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Drop + Grell OAE1 Signature Headphones
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- bass comfortable grell open soundstage
Ichos
Reviewer at hxosplus
Pros: + Bass emphasized tuning
+ Class leading sub-bass extension
+ Punchy and impactful bass
+ Fan and exciting
+ Mid-range presence
+ Treble clarity and definition
+ Good resolution and transparency
+ Spatial soundstage with sharp imaging
+ Less clamping force versus the Signature
+ Comfortable and lightweight
+ All black is a beauty
+ Good build quality
+ Affordable
+ Class leading sub-bass extension
+ Punchy and impactful bass
+ Fan and exciting
+ Mid-range presence
+ Treble clarity and definition
+ Good resolution and transparency
+ Spatial soundstage with sharp imaging
+ Less clamping force versus the Signature
+ Comfortable and lightweight
+ All black is a beauty
+ Good build quality
+ Affordable
Cons: - Too much bass for critical applications
- Bass is slightly lacking in tonal accuracy
- Bass technicalities could be better
- Slightly artificial sounding treble
- Not a speaker-like soundstage as advertised
- The soundstage is not especially wide
- The cable sockets are too narrow limiting aftermarket options
- Carrying case and balanced cable are not included
- May not fit people with larger heads
- Bass is slightly lacking in tonal accuracy
- Bass technicalities could be better
- Slightly artificial sounding treble
- Not a speaker-like soundstage as advertised
- The soundstage is not especially wide
- The cable sockets are too narrow limiting aftermarket options
- Carrying case and balanced cable are not included
- May not fit people with larger heads
Axel Grell is a renowned audio engineer credited with the creation of some of the most esteemed headphones globally, including the Sennheiser HD600, HD650, and HD800. After many years of dedicated service at Sennheiser, Mr. Grell made the decision to establish his own brand, leading to the inception of Grell Audio.
To facilitate promotion and sales, Grell Audio formed a partnership with the community-oriented platform Drop. The inaugural product from Grell Audio was the Drop + Grell TWS/1, a wireless earphone set for which I had the honor of writing the world premiere review. Currently, Grell Audio has returned with a full-sized headphone, the Drop + Grell OAE1.
Drop + Grell OAE1
The Drop + Grell OAE1 is a full sized, open back headphone with a revolutionary driver geometry that promises to make them sound like speakers in front of the listeners head. The OAE1 positions the drivers further out and in front of the ears to create a soundfield that’s stunningly natural. It’s an innovative yet undeniably intuitive acoustic concept that Axel Grell first implemented in high-end Sennheiser headphones like the HD800 and now has tried to perfect it.
The two speaker membranes of the Grell OAE1 are positioned at an angle to the ear to project the sound waves as if they were coming from a source directly in front of the listener. The drivers are broadband transducers with bio-cellulose diaphragm.
The baffle also contributes to the unique listening experience that the OAE1 promises. The Grell OEA1 has an extremely large, curved and open baffle, which is complemented by an open ear cushion. This design allows the sound to spread naturally without being reflected by large closed areas. The high-precision stainless steel mesh guarantees high acoustic permeability and controlled bass reproduction. This prevents sound coloration and resonances.
Widening the soundstage even further, Axel Grell and his team developed ear-cups that are 90% open metal mesh and a woven stainless steel acoustic-damper mesh, both of which allow sound waves to pass through with minimal interference.
You can read the whole design concept of the Drop + Grell OAE1 here.
The signature edition
The Drop + Grell OAE1 initially debuted as the "Signature" model, a limited edition collector's item with only 1,000 units available, which quickly sold out within a matter of weeks.
This Signature model was priced at $349 and showcased silver-painted ear cups and hinges, each adorned with Axel Grell's engraved signature. Additionally, the headphones came with a premium carrying case and included two cables: one featuring a 3.5mm plug and the other a balanced 4.4mm plug.
The standard version
Grell Audio and Drop have joined forces to introduce the standard version of the OAE1, which shares the same tuning as the Signature model but incorporates a couple of notable modifications.
The most significant change is the reduction of clamping force, which has been adjusted to 3N from the 3.5N found in the Signature edition, resulting in less pressure on the head. While the Grell OAE1 still exerts a firmer grip than many headphones available on the market, it now offers improved comfort and less pressure on the head.
In terms of aesthetics, the standard OAE1 showcases a more understated black finish, favored by Drop, along with prominent L and R indicators within the ear-cups to assist with orientation and placement.
The standard Grell OAE1 is priced $50 lower; however, this reduction comes at the cost of the practical carrying case and the balanced cable. These accessories are quite beneficial, and I would willingly pay the additional $50 to obtain them. It would be advantageous if Drop provided two bundle options, allowing customers to make a choice.
Non Audio stuff
The OAE1 is constructed with high-quality materials and features a simple, minimalist aesthetic that is likely to attract a wide audience. The ear-cups consist primarily of a large metal mesh, complemented by a woven stainless steel acoustic damper mesh. Aside from the outer rings, which maintain a silver finish, the remainder of the design is coated in black.
The ear-cups are secured to the headband using aluminum clamps. The headband itself is rounded, padded with memory foam, and wrapped in PU leather. The central section of the headband incorporates lower density foam to prevent the formation of pressure points.
The velour ear pads are generously thick and filled with firm memory foam, ensuring that the drivers are positioned at an optimal distance from the listener's ears, which is crucial for the tuning process.
The mechanism for adjusting the headband operates smoothly and is sufficiently tight to maintain its setting. All components of the headphones are designed to be user-replaceable.
