Drop + Grell OAE1 Signature Headphones

General Information

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SPECS​

Headphones
  • Drop + grell
  • Headphone type: Open-back
  • Ear coupling: Over-ear
  • Drivers: Biocellulose dynamic drivers
  • Sound characteristic: Front oriented diffuse field equalization
  • Adaption to the individual hearing curve: Soundfield pinna interaction
  • Nominal impedance: 38 ohms
  • Frequency response: 12 - 32,000 Hz (-3 dB), 06 - 44,000 Hz (-10 dB)
  • Sound pressure level (SPL): 106 dB (at 1 kHz 1 VRMS)
  • Total harmonic distortion (THD): 0.05% (at 1 kHz 100 dB)
  • Weight (without cable): 375 g

INCLUDED​

Cable 1
  • 6 ft (1.8 m) Double-sided, silver-coated OFC cable
  • Connectors headphone side: 2.5 mm TRRS
  • Connector device: 3.5 mm stereo plug
  • Adaptor: 3.5 mm to 6.3 mm, screw-on
Cable 2
  • 6 ft (1.8 m) Single-sided, silver-coated OFC cable
  • Connectors headphone side: 2.5 mm TRRS
  • Connector device: 4.4 mm Balanced TRRRS stereo plug
Carrying Case

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Latest reviews

Evshrug

Headphoneus Supremus
This Challenger Takes a New Angle
Pros: +Comfortable to wear
+Comfortable to listen to
+Case is roomy enough to carry small accessories and a dongle DAC
+Earcups fold flat but aren't loose
+Two cables included, 4.4mm Pentaconn
+Dual-entry or single-entry cables possible, non-proprietary 2.5mm TRRS connector
+Earpads and headband can unclip for replacement
+Sub bass extension
+Textured and not one-note bass, elevated presence
+Relaxed Treble without being dark
+Pinpoint imaging
+Different degrees of depth perception
+Great platform for adding Spatial Audio processing or HRTF binaural recordings.
Cons: -Some people may put it on backwards
-Case is large
-Ear cup entry jacks are deep, must push firmly to connect cables
-Strain reliefs on the ear cup entry jacks may be too narrow for your existing 3rd party cable collection.
-Headband skin is Polyurethane.
The grell OAE1 was not what I was expecting. At first, when news that Axel Grell was making an analog, open back wired headphone, I thought it was squarely within his wheelhouse, the perfect move to show what grell is best at. But the show impressions on prototypes started trickling in, and it was a bit confusing because there were multiple different tunings being explored. Then, people started quoting a high-profile reviewer or two who were setting the expectation that the defining characteristic was a treble spike, combined with fears that the more open a headphone is the weaker the bass presence would be. Remembering my past mixed feelings about earspeakers and the very open, also-biocellulose-driver Sony MDR-MA900 and F1, I almost declined to review the grell OAE1 when Drop reached out to me (no compensation or editorial oversight, and as far as I know this is just a loaner). However, my curiosity won out, and my at-home impressions are far better than I was expecting.
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Let’s start describing the headphone with the way most people first interact with a headphone, the presentation and build quality of the OAE1.

I’d guess the packaging will be something to encourage recycling, but the semi-circular black case is worth keeping. It would fill a significant portion of a backpack if attempted to carry it that way, but it’s way more transportable than a storage box; the OAE1 earcups fold flat so it isn’t too thick to fit, the case’s smooth design doesn’t have any protrusions, plus there’s a contained space between the headband and earcups area that holds the two included cables (more on that in a bit) and has enough room for me to fit a USB Dongle.

