Grell OAE1 Headphones: Don't Buy If You're Unsure

Introduction

The Grell OAE1 headphones are a new product designed by Axel Grell, formerly the chief engineer at Sennheiser and now the founder/owner of Grell Audio. They feature an unconventional structure where the drivers are positioned significantly in front of and away from the ears. This design choice appears to be aimed at minimizing pinna interactions and potentially enhancing spatial representation of sound. The intention seems to be to achieve a more natural and realistic audio reproduction.



Although I was not 100% sure if his claims are legit, as a huge fan of non-traditional acoustic designs, I was highly tempted to get my hands on the pair, expecting something at least different if not necessarily better. After weeks of waiting after pre-order was placed, I finally received the product this morning and spent approximately 6 hours evaluating them. This included an hour of light break-in followed by extensive listening to various tracks. It's important to note that these are initial impressions from the first day of use.

Ok, how do they sound? Well, sorta mixed. See below for more.

Good

Exceptional (Some) Spatiality

Axel seems to have prioritized spatiality above all else in the OAE1's design (even at cost of . This is evident in two key areas:

1. Front-to-back Soundstaging: OAE1 excels in creating a deep, layered soundstage with a properly distant virtual center. This aspect is unrivaled by products in similar or lower price ranges. Note that I don't think their left-to-wide soundstage is noteworthy. More on this later.
2. Reduced In-head Localization: OAE1 significantly minimizes the sensation of sound originating from within the head, a common character with headphones. While not quite achieving the out-of-head experience of loudspeakers, it's among the best headphone products I've experienced in this regard, regardless of price point.

Good Low-bass Extension

Despite my initial anticipation about potential limitations due to small drivers and their distance from the ears (my bass expectation was around HD650 or slightly better), the OAE1 delivers surprisingly good bass extension. With some quality compromise (only when compared to orthros, estats, or higher-end moving coil dynamics), the low end reaches down to 20-30 Hz without noticeable attenuation. The balance between low, mid, and high bass is satisfying, with a pleasing downward tilt towards the midrange, reminiscent of the HarmonicDyne Athena in the budget category.

Balanced Bass-to-Midrange Transition

This is not necessarily OAE1's distinct strength. However, contrary to some early purchasers' complaints about overwhelming bass masking the midrange, I found the tonal response from bass to midrange to be well-balanced. There's no perceptible hollowness in low-frequency instruments or low-tone voices, which typically indicates a bass-midrange imbalance.


Not Good

Ergonomics

The most significant drawback to me is the headphones' ergonomics. The headband is too small for larger heads, reminiscent of Audeze MMs (which I would describe as "big-head torturerl"). Combined with very tight clamping force (tighter than a fresh HD650), this led to discomfort during extended listening sessions.

Treble Performance

To my ears, their highs sound dry (more so than HD560S), closed-in, and lack sparkle. While this appears to address early prototype complaints about over-brightness and sibilance, it may have been overcompensated. The result is suppressed overtones and air, leading to a poorly balanced high-frequency range. This, combined with good lows and prominent upper mids, can sometimes result in a somewhat cuppy or boxy sound. And for these reasons (possibly confounded by other unknown factors), the perceived soundstage is neither very expansive nor open, which contradicts their marketing claims.

Minor Midrange Coloration

There's a slight biodyna coloration in the midrange, reminiscent of what I often hear from other bio-cellulose dynamic drivers as well. However, this is a minor issue compared to the treble and ergonomic concerns.


Tentative Conclusion

Grell OAE1 presents a mixed bag of impressive spatial performance and potential sonic shortcomings. It's worth noting that these initial impressions may evolve with extended use as the brain adapts to the sound signature (which I am observing myself throughout the day). However, the ergonomic issues may pose a more persistent challenge.

At this stage, I never recommend the OAE1 to those who aren't specifically sure about how well OAE1 fits their preference -- needless to say, if you search for a solid primary pair of headphones, just walk away. They feel more like a proof of concept than a fully matured product. If that's what you look after, the distinctive sound may hold its own against even higher-end models in some aspects, which is intriguing for "sth different"-seekers like me. However, the potential for polarized reception among buyers would be extremely high, I guess.

I'll continue evaluating this product over the next couple of weeks before making a final decision on whether to keep or return them. The unique sonic presentation is compelling, but only if I can overcome the ergonomic hurdles to ensure sufficient use.

 

Measurements and Quick Analysis

These measurements were taken using my MiniDSP EARS rig.

Frequency Response Measurements

1. Positional Sensitivity: Horizontal placements (front vs. back vs. center) produce more significant changes than vertical placements. This aligns with my subjective experience. My optimal listening position likely falls between the blue and purple curves.
2. Low-End Extension: Consistent with subjective impressions, the measurements confirm excellent low-frequency extension.
3. 5.7 kHz Dip: A narrow, extensive dip at 5.7 kHz appears in the measurements. This is likely exaggerated due to coupler artifacts, as I don't perceive a significant loss of detail in this region during listening.
4. Treble Response: The measurements show milder recessions in the brilliance region than my subjective experience suggests. While the plot indicates a prominent 4 kHz presence peak, my perception is slightly different. Subjectively, I hear less presence and more recession in the brilliance region than the measurements indicate.
5. Off-Axis Treble: It's important to note that due to the OAE1's structure, both ears and measurement couplers receive more off-axis treble sound compared to conventional headphones. This inherently complicates the translation of measurements to perceived sound.