The circular ear pads are sufficiently wide and deep to fully encompass the ear while allowing for ventilation. However, the velour surface does not provide a cooling effect, and some perspiration may occur after extended use. The ear pads possess a firmer texture than usual, which may require an adjustment period. The ear cups feature a 180-degree swivel mechanism for enhanced positioning.
The headband offers adequate comfort, enabling prolonged use of the headphones for several hours without the necessity for breaks.
The Drop + Grell OAE1 is a lightweight headphone, weighing 375 grams. With a reduced clamping force, it delivers a comfortable fit comparable to that of most other headphones.
It is noteworthy that the headband adjustment mechanism does not extend significantly, even at its maximum setting, which may result in an inadequate fit for individuals with larger head sizes. Personally, I find the fit to be just barely adequate at the maximum adjustment. This concern was raised by the community regarding the Signature model; however, the headband design has not changed in the standard version.
The cable and accessories
The Grell OAE1 is designed to accommodate both dual and single entry cables, as each ear-cup is equipped with a socket that accepts a 2.5mm plug. An integrated overhead wire facilitates the sharing of the input signal between both drivers when utilizing a single entry cable, allowing for connection to either side. Additionally, the headphones can support both dual and single entry balanced cables.
Nevertheless, the input sockets feature an extended plastic tunnel that serves to protect the plug from unintentional bending; however, this design also restricts the diameter, making it challenging to locate aftermarket plugs that are compatible.
Given that the standard version of the Grell OAE1 is supplied with only one single-ended cable, finding a suitable balanced cable may prove difficult due to this diameter constraint. Therefore, it would be prudent for Drop and Grell Audio to consider offering the original balanced cable that was part of the Signature model bundle.
Except for the cable you only get a 6.35mm plug adapter.
Audio stuff
The headphone features a nominal impedance of 38Ω and a sensitivity of 106dB/Vrms, making it easy to drive without the requirement for specialized amplification. My primary usage has been with the FiiO M23, the iBasso DX180 and the Aune S9C Pro, utilizing the balanced cable from the Signature version.
The Grell OAE1 delivers an astonishing level of bass that may be difficult to comprehend upon initial listening. It requires a brief period to acclimate and fully grasp the auditory experience. The sub-bass extension is remarkable for an open-back headphone, particularly one at such an affordable price point. It is challenging to identify another open headphone that can reproduce frequencies as low as 20Hz with such fidelity. Axel Grell has achieved a tuning that simulates the sensation of having subwoofers positioned near the ears while maintaining impressive clarity in both the midrange and treble frequencies.
The bass is accentuated, deviating from a neutral response, which is unexpected given the designer's background with the HD800. However, this emphasis is not so pronounced as to reach excessive levels that would compromise tonal accuracy. While it is accurate to say that the Grell OAE1 does not offer the most tonally precise low-end, its exuberantly tuned bass creates an engaging and enjoyable listening experience. It is capable of handling classical and acoustic genres, provided one is willing to overlook its lack of neutrality and embrace its more relaxed character. Personally, it may not be my preferred choice for classical music, but it excels with a wide range of other genres, particularly modern electronic and trance music.
In terms of technical performance, the Grell OAE1 generally exceeds average standards. The bass is tight and well-controlled, free from noticeable echo or reverberation, while also being highly impactful and dynamic. It features rich textures and demonstrates quick response times, along with commendable definition and layering. However, it struggles with complex and dense bass lines, where it tends to become one-dimensional, slightly blurred, and somewhat bloated.
More Audio stuff
The Grell OAE1 excels in maintaining an impressive balance and presence in both the mid-range and treble, even with its pronounced low-end. The bass is well-defined, ensuring it does not overshadow or interfere with the mid-range, which is allowed to express itself with clarity and remarkable resolution for its category. The overall tuning is notably balanced, providing satisfactory tonal precision and a natural timbre. The OAE1 is both musical and engaging, offering a rich harmonic variety that connects the listener to the music, effectively reproducing both vocal and instrumental performances.
The mid-range stands out as the headphone's most compelling feature, and in my opinion, it presents a more appealing and balanced sound than the renowned Sennheiser HD650, despite its emphasis on the upper mid-range. Axel Grell appears to have achieved a more refined and sophisticated tuning with the OAE1, resulting in a sound that feels more lifelike and realistic, while minimizing listener fatigue.
The treble is bright and lively, serving to balance the pronounced low-end and prevent an overly warm or dark sound profile. It possesses a brightness that is neither harsh nor piercing, and it resolves adequately for its category, though it may not be perceived as particularly spectacular or brilliant. The Grell OAE1 can be somewhat unforgiving with lower-quality recordings, particularly when paired with bright sources.
A notable drawback regarding the treble is its occasionally unnatural and metallic timbre, which can sound somewhat artificial at times. There is a degree of sterility and dryness, coupled with mildly suppressed overtones and a relative lack of harmonic richness. However, the perceived effects can vary significantly depending on the music and recording quality; for instance, classical music may not be as satisfying, while listeners of electronic music may find little to complain about.
The soundstage
The soundstage presents a varied experience, as it does not create the impression of the OAE1 resembling speakers positioned in front of the listener, contrary to its claims. It does not exhibit a greater expansiveness or holographic quality than most headphones and is notably less wide and immersive than the Sennheiser HD800. Nevertheless, it successfully delivers impressive spatiality with a pronounced central image that appears to emanate from a location outside the listener's head. While the Grell OAE1 may not provide extraordinary expansiveness, it offers a remarkably spacious and open sound within its confines, boasting class-leading depth layering and positioning, even when compared to significantly pricier headphones.