The OAE1 design itself is essence of headphones, evoking smooth circular shapes and perhaps a smiley face 😀. Katrin, Axel Grell’s wife and a graphic /product designer by trade, is to thank for the sleek modern design language, and perhaps also influenced the choice to use matte finish rounded aluminum and contrasting black PU leather instead of the wood accents of other brands and the plastics dominating Axel’s past headphones. The silver grilles strongly evoke studio microphones 🎤.
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Little but thoughtful design touches abound. Lifting the OAE1 reveals that it’s still very light for a full-size headphone, and the earcup extension mechanism has a generous range and smoothly has infinite adjustment with well-dampened resistance against slipping. No need to worry about elastic bands wearing out here, and my question was answered that the headband and earpads are also clipped on and easily replaceable. I asked about the headband because my balding head was concerned that the smooth arch aesthetics would create a hot spot at the peak of my head, but Axel told me the center point of the headband actually has a lower density foam inside, so even though it doesn’t look like an HD 650 headband it does kind of feel like one, with a more moderate clamping force. The pads themselves are very plush and soft, heat escapes easily from them easily and I was told they’re also quite acoustically open. To wear them, the OAE1 earcups swivel a bit more than 90° without flopping around.

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My first con: it was not obvious at first glance to see the tiny L & R legends, which are not bright and printed on the 2.5mm cable plug protection nubs, and I suspect it will be common to see people put the mostly symmetrical looking headphone on backwards. My sample is a pre-production factory sample, so the cosmetics might change in the production model (tuning will not). Looking inside the pad cavity though, it’s very easy to see the extremely front-biased drivers even though they’re covered by a black dust-and-hair shield, and the jacks are placed and angled so that the cables will drape easily on the wearer’s shoulders. The OAE1 does come with a thin 3.5mm cable with a nice screw-on 6.5mm adapter and 2.5mm TRRS plugs for each earcup, and also a cloth-braided 4.4mm terminated balanced cable that, very uniquely, has a single 2.5mm TRRS tip that can plug into either earcup, with the connection to the other earcup made via a hidden cable in the headband. These configuration options are great for purists or usage at a desk with the cable routed to one preferred side.

Taken on its own merits, the OAE1 is tuned for entertainment rather than analytics, and yet delivers timbre and music insight with the ease you would expect from a master craftsman. The frequency balance has forward but not extreme mid bass and upper mids, with loads of extension into the treble and sub bass range, HiFi level separation and clarity of simultaneously playing instruments. The headphone is able to convincingly reproduce both intimate and expansive soundstage, often in the same song if it’s well-recorded.

The elephant in the room is the most radical part of the OAE1 design. Whether labeled as innovation or gimmick, the extreme angle of the drivers does have an impact on the sound and is more extreme than I’ve seen on any headphone previously, unless perhaps putting a RAAL or Mysphere at their most open setting, and even then I think those drivers would be more distant from the ear than the OAE1, and have certainly not been able to produce this level of sub bass. Grell has been very careful NOT to claim his design creates “In-Front Localization (IFL),” but that’s an industry term specifically referring to that sense of a phantom center, like the headphones are able to recreate the center speaker of a surround system. There is a bit of modesty and careful setting of expectations though… the angled drivers DO reflect substantially off the folds of the wearer’s ear shape, folds and cups that are more unique than fingerprints, and makes full use of our body’s physical mechanism for pulling more timbral information out of a performance, but this sense of timbre “realism” does help increase the believability of distance and soundstage (along with careful L/R driver matching), and also makes the OAE1 an excellent candidate for adding Spatial Audio processing, which DOES achieve not just a phantom center but also a full surround experience with the right recording media.

Music Listening Notes:
I think the best way to describe the sound of a headphone and how its frequency balance and performance traits work together is by sharing listening notes… plus it’s fun to share and discover music! I’ve shared this playlist before, and maybe my dear reader has sampled them to hear what they sound like on familiar gear, but let me briefly explain the standout features of each of these music tracks:

Notes based on using a midrange DAC/amp USB dongle, the Apogee Groove, and Apple Music HiRes.
Track 1: Unfinished Sympathy - The opening booms and record scratches dig deep and resonate in a large, reverb soaked, underground sounding space. The timbre of this track hit me just so, YMMV but this headphone gave me a pleasant spine-tingling sensation, one of only 5 headphones ever to do that for me.
Track 2: What Is the Code - This synthetic/cyberpunk song demonstrates how the OAE1 can perform the sound suck-out before the bass drop, also frequency sweeps from mids to bass showing how the amplitude doesn't drop off and maintains a tight bass even with extended notes.
Track 3: The Great Divide (Seven Lions Remix) - This electronica track shows the leading edge impact of mid bass hits, also how the big bass doesn't bury the airy female vocals that float around the stage before the vocalist snaps into place. The voice is clearly processed through a vocoder, but it fits the song, and the vocals also don't sound shouty alongside the bass, but this is still clearly a fun rather than analytical tuning.
Track 4: Moonlight Sonata: I. Adagio sostenuto (Arr. for Cello & Electronics) - Less fantasy, more organic. The rain and thunder at the beginning gave me shivers again... but the headphone is able to portray the distant rumble and percussive pitter-patter well. The violin is not veiled, it has good presence despite being mic'd from a distance (or at least made to sound so by the sound engineer) but still has sparkling moments.
Track 5: White Summer - A sparse but lively arrangement of just guitar, bongos, and a recorder (or some kind of woodwind, I'm not an expert haha). It's definitely good to play around and find the sweetspot for where the headphones rest around your ears for this song... helps get rid of some mid suck-out and sound more natural. Wearing the OAE1 backwards on this track collapses the soundstage, arranging all the instruments along a 1D line from ear to ear, also muffles the highs and sense of the recording room almost entirely. A slightly more lo-fi recording than the next one, but still fun to listen to.
Track 6: Strive (Binaural) - This is an intimate track, it sounds like we're up on the stage with the string performers, but also its easy to hear the reverb of the big empty hall. This was a song recorded with headphones in mind, without any special processing it has a great sense of imaging and soundstage.
Track 7: Dronning Fjellrose - Another track specifically great on headphones due to Dolby Atmos processing baked into the recording file, the OAE1 is able to pinpoint place the singer and each instrument in their own space on the stage. Axel is careful to point out that the OAE1 by itself doesn't apply In-Front-Localization... but here the sound is very 3D.
Track 8: Liberty - Forward and intimate female vocals. Not hearing any sibilance, but you can easily hear her wet mouth and breathy softness. Forward, but for me it's still comfortably short of being shouty, it just sounds like there's less separating me and the singer, but this might be a good track to EQ to taste.
Track 9: We Are Not Alone - This song has two layers... the saxophone that performs at the forefront, but the mood sounds very different depending on the headphone if all the little flourishes of instruments in the back are audible alongside the frontman. On the OAE1, the playful and weird slurring and shifting instruments playing simultaneously with the sax and rhythm bass are all played confidently and my brain is calmly able to hear each instrument or just wash in the full arrangement without straining to focus.
Track 10: Sakura - Lo-Fi Chill song. The binaural beats here work, for a headphone with forward bass and vocals it's still easy to sit back and relax to something like this.
Track 11: Dark Fate - GOOD MORNING! This ought to wake you up! Good impact and slam, switching between grand clamor and intimately hopeful guitar. If you were going to try EQ'ing the headphone, this would be a good evaluation song to check that you don't lose what makes this headphone special.
Bonus: Hotel California (Live on MTV, 1994) - The OAE1 sounds very rich here! The bass and sense of depth is great here too.

Movies: Dredd and Wall*E
I remember the first time Dredd was brought onto Netflix for streaming, I had been loaned a Sony MDR-MA900, which was also an extremely open and easy to drive headphone with a Bio-cellulose driver like the grell OAE1... but the MA900 felt like listening to tiny speakers, the sound was clear with almost no resonance BUT the bass and treble extension was weak, making guns wheeze and explosions melancholy. Fast forward like 12 years, the OAE1 is even more open, but it has a full cinematic feel with a better sense of air and especially weighty explosions that really sell the excitement and adrenaline of the action movie. On an entirely more peaceful and curious note, WALL*E's opening few chapters are dialog free, focused almost entirely on Ben Burt's brilliant sound design. These opening scenes were portrayed by the OAE1 with a big sense of stage depth or even open air, selling the desolate open spaces convincingly, but the focused moments with just a little robot's antics felt important rather than laid back, appropriately intimate (and curious).