Distortion Measurements

Distortion plots have been omitted as the levels of harmonics were lower than the noise floor in my testing environment.

Cumulative Spectral Decay as Waterfall

1. Decay Speed: The overall decay is not particularly fast. This is unsurprising given that OAE1 is more closed and damped than its appearance might suggest, which limits how quickly the signal can dissipate.
2. Decay Uniformity: Despite the moderate decay speed, the pattern across the spectrum is remarkably even. There's virtually no indication of disproportionately stored energy. This characteristic may contribute to the dry sound I perceive.
3. 4.4 kHz Resonance: Some resonance is observed around 4.4 kHz, which may be related to the coloration I noted in my listening impressions.

The measurements largely mirror my subjective impressions, while also revealing some interesting discrepancies, particularly in the treble region. I'd re-emphasize the unique design of these headphones presents challenges in measurement interpretation.

 

How much of that 4.4kHz ringing do you feel might be attributable to the EARS rig? I get a lot of similarities with other headphones that use angled drivers— could be interactions with the genuinely bad pinnae and that Pringles can ear canal. Did you have a flat plate rig to work with too perhaps?

Biodyna midrange is honestly not a bad thing to me, definitely piqued my curiosity just now. The aggro upper mids and that lack of treble extension is a bit of a buzzkill, but may be an interesting listen with the staging and all. Depth > width any day

 

That's very good point and I (have to) mostly agree. I am still puzzled why some headphones don't show such patterns while others do. By the way, the resonant place is very slightly different. EARS resonance centers at 4.7khz (see the rig's default calibration curve) while the peak in this waterfall is at subtly lower frequency. I still don't know if or how much they are related to each other. lol

 

When I looked at the Drop product page for these, my first thought was "I wonder if they have a 6k peak" and then I laughed when I saw the FR graph.

Overcompensation indeed, from 10k down the lowest point is 6k. I felt like Axel tried to head-off any "dummkopf, you just made another OG HD800" accusations. Then I went, "I bet he ruined the treble." Guess I was right

 

I'd be curious to try these. Some reason ALOT of headphones sound like the mids are coming from behind me. Unless it's an on ear as I find those have the most natural stage presentation.

 

@ChaChaRealSmooth and I were chatting a while ago about how it seemed like part of why we were both partial to dynamic driver headphones was BECAUSE they were more focused in how they projected sound, great rolloff when even the slightest bit off-axis; planars with large diaphragms (ignoring all the other challenges that seem to come with that design philosophy) do seem to tend towards larger sonic images, but with less defined edges to those images. I'm wondering whether that exaggerated ~4500Hz resonance, specifically on the EARS rigs, might be any sort of correlateable with certain diaphragm geometries that tend towards beaming, e.g. in speakers. The fact that this is a smaller diaphragm similar to HD6-- and Focal suspended far ahead could be exacerbating the reaction.

And yep the EARS rig's primary resonance is higher up by a bit but the angling could be screwing with that a bit? I'm inclined to think the pinnae are to blame somewhat.

 

I got a pair too, been trying to provide better context versus the new toy syndrome hype on the other site.

I’ve measured my pair on my GRAS clone, with Harman 2013 as a reference in these:


Compensated for people that prefer that:


As you can probably tell, these have a fuckton of bass. They’re closer in bass to the Focal Radiance:


I wouldn’t necessarily mind this bass if it was clean, as I don’t really have a bassy headphone kicking around, but no matter what I’ve plugged it into be it my Esoteric A100, Dartzeel clone, ATI 2007, or even a Liquid Spark, it sounds pretty muddy. This headphone should have been marketed more towards gamers, which I guess considering Drop is now owned by Corsair, isn’t too far from the mark.

I also measured impedance and effects of different OI:



Regarding the spike in Vtory’s measurements, this is actually a function of the driver. There’s a notch filter in the cup to tame it:

 

Hah, that reminds me of the Ultrasones that used to (still do??) have a pair of diodes in each cup to protect from overdriving.

 

How restrictive is the front damping on these, by the way? Makes me wonder if they took a brute force approach to taming the treble on these similar to how Beyerdynamic addressed the treble issues on their DT880s with felt discs covering the entire diaphragm, just with that added notch filter to address that pronounced 4500Hz elevation.

That, paired with a Qualia-looking placement, could go a ways towards explaining how it seems like it's not presenting a lot of detail despite being able to convey good staging. How's resolution on this compared to something like the HD600 or HD560S, @Ishcabible, @Vtory, and microdynamics as applicable to something this dry sounding?