Conclusion
The Drop + Grell OAE1 represents a scientific endeavor by a renowned acoustic engineer, resulting in a headphone that, while very good, may not cater to all preferences. It may not excel in rigorous critical listening and does not fully deliver on its promised speaker-like attributes. However, it does provide an unprecedented sense of spatiality and features a deep bass response that is emphasized yet maintains a balanced overall tuning.
The bass performance is impressive for an open-back headphone, and the tuning approach is vibrant and enjoyable, making it particularly well-suited for casual listening without sacrificing sound quality. The newly released standard version has improved upon the comfort issues found in the Signature model and is offered at a more accessible price point. While the Drop + Grell OAE1 may not resonate with everyone, it is likely to cultivate a dedicated following among enthusiasts.
The review sample was kindly provided free of charge in exchange for an honest review. I don't use affiliate links. The price of the Grell OAE1 is $299 and is exclusively available from Drop. You take advantage of the pre-order discount and get them for $249.
Disclaimer: For various Google indexing reasons, parts of this review may have been processed with an automatic paragraph rewriting tool. However it reads exactly the same as the original content that is available in my website.
To facilitate promotion and sales, Grell Audio formed a partnership with the community-oriented platform Drop. The inaugural product from Grell Audio was the Drop + Grell TWS/1, a wireless earphone set for which I had the honor of writing the world premiere review. Currently, Grell Audio has returned with a full-sized headphone, the Drop + Grell OAE1.

Drop + Grell OAE1
The Drop + Grell OAE1 is a full sized, open back headphone with a revolutionary driver geometry that promises to make them sound like speakers in front of the listeners head. The OAE1 positions the drivers further out and in front of the ears to create a soundfield that’s stunningly natural. It’s an innovative yet undeniably intuitive acoustic concept that Axel Grell first implemented in high-end Sennheiser headphones like the HD800 and now has tried to perfect it.
The two speaker membranes of the Grell OAE1 are positioned at an angle to the ear to project the sound waves as if they were coming from a source directly in front of the listener. The drivers are broadband transducers with bio-cellulose diaphragm.
The baffle also contributes to the unique listening experience that the OAE1 promises. The Grell OEA1 has an extremely large, curved and open baffle, which is complemented by an open ear cushion. This design allows the sound to spread naturally without being reflected by large closed areas. The high-precision stainless steel mesh guarantees high acoustic permeability and controlled bass reproduction. This prevents sound coloration and resonances.
Widening the soundstage even further, Axel Grell and his team developed ear-cups that are 90% open metal mesh and a woven stainless steel acoustic-damper mesh, both of which allow sound waves to pass through with minimal interference.
You can read the whole design concept of the Drop + Grell OAE1 here.

The signature edition
The Drop + Grell OAE1 initially debuted as the "Signature" model, a limited edition collector's item with only 1,000 units available, which quickly sold out within a matter of weeks.
This Signature model was priced at $349 and showcased silver-painted ear cups and hinges, each adorned with Axel Grell's engraved signature. Additionally, the headphones came with a premium carrying case and included two cables: one featuring a 3.5mm plug and the other a balanced 4.4mm plug.

The standard version
Grell Audio and Drop have joined forces to introduce the standard version of the OAE1, which shares the same tuning as the Signature model but incorporates a couple of notable modifications.
The most significant change is the reduction of clamping force, which has been adjusted to 3N from the 3.5N found in the Signature edition, resulting in less pressure on the head. While the Grell OAE1 still exerts a firmer grip than many headphones available on the market, it now offers improved comfort and less pressure on the head.
In terms of aesthetics, the standard OAE1 showcases a more understated black finish, favored by Drop, along with prominent L and R indicators within the ear-cups to assist with orientation and placement.
The standard Grell OAE1 is priced $50 lower; however, this reduction comes at the cost of the practical carrying case and the balanced cable. These accessories are quite beneficial, and I would willingly pay the additional $50 to obtain them. It would be advantageous if Drop provided two bundle options, allowing customers to make a choice.

Non Audio stuff
The OAE1 is constructed with high-quality materials and features a simple, minimalist aesthetic that is likely to attract a wide audience. The ear-cups consist primarily of a large metal mesh, complemented by a woven stainless steel acoustic damper mesh. Aside from the outer rings, which maintain a silver finish, the remainder of the design is coated in black.
The ear-cups are secured to the headband using aluminum clamps. The headband itself is rounded, padded with memory foam, and wrapped in PU leather. The central section of the headband incorporates lower density foam to prevent the formation of pressure points.
The velour ear pads are generously thick and filled with firm memory foam, ensuring that the drivers are positioned at an optimal distance from the listener's ears, which is crucial for the tuning process.
The mechanism for adjusting the headband operates smoothly and is sufficiently tight to maintain its setting. All components of the headphones are designed to be user-replaceable.
The circular ear pads are sufficiently wide and deep to fully encompass the ear while allowing for ventilation. However, the velour surface does not provide a cooling effect, and some perspiration may occur after extended use. The ear pads possess a firmer texture than usual, which may require an adjustment period. The ear cups feature a 180-degree swivel mechanism for enhanced positioning.
The headband offers adequate comfort, enabling prolonged use of the headphones for several hours without the necessity for breaks.
The Drop + Grell OAE1 is a lightweight headphone, weighing 375 grams. With a reduced clamping force, it delivers a comfortable fit comparable to that of most other headphones.
It is noteworthy that the headband adjustment mechanism does not extend significantly, even at its maximum setting, which may result in an inadequate fit for individuals with larger head sizes. Personally, I find the fit to be just barely adequate at the maximum adjustment. This concern was raised by the community regarding the Signature model; however, the headband design has not changed in the standard version.