Gaming: Helldivers 2 and CoD: MW2 (2022)
These familiar games don't have their own Spatial Audio processing built in... so on PC or Xbox the default would be regular stereo, with strong separation between the left and right channels (separated by your head, of course). You will be able to get a good feeling for distance, and generally left or right, but you won't be able to hear the difference between front and rear sounds. However, with a bit of crossfeed, or ESPECIALLY with some spatial audio processing applied like Sony's Tempest 3D Audio that comes with the Playstation 5, the processing considers what something like 120 speaker positions would have sounded like by the time their sound waves would have reached your ears, and then the headphones play that back in realtime. WITH Spatial Audio/ HRTF Processing / Headphone Surround applied to the audio signal, the OAE1 provides a spectacular platform for very precise positional imaging that smoothly pans around you, and it's easy to hear someone running along the other side of the wall and predict exactly when they'll come into view. Helldivers is a little more vague than CoD, because the bots and bugs don't make footstep sounds, so you just hear when enemies or allies call out, but you do hear everything... tonight was the first time I noticed the backpack shield makes it's own quiet shimmering sound. Bonus: the Hitman series of games are usually more methodically paced, but it's super immersive to hear people talking all around you (and easier to hear where someone shouts "Hey!" from if they spot you), really making me feel in the game.

Stream-of-conscious first impressions on head-fi here… https://www.head-fi.org/threads/axel-grell-headphone.967413/post-18088983

DAC/amp comparisons
CONSOLIDATING NOTES, WILL EDIT

Compare & Contrast with popular reference headphones
CONSOLIDATING NOTES, WILL EDIT

“The customer is always right, in matters of taste.” There will be people who prefer more niché tunings, or require a different form factor such as closed backs or in-ears. This may not be the headphone for treble-heads, or people who want softer bass. Sometimes male vocals sound less prominent than female vocals. I have a relative who can’t stand audio that is “too clear,” without a lot of resonance and slow decay its sensory overload for her. The cost is not free.

That said, this might impress people who wished for a less expensive HD 800S with great soundstage and clarity, but wished for more body in the mids and especially bass for a less airy and more grounded emotional weight. Anyone who has wished for an HD 650 that has a bit more sparkle in the highs, deeper sub bass reproduction, and less head clamp. The HD 6XX has sold over 190,000 units exclusively on Drop as of the time of this review, and the HD 650 before it has sold an unknowable hundreds of thousands more, so I think it’s a safe bet to say the majority of people will find something to like here.

The OAE1 is the make-it-or-break-it point for grell audio, so Axel is using everything he has learned in his approximately 30 years of industry experience PLUS his best tradition-breaking ideas that he couldn’t try while working for someone else to pull out all the stops and make a headphone squarely in his wheelhouse. I love the design touches added by his wife, and no doubt literally the entire Grell family influenced the design. Comparisons will inevitably be made to Axel’s previous designs such as the HD 800 and the venerable classic HD 650, but if anyone could surpass the HD 650 it would be the man who originally created it. To put it in other words, this is Axel’s ideal headphone for the masses. The marathon comfort both physical and audible, impressively solid sub bass, pinpoint soundstage imaging, and last but not least energetic and lively timbre are all points from my wishlist - for me it’s like grell audio checked off every single one. How often do you get a headphone with both a WOW factor and you don’t get tired of using it?
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Evshrug
Evshrug
I'd guess the amount of copper underneath the insulation is about average gauge, the rubber around the single-ended 3.5mm cable is wider than a typical USB cable but once it splits to enter each earcup the individual cable "sides" are about 2/3 the diameter of a typical USB cable. The balanced cable is thicker all along its length, and covered in fabric. They're both thicker than an IEM cable 🤷‍♂️
roncri
roncri
S
Skeza
@Evshrug do you still have the unit? Are you able to provide some measurements and pictures of the 2.5mm inputs. So I can see if adapters will fit.

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