**********
This is a tangent and purely anecdotal by the way but I heard from someone on Discord that the HD560S seems to be going through some running changes (for the worse); the pads they ship with now appear to more resemble the pads that come on the HD559, but even when measuring an older and a more recent HD560S using the same pads using a rig based on an IEC711 clone they found that the newer sample had greatly elevated treble.

Not sure if anyone on here's purchased an HD560S recently but I'd be curious to know whether others agree that their initial listening impressions could be summed up as "HOLY CRUD THAT'S BRIGHT"

 

I actually have an answer to both! First I’ll show the front damping:


And how it measures without it:


As far as resolution, I put the HD560S and HD6X0 in different tiers of resolution, as I hear texture and decay with the 6X0 that I can’t with the 560S. The OAE1 is roughly in the same tier of resolution as the 560S for me at best case, but the overwhelming amount of bass does seem to mask more than I’d like for most music.

 

@Ishcabible Legend, thanks for the effort!

My main headphones since I let go of the HP-3s (which I do occasionally miss) have been the HD600; my one relative living next door to me mains an HD560S; I was just wondering which between those two tiers of resolution (cuz I agree, they are VERY different in terms of resolution) this new toy was closer to

Didn't know this rocked a biodyna driver until just now with your photos! That'd track with Vtory's impressions then, nice. Never was a fan of aggressive front damping with either the X00 Ebony or the HP-3, robbed them of too much nuance IME. The J-Pop levels of sparkly air frequencies aside, how audible is that mid-treble trough? I'm still a basshead at heart so feel like this could come close to sounding great (YMMV) with just a bit more refinement to the design, but one wonders how it stages without all that front damping?

 

This is highly subjective, and personal preference plays a big role (aka YMMV). In my experience, I used to find the HD560S to have better detail retrieval (ability to distinguish small frequency differences) than the HD6X0s, while HD6X0 out-resolve in dynamics (ability to separate fine nuance). Nonetheless, I'd say they're in a similar ballpark -- neither reaches the high-end levels I demand. Still, they offer pleasing performance for sub-$500 bucket.

The OAE1 falls into a similar tier for me, but perhaps slightly behind the HD560S and HD6X0 (perhaps due to driver distance). I've compared them to other budget-ish options I am having, like the HD650K, O2, and RS2x. Ultimately, I believe preference plays a larger role than objective performance differences.

One area where the OAE1 (among the mentioned things) stands out is its imaging location and sound-staging dimensions (not necessarily huge or wide). I'd rank them as follows in terms of spatiality:

OAE1 > O2 = RS2x = HD560S > HD650K (more spacious to less spacious)

 

Thanks for all your effort to disassemble your unit. That explains why the initial reception was flipped (bright to dark).

I impulsively picked up one last year when the factory refub went on a sale (around usd 80-85). I also participated HD560S loaner tour long ago. And I don't think my unit is particularly brighter. My impression largely remains same.

 

Thanks @Vtory! So could just be wild production variance or a lemon unit, else it's a far more recent change with the HD560S than the last year? Sorry for the tangent, but hopefully others can chime in on that front, rather curious. Senn didn't move production facilities again, did they?

Staging's always been a pretty important thing to me but not at expense of resolution and the like. I actually don't hate how the OAE1 measures without all that front damping up until just under 8kHz (again: basshead), but everything after there is just wild. IIRC those GRAS 43AG-style clone couplers oughtn't be taken at face value past mid-treble but IIRC it oughtn't be too difficult to account for those shortcomings with compensation, plus I'm pretty sure Ishca knows his shit.

(Sorry if spamming this thread, genuinely curious about these, hope to get more folks with impressions in!)

 

Correct, treble varies massively between heads so it’s not going to be particularly accurate. However, I subjectively hear more treble than measured while I’m sure some hear less, and it’s a factor of not only the headphone but the individual treble sensitivities of the listener

 

I was completely underwhelmed by these initially, setup is : OAE1 SE>Liquid Platinum balanced>Liquid Platinum DAC

Going back and forth from my clears (clears balanced into same setup) and to my surprise not only were frequencies muffled, the soundstage was non existent and entire instruments were missing!

Decided to run the clears single ended as I have never utilized the LP that way, maybe something was up with that output. Nope it was the OAE’s, after switching back a few more times I decided to box these up, they were going back.

Packaged everything up and couldn’t quite give up on them, I had to be missing something, right? I unboxed them again, unraveled the SE cable, plugged them back in with a little more force (almost enough that I thought that I may break the tiny 2.5mm connector) and heard a click, hmmm I don’t remember hearing that the first time, plug the other side in the same way to an audible click. How the hell did I eff that up the first time? Make sure that you plug the cables in until you hear a click!

Much better sound now, but something is still off. It turns out that these are very position specific to find the best sound, I am also guessing that the location may be different for everyone.

I find that at louder than my normal listening levels the OAS’s really come to life and the sweet spot for me at these levels is with my ear completely centered in the headphone. Going to burn these and my brain in for awhile.

 

Mine are supposed to be here Monday. Lots of up and down on Head-Fi. Very curious what they will sound like to me.

 

I feel you. In fact, I've encountered this more often than average audiophiles lol. Particularly when it comes to trrrs connectors..