The cable and accessories
The Grell OAE1 is designed to accommodate both dual and single entry cables, as each ear-cup is equipped with a socket that accepts a 2.5mm plug. An integrated overhead wire facilitates the sharing of the input signal between both drivers when utilizing a single entry cable, allowing for connection to either side. Additionally, the headphones can support both dual and single entry balanced cables.
Nevertheless, the input sockets feature an extended plastic tunnel that serves to protect the plug from unintentional bending; however, this design also restricts the diameter, making it challenging to locate aftermarket plugs that are compatible.
Given that the standard version of the Grell OAE1 is supplied with only one single-ended cable, finding a suitable balanced cable may prove difficult due to this diameter constraint. Therefore, it would be prudent for Drop and Grell Audio to consider offering the original balanced cable that was part of the Signature model bundle.
Except for the cable you only get a 6.35mm plug adapter.

Audio stuff
The headphone features a nominal impedance of 38Ω and a sensitivity of 106dB/Vrms, making it easy to drive without the requirement for specialized amplification. My primary usage has been with the FiiO M23, the iBasso DX180 and the Aune S9C Pro, utilizing the balanced cable from the Signature version.
The Grell OAE1 delivers an astonishing level of bass that may be difficult to comprehend upon initial listening. It requires a brief period to acclimate and fully grasp the auditory experience. The sub-bass extension is remarkable for an open-back headphone, particularly one at such an affordable price point. It is challenging to identify another open headphone that can reproduce frequencies as low as 20Hz with such fidelity. Axel Grell has achieved a tuning that simulates the sensation of having subwoofers positioned near the ears while maintaining impressive clarity in both the midrange and treble frequencies.
The bass is accentuated, deviating from a neutral response, which is unexpected given the designer's background with the HD800. However, this emphasis is not so pronounced as to reach excessive levels that would compromise tonal accuracy. While it is accurate to say that the Grell OAE1 does not offer the most tonally precise low-end, its exuberantly tuned bass creates an engaging and enjoyable listening experience. It is capable of handling classical and acoustic genres, provided one is willing to overlook its lack of neutrality and embrace its more relaxed character. Personally, it may not be my preferred choice for classical music, but it excels with a wide range of other genres, particularly modern electronic and trance music.
In terms of technical performance, the Grell OAE1 generally exceeds average standards. The bass is tight and well-controlled, free from noticeable echo or reverberation, while also being highly impactful and dynamic. It features rich textures and demonstrates quick response times, along with commendable definition and layering. However, it struggles with complex and dense bass lines, where it tends to become one-dimensional, slightly blurred, and somewhat bloated.

More Audio stuff
The Grell OAE1 excels in maintaining an impressive balance and presence in both the mid-range and treble, even with its pronounced low-end. The bass is well-defined, ensuring it does not overshadow or interfere with the mid-range, which is allowed to express itself with clarity and remarkable resolution for its category. The overall tuning is notably balanced, providing satisfactory tonal precision and a natural timbre. The OAE1 is both musical and engaging, offering a rich harmonic variety that connects the listener to the music, effectively reproducing both vocal and instrumental performances.
The mid-range stands out as the headphone's most compelling feature, and in my opinion, it presents a more appealing and balanced sound than the renowned Sennheiser HD650, despite its emphasis on the upper mid-range. Axel Grell appears to have achieved a more refined and sophisticated tuning with the OAE1, resulting in a sound that feels more lifelike and realistic, while minimizing listener fatigue.
The treble is bright and lively, serving to balance the pronounced low-end and prevent an overly warm or dark sound profile. It possesses a brightness that is neither harsh nor piercing, and it resolves adequately for its category, though it may not be perceived as particularly spectacular or brilliant. The Grell OAE1 can be somewhat unforgiving with lower-quality recordings, particularly when paired with bright sources.
A notable drawback regarding the treble is its occasionally unnatural and metallic timbre, which can sound somewhat artificial at times. There is a degree of sterility and dryness, coupled with mildly suppressed overtones and a relative lack of harmonic richness. However, the perceived effects can vary significantly depending on the music and recording quality; for instance, classical music may not be as satisfying, while listeners of electronic music may find little to complain about.
The soundstage
The soundstage presents a varied experience, as it does not create the impression of the OAE1 resembling speakers positioned in front of the listener, contrary to its claims. It does not exhibit a greater expansiveness or holographic quality than most headphones and is notably less wide and immersive than the Sennheiser HD800. Nevertheless, it successfully delivers impressive spatiality with a pronounced central image that appears to emanate from a location outside the listener's head. While the Grell OAE1 may not provide extraordinary expansiveness, it offers a remarkably spacious and open sound within its confines, boasting class-leading depth layering and positioning, even when compared to significantly pricier headphones.

Conclusion
The Drop + Grell OAE1 represents a scientific endeavor by a renowned acoustic engineer, resulting in a headphone that, while very good, may not cater to all preferences. It may not excel in rigorous critical listening and does not fully deliver on its promised speaker-like attributes. However, it does provide an unprecedented sense of spatiality and features a deep bass response that is emphasized yet maintains a balanced overall tuning.
The bass performance is impressive for an open-back headphone, and the tuning approach is vibrant and enjoyable, making it particularly well-suited for casual listening without sacrificing sound quality. The newly released standard version has improved upon the comfort issues found in the Signature model and is offered at a more accessible price point. While the Drop + Grell OAE1 may not resonate with everyone, it is likely to cultivate a dedicated following among enthusiasts.
The review sample was kindly provided free of charge in exchange for an honest review. I don't use affiliate links. The price of the Grell OAE1 is $299 and is exclusively available from Drop. You take advantage of the pre-order discount and get them for $249.
