clearly show up with good headphones. Sure, I can still enjoy a track like "Limitless" but this is in spite of the poor sound quality and it's simply not conducive to repeated listening. I sometimes wonder if the aging rockers (Jon Bon Jovi is only 59 currently but who knows about hearing ability) recognize just how far down the sound of their recordings have dropped compared to their output from the '80s and '90s - a shame! Rock demands dynamics.

No issues at all with reproducing the head-pounding bass on "Virtù e Fortuna" (Westworld: Season 2). Dynamics excellent on Jim Keltner's "Improvisation" (The Sheffield Track & Drum Record).

As usual, other than binaural music, "soundstage" is typically not something I spend much time considering with headphones. It's mainly "all in the head" sound with varying left/right panning. The Drop + HIFIMAN HE-4XX is no different. What is excellent is the sense of clarity and "space" around instruments and voices on good audiophile recordings. For example, on Blue Coast Collection Vol. 2, the excellent clarity of the vocals, guitar, and piano on "On The Moon" was good enough to imagine being in the room with the artists even if missing an actual 3D illusion due to the headphone presentation.

[As discussed last year, sound quality is more a reflection of recording and production sensibilities rather than whether something is "hi-res" as in 24-bits, high samplerate, or DSD. Blue Coast's albums like the one above are good examples. When looking at these albums in an audio editor, we clearly see that noise floor is relatively high and the high-frequency content >20kHz has noise and other anomalies due to the use of an analogue process along with DSD noise shaping. A 16/48 downsample will easily capture the content IMO for most of these albums, and save you storage space.]

III. In Summary...

Like I said, I got these at a price I could not refuse. Brand new, at less than US$200, the Drop + HIFIMAN HE-4XX is one heck of a planar magnetic headphone for not a lot of money! No surprise that they've sold something like 42,000 of these over the years. The non-stock Brainwavz XL Round Hybrid Earpads I'm using here are comfortable and an affordable alternative whenever the stock pad wears out. 

I know people would use the term "entry level" for something in this price range. Honestly, I don't think this way because in reality, given the performance levels these days, I believe even a humbly-priced device like this can take on the sound quality of many much more expensive headphones in a non-price-tag-biased blinded A/B shootout. We are well along the "diminishing returns" curve that we should not expect "day and night" differences among reasonably good quality hi-fidelity devices these days. Simply wonderful just how much quality one can get with a small audio budget in the 21st Century. The main thing to listen for (if mine here is reflective of other HE4XX's out there) is that recessed upper-mid. I have no major concerns otherwise.

While I'm sure there are sonic differences beyond the external physical characteristics and cosmetics, these headphones are related to the contemporary HIFIMAN HE-400i (also can be had <US$200). Going up the HIFIMAN line of headphones, there's the well-regarded Sundara, Ananda, Arya, and their top-of-the-line Susvara (staying with the planar magnetics). Of them, I've only listened to the Sundara at a friend's place about a week ago and although I don't have any objective confirmation, I actually preferred the HE-4XX's (+ Brainwavz pads) more visceral bass response while the Sundara seemed better in the upper-mid but risked being too bright.

To improve the sound of these HIFIMAN HE-4XX + Brainwavz XL Round Hybrid pads, here's the EQ I use to bump up the mid/upper-mid:

Bands 1 & 2 most important, the others optional. I suggest turning on "Headroom management" given the EQ gains.

Sounds fantastic! Vocals brought forward pleasantly, more focused, especially female voices and improves the overall sense of dynamics.

I've been rotating among 3 main headphones for most of my listening in the last while - these Drop + HIFIMAN HE-4XX, the Sennheiser HD800, and my modded Arch-Mod5 Dekoni Blue described a couple weeks back. While they're very different physically and soundwise, I don't have a huge preference among the 3 as it depends on my mood and what music I'm listening to.

As much as headphone listening is needed sometimes, for comfort, a great soundstage, and good ol' bass impact, it's back to the sound room, speakers, and sub as much as possible! ;-)

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Maintenance: If the hinge detaches...

Since changing the ear pads may require a bit of force and twisting, at one point, the hinge between the yoke and the insertion point into the earcup detached like this while I was having a look at the driver underneath:

Notice the earpiece has a hole into which the metal screw mount insert is embedded and has gone loose.

First things first... No need to panic if outside of warranty period. ;-)

It seems this is not a terribly uncommon thing to happen and I hope the newer versions have had this issue addressed.

Take a small Torx screwdriver and unscrew the brass (?) insert and rubber ring from the yoke:

Now put a small amount of Loctite or Superglue along the inside of the ear cup hole where the metal "coupling nut" goes into. Don't use too much obviously - make sure the glue doesn't overflow out and mar the cup or seep deep into the headphone!

Stick the "coupling" screw thread metal piece back in - let it set and dry for a few minutes like so:

Before re-screwing together, you can bend the Y-shaped yoke to conform closer to the cup's diameter to lower tension and likelihood to "pop out" again. Some users have considered this as the first "mod" you should do when you first buy one of these headphones. I cannot disagree and have done this for both sides.

Screw the yoke back in place with the rubber ring (don't screw too tight).

Good as new. Yeah, I wished they had a more robust design! Well, these headphones are built to a certain low price point so slight maintenance over time might not be completely surprising. On the bright side, at least it's not worse like something actually snapping into pieces or stripped screw threads. This is easy to repair.

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So guys and gals, anything happening in the audio world in the last week? I'm not seeing much in the news. With Apple's WWDC coming June 7-11, I guess people are watching for the imminent availability of lossless/Atmos streaming content on Apple Music. 

We're approaching the summer season so things do tend to be slower in general. Likewise for me, while there's not much in the way of travel or major vacations coming up, I'm hoping to enjoy some time just listening to music, reading a good book, or watching movies with the family as COVID-19 restrictions should be relaxing substantially over the next month. Still working on some upcoming articles of course; time allowing after the day job. ;-)

Enjoy the music! Hope things are well with you and yours...