Disclaimer: For various Google indexing reasons, parts of this review may have been processed with an automatic paragraph rewriting tool. However it reads exactly the same as the original content that is available in my website.
Last edited:
J
jamesjames
Thanks for the report. Will these phones accept single entry balanced cables, in the same way for example that the MySphere does?

Ichos
Thank you. It accepts single entry balanced cables, like the one that was included in the signature edition. You can also use aftermarket cables as long as you can find one with a plug that fits the narrow socket of the headphone.
Trinkle
100+ Head-Fier
Pros: Probably the best soundstage for the money
Most effective bass I have ever heard including HE-1 , HE1000SE
Detailed and clear for the money
Nice packaging and portable
Most effective bass I have ever heard including HE-1 , HE1000SE
Detailed and clear for the money
Nice packaging and portable
Cons: Sometimes voices seem incomplete and weak
Cannot compete with big boys in terms of soundstage and detail
Somewhat uncomfortable for tall/wide heads
Cannot compete with big boys in terms of soundstage and detail
Somewhat uncomfortable for tall/wide heads
My unit arrived. Listened today for a few hours and listening as I am writing. I may not be able to point to every point but will write things that stood out to me so far.
Ran on Topping G5.
Comfort.
Even the HE-1 would be useless if it were not comfortable. I understand it can be very comfortable for smaller heads but it is not for those with big or say long heads. I am 6 feet 2 inches, I do not have a wide head but moderately tall one. Even at its max size it puts pressure on the center of the head. Unlike the Sennheiser phones which try to put pressure on two points. I got pretty angry with such a flaw. But then I realized I could reduce the pressure by putting two small tissue papers on the sides to distribute the pressure and I also think as I wore it for a while it kind of loosened or I got used to it. The other thing is the PU leather kinda feel sticky if you have a shiny bald spot
, but with time or say with the use of tissue paper I learned to handle the pressure, but given I did not feel this with HD 660S , 560S, 800S , HE-1 , HE100SE but with this one, says not a lot of thought was given to the comfort. Clamp force may feel a bit high but still felt less than the un-stretched 660S, so that is okay.
Axel Grell mentioned comfort pads will be available sometime in the future.
Soundstage.
It is quite big but not as big as HD800S, or HE1000SE. Listening side by side with HD 660S it felt bigger, I think its bigger than HE-1 too but not as deep as HE-1. Although the soundstage is not as big as HD800S, if you draw your imaginary instruments and singers with HD 800S their positions will seem weird and not make sense, some too close , some too far away but with the OAE-1 it kind of makes sense. But it is smaller than HD 800S and has less airy feeling than it. Even though soundstage felt big I did not mix up its sound with reality, which I did once in a while with HD 800S. I think soundstage and imaging only does not confuse you, the sound has to be detailed enough to make you think the sound may be coming from outside. The sound is surely not as detailed .... more on this later. Once I felt a particular sound was coming from my side a little bit in the back, but the sound itself did not match sounds in the real world much so won't say it was an aha moment. For me even though soundstage imaging is way better than what the price may suggest, it is not anything drastically different as we might expect from the positioning of the drivers. But then again it is probably the third biggest soundstage I have heard next to HE1000Se, and HD 800S.
Bass.
This made me a believer in Axel Grell's theory. Although I noticed bass in multiple tracks, when I heard the drum in Frozen by Madonna in the long instrumental part, I felt the bass hit my face, forehead and neck. I felt the vibration just like Axel said we would !!!!
Starts at 3:10 https://tidal.com/browse/track/1669855?u
I am very sensitive to bloated bass, this did not seem to be bloated or muddy.
Detail retrieval and clarity
If you listen slightly carefully you will feel it has more air and clarity than HD 660S, but its not like when you move to HD 800S and you feel "my whole music listening was a lie" and "how could I bear the 660S" no its not like that but still its clearer.
But still it lags behind 660S, (also HD800S and HE-1 ) in some areas. For example in the song "The way we were" where Barbra Streisand hums in the beginning, all 660S, HD800S HE-1, they all sound so sweet and full (660S is like warm bread, HD 800S is like butter on bread, HE-1 is like honey on bread and butter). But with OAE-1 her humming seems uneven as if some portions of the frequencies are subdued.
https://tidal.com/browse/track/1317337?u
In multiple songs some voices seem somewhat subdued but not muffled. As if weak and some parts missing, but not veiled by something. May be I need to eq that part.
The headphone handles excessive volume really well, so I assume it will respond to EQ well too.
The beep, beeps at the start of the song sweet surrender by Sarah McLachlan also had this issue, they seemed more broken than HD 800S or HE1000SE , speaking from memory here btw https://tidal.com/browse/track/225534413?u
With Cello music you often can feel the bow slide on the strings with the HD 800S, not so much with this one, so some smoothness is missing in that region. But hey remember its $350.
I did not feel any treble spike though.
Portability and Usage
The case is super portable , and solid enough to protect the headphone. Can easily slide in my backpack.
Summary
It is a very good headphone for $350 but cannot compete with the big boys like HD 800S and HE1000SE except for the bass. It is an unfair comparison but somehow we unfairly set our expectations too high given Axel Grell's legacy. If this did beat out HD 800S and HE1000SE in every aspect, Sennheiser and Hifiman would go bankrupt lol. But it surely beats out the pricier HD 660S in my book and it surely beats every headphone I have heard out there in terms of bass. It proves that the concept works as this is probably the maximum amount of soundstage anyone achieved with a 40 mm driver that is not even a ring driver emitting planar waves. It also proves that you can produce clean bass and make your body feel it which none of the headphones I tried 660S, HD 800S, HE100SE or HE-1 did for me. But I felt this with only one song as I mentioned.
Will I keep it ?
Overall I like the sound better than the headphone I am currently using 660S, it sounds clearer and bigger, it has this unique bass which I might miss if I return it. I can fix the comfort issue with tissue paper or some leather and glue and official comfort pads will be available in the future. I need to stop myself from itching till i get the next Sennheiser headphone (hopefully God willing). I believe given it has an Axel Grell signature it will have a good resale value. So I guess I will keep it.
Although I do not feel everything was perfect I think the two concepts regarding the orientation and bass have been proven at least to me.
Ran on Topping G5.
Comfort.
Even the HE-1 would be useless if it were not comfortable. I understand it can be very comfortable for smaller heads but it is not for those with big or say long heads. I am 6 feet 2 inches, I do not have a wide head but moderately tall one. Even at its max size it puts pressure on the center of the head. Unlike the Sennheiser phones which try to put pressure on two points. I got pretty angry with such a flaw. But then I realized I could reduce the pressure by putting two small tissue papers on the sides to distribute the pressure and I also think as I wore it for a while it kind of loosened or I got used to it. The other thing is the PU leather kinda feel sticky if you have a shiny bald spot

Axel Grell mentioned comfort pads will be available sometime in the future.
Soundstage.
It is quite big but not as big as HD800S, or HE1000SE. Listening side by side with HD 660S it felt bigger, I think its bigger than HE-1 too but not as deep as HE-1. Although the soundstage is not as big as HD800S, if you draw your imaginary instruments and singers with HD 800S their positions will seem weird and not make sense, some too close , some too far away but with the OAE-1 it kind of makes sense. But it is smaller than HD 800S and has less airy feeling than it. Even though soundstage felt big I did not mix up its sound with reality, which I did once in a while with HD 800S. I think soundstage and imaging only does not confuse you, the sound has to be detailed enough to make you think the sound may be coming from outside. The sound is surely not as detailed .... more on this later. Once I felt a particular sound was coming from my side a little bit in the back, but the sound itself did not match sounds in the real world much so won't say it was an aha moment. For me even though soundstage imaging is way better than what the price may suggest, it is not anything drastically different as we might expect from the positioning of the drivers. But then again it is probably the third biggest soundstage I have heard next to HE1000Se, and HD 800S.
Bass.
This made me a believer in Axel Grell's theory. Although I noticed bass in multiple tracks, when I heard the drum in Frozen by Madonna in the long instrumental part, I felt the bass hit my face, forehead and neck. I felt the vibration just like Axel said we would !!!!
Starts at 3:10 https://tidal.com/browse/track/1669855?u
I am very sensitive to bloated bass, this did not seem to be bloated or muddy.
Detail retrieval and clarity
If you listen slightly carefully you will feel it has more air and clarity than HD 660S, but its not like when you move to HD 800S and you feel "my whole music listening was a lie" and "how could I bear the 660S" no its not like that but still its clearer.
But still it lags behind 660S, (also HD800S and HE-1 ) in some areas. For example in the song "The way we were" where Barbra Streisand hums in the beginning, all 660S, HD800S HE-1, they all sound so sweet and full (660S is like warm bread, HD 800S is like butter on bread, HE-1 is like honey on bread and butter). But with OAE-1 her humming seems uneven as if some portions of the frequencies are subdued.
https://tidal.com/browse/track/1317337?u
In multiple songs some voices seem somewhat subdued but not muffled. As if weak and some parts missing, but not veiled by something. May be I need to eq that part.
The headphone handles excessive volume really well, so I assume it will respond to EQ well too.
The beep, beeps at the start of the song sweet surrender by Sarah McLachlan also had this issue, they seemed more broken than HD 800S or HE1000SE , speaking from memory here btw https://tidal.com/browse/track/225534413?u
With Cello music you often can feel the bow slide on the strings with the HD 800S, not so much with this one, so some smoothness is missing in that region. But hey remember its $350.
I did not feel any treble spike though.
Portability and Usage
The case is super portable , and solid enough to protect the headphone. Can easily slide in my backpack.
Summary
It is a very good headphone for $350 but cannot compete with the big boys like HD 800S and HE1000SE except for the bass. It is an unfair comparison but somehow we unfairly set our expectations too high given Axel Grell's legacy. If this did beat out HD 800S and HE1000SE in every aspect, Sennheiser and Hifiman would go bankrupt lol. But it surely beats out the pricier HD 660S in my book and it surely beats every headphone I have heard out there in terms of bass. It proves that the concept works as this is probably the maximum amount of soundstage anyone achieved with a 40 mm driver that is not even a ring driver emitting planar waves. It also proves that you can produce clean bass and make your body feel it which none of the headphones I tried 660S, HD 800S, HE100SE or HE-1 did for me. But I felt this with only one song as I mentioned.
Will I keep it ?
Overall I like the sound better than the headphone I am currently using 660S, it sounds clearer and bigger, it has this unique bass which I might miss if I return it. I can fix the comfort issue with tissue paper or some leather and glue and official comfort pads will be available in the future. I need to stop myself from itching till i get the next Sennheiser headphone (hopefully God willing). I believe given it has an Axel Grell signature it will have a good resale value. So I guess I will keep it.
Although I do not feel everything was perfect I think the two concepts regarding the orientation and bass have been proven at least to me.
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Evshrug
Headphoneus Supremus
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.
+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.
-Lower male vocals a bit muted, but not dry or flat.
-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.
-Lower male vocals a bit muted, but not dry or flat.
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
.
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 enough range that I can fit two fingers between my head and the headband, adjusts 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. In fact, un-clipping the headband would allow quick loosening of the clamping pressure (click here to see how). 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.
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.
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


![]() |
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 enough range that I can fit two fingers between my head and the headband, adjusts 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. In fact, un-clipping the headband would allow quick loosening of the clamping pressure (click here to see how). 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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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, unusually strong sub bass for an open headphone, 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.
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
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
Headphone Comparisons:
Edit 5-26-24:
Today, I’m choosing to compare the grellphone to the HD 650, because they are closest related and the HD 650 (and HD 6XX) is such a common standard for comparison, and also the HD 800, a headphone noted for big soundstage and insight into recordings. I want to emphasize; I think you could listen long enough to any of these for brain burn-in and end up enjoying any of them, but certain strengths remain. For fairness sake, I’m using stock 6.5mm cables with all headphones, running off my 0 Ω output impedance Cavalli Liquid Carbon amp, and using my HDV 820’s XLR output as a DAC, with a really short usb cable going to my iPad Air on battery power.
Classic rock: “Stairway to Heaven” by Led Zepplin.
I think this track is actually a strong point for the HD 800. This is especially evident in the easily picked out reverb from off stage, and I think the percussive cymbals sound more realistic here. The HD 650 takes a bit more concentration to pick up on the soundstage and it sounds more intimate, a tighter stage, but pretty good. The OAE1 has perception of the reverb almost as well as the HD 800, but the rolling snare drum impacts seem a bit more recessed, making me want to turn up the volume a bit more. Switching back to the HD 800 after the OAE1 sounds more splashy and brash though.
Alternative Rock: “Undisclosed Desires” by Muse
The HD 800 here emphasizes the violin plucks, and has very good “buzz” texture. The texture is also very good on the HD 650, but there’s a drop more bass and the plucked violins take a step back in emphasis, changing the feeling of the song a bit. The OAE 1 vocals at 51 seconds in takes a step into the audience after the HD 650, less intimate, but overall I think it takes the crown for this song. The bass is emphasized more than on the other headphones, the bass guitar flourishes are punchy with impactful leading edge, the synths swim around the head, and the “call and response” bass event at the end of this song is just so much more significant here than on the other headphones: it throbs rather than murmurs. The OAE1 both more chill than the HD 800, it makes the HD 650 sound a bit rolled off on both ends of the frequency spectrum, and after a second of adjustment sounds very rich.
Alternative (2019): “bad guy” by Billie Eilish
This whole album is really well mastered, very clear, and on the HD 800 it sounds like Billie is singing right up against my ears. Her little forced exhales, overlapping vocal takes, and the electronic chirps are just as evident on the HD 650 though. The OAE1 stands out as the most different here, with the intimate multi personality vocals sounding the same but the electric bass and electric synth (and the… muted bass drum?) sounding stronger, and the rest at 2:29 hitting back all the more stronger when slammed by the bass, and the tight bass doesn’t mask the cool “thock!” sound popping off down the hall.
Trip Hop: “Angel” by Massive Attack
The HD 650 comes in right away with the bass guitar rumbling in, Andy Horace’s voice sounds so velvety smooth, and honestly this is a balanced take that feels very familiar to me after all these years. The cymbals sound distorted and weird though, and when the electric guitar kicks in at 2:23 things sound a little hectic, busy, and furtive. Putting on the HD 800, there is much less “wall of sound” and it’s a little more relaxed to hear each instrument playing, and it’s more obvious that the metronomic percussion isn’t cymbals but actually drums with a digital “swimming” effect applied to them (the cymbals come in clean at near 2 minutes, kinda stealing the show as far as emphasis goes), and I think this headphone is good for percussive fans. The bass is tight like two large marble balls making impact, but restrained. The OAE1… the bass is still tight, but it’s so much bigger! The distorted drums starting at 1:39 still sound like drums, and I’m aware of the cymbals, vocals are a little less intimate than the HD 650, but again at 2:23 the sound doesn’t devolve into confusion despite how many instruments are playing at once. I might choose to EQ up Horace’s vocals a bit, but the threat of this song is emotionally portrayed with strength. I also like how the final beats, when played alone at the end of this song, show an abrupt end of decay.
Classical: The Planets Suite, Op. 32: IV Jupiter by Gustav Holst, performed by Vladimir Jurowski & London Philharmonic Orchestra
Let’s start this track with the OAE1, eh? There are MANY different orchestras that have performed this, but I chose this one because it was newly featured in Apple Music’s Spatial Audio showcase. Before hearing any other headphone, I’m hearing a good balance between harp and violin, big drums and brass, and the Spatial Audio is doing a good job of laying out the musicians in front of me. I especially am enjoying a moment near the end at 6:30, where various flutes flourish and things get a little more magical, before a big drum roll builds up and releases a nice climax. How’s the HD 650 by comparison? It feels lighter, that’ll be the lower bass presence and more forward lower mids. It’s not doing the sense of Spatial Audio as well though… the instruments seem lined up straight between my left and right ear. There’s some sense of the spatial effect, but the imaging is just more hazy. It’s also a bit harder to pick out the harp among the other instruments… it’s there, just not as well separated. Emotionally, I don’t think this would put me on the edge of my seat or send shivers up my spine, but the brass horns do tizz a little bit. The violins near that 6:30 end sequence are a bit more in line with the flutes and stuff, but I was less impressed by the drum roll. Sometimes plain is good, but this was a less exciting listen than on the OAE1. Now, the HD 800 is the ace of classical, right? Well, it certainly does make me perk up a bit now! The spatial perception is back, the brass horns are forward and have strong texture but doesn’t seem to stick out like a sore thumb among all the other “air” happening. The harp feels more visceral. How’s that point near the end? Well, the flutes and violins are all cool, the drums build up less of a crescendo but it’s still an exciting finish because of how energetic everyone is playing. What’s it like to switch back to the OAE1 again? Yeah, it sounds about as open as the HD 800, also exciting, but again the drums just thunder more and fill in that end of the spectrum more.
In conclusion, I’d like to reiterate that all three of these are great headphones. It does seem like the lower mids are the HD 650’s greatest strength but overall it’s more mild sense of air and sub bass (and less clear sense of separation) don’t give me the fizz. The HD 800 has fantastic separation and clears up the confusion, as well as having more clear imaging and responds well to Spatial Audio or Headphone mastered music, really tight attack, but it’s airy flavor gives me the fizz but the bass impact is undeniably lighter. The OAE1 can rip that bass and sub bass, giving me the fizz in a different way, and also shares that separation and soundstage, though lower male vocals and notes around those frequencies seem more laid back. The lower mids do not seem dry and dull to me though, just a bit quieter, so a bit of EQ might be enough to help, or so far simply turning up the volume a bit fills that in for me, and the OAE1 handles higher volumes well. On pure technical performance, the OAE1 is punching above its price, and subjectively I find it a fun emotional headphone.
CONSOLIDATING NOTES, WILL EDIT
Compare & Contrast with popular reference headphones
Headphone Comparisons:
Edit 5-26-24:
Today, I’m choosing to compare the grellphone to the HD 650, because they are closest related and the HD 650 (and HD 6XX) is such a common standard for comparison, and also the HD 800, a headphone noted for big soundstage and insight into recordings. I want to emphasize; I think you could listen long enough to any of these for brain burn-in and end up enjoying any of them, but certain strengths remain. For fairness sake, I’m using stock 6.5mm cables with all headphones, running off my 0 Ω output impedance Cavalli Liquid Carbon amp, and using my HDV 820’s XLR output as a DAC, with a really short usb cable going to my iPad Air on battery power.
Classic rock: “Stairway to Heaven” by Led Zepplin.
I think this track is actually a strong point for the HD 800. This is especially evident in the easily picked out reverb from off stage, and I think the percussive cymbals sound more realistic here. The HD 650 takes a bit more concentration to pick up on the soundstage and it sounds more intimate, a tighter stage, but pretty good. The OAE1 has perception of the reverb almost as well as the HD 800, but the rolling snare drum impacts seem a bit more recessed, making me want to turn up the volume a bit more. Switching back to the HD 800 after the OAE1 sounds more splashy and brash though.
Alternative Rock: “Undisclosed Desires” by Muse
The HD 800 here emphasizes the violin plucks, and has very good “buzz” texture. The texture is also very good on the HD 650, but there’s a drop more bass and the plucked violins take a step back in emphasis, changing the feeling of the song a bit. The OAE 1 vocals at 51 seconds in takes a step into the audience after the HD 650, less intimate, but overall I think it takes the crown for this song. The bass is emphasized more than on the other headphones, the bass guitar flourishes are punchy with impactful leading edge, the synths swim around the head, and the “call and response” bass event at the end of this song is just so much more significant here than on the other headphones: it throbs rather than murmurs. The OAE1 both more chill than the HD 800, it makes the HD 650 sound a bit rolled off on both ends of the frequency spectrum, and after a second of adjustment sounds very rich.
Alternative (2019): “bad guy” by Billie Eilish
This whole album is really well mastered, very clear, and on the HD 800 it sounds like Billie is singing right up against my ears. Her little forced exhales, overlapping vocal takes, and the electronic chirps are just as evident on the HD 650 though. The OAE1 stands out as the most different here, with the intimate multi personality vocals sounding the same but the electric bass and electric synth (and the… muted bass drum?) sounding stronger, and the rest at 2:29 hitting back all the more stronger when slammed by the bass, and the tight bass doesn’t mask the cool “thock!” sound popping off down the hall.
Trip Hop: “Angel” by Massive Attack
The HD 650 comes in right away with the bass guitar rumbling in, Andy Horace’s voice sounds so velvety smooth, and honestly this is a balanced take that feels very familiar to me after all these years. The cymbals sound distorted and weird though, and when the electric guitar kicks in at 2:23 things sound a little hectic, busy, and furtive. Putting on the HD 800, there is much less “wall of sound” and it’s a little more relaxed to hear each instrument playing, and it’s more obvious that the metronomic percussion isn’t cymbals but actually drums with a digital “swimming” effect applied to them (the cymbals come in clean at near 2 minutes, kinda stealing the show as far as emphasis goes), and I think this headphone is good for percussive fans. The bass is tight like two large marble balls making impact, but restrained. The OAE1… the bass is still tight, but it’s so much bigger! The distorted drums starting at 1:39 still sound like drums, and I’m aware of the cymbals, vocals are a little less intimate than the HD 650, but again at 2:23 the sound doesn’t devolve into confusion despite how many instruments are playing at once. I might choose to EQ up Horace’s vocals a bit, but the threat of this song is emotionally portrayed with strength. I also like how the final beats, when played alone at the end of this song, show an abrupt end of decay.
Classical: The Planets Suite, Op. 32: IV Jupiter by Gustav Holst, performed by Vladimir Jurowski & London Philharmonic Orchestra
Let’s start this track with the OAE1, eh? There are MANY different orchestras that have performed this, but I chose this one because it was newly featured in Apple Music’s Spatial Audio showcase. Before hearing any other headphone, I’m hearing a good balance between harp and violin, big drums and brass, and the Spatial Audio is doing a good job of laying out the musicians in front of me. I especially am enjoying a moment near the end at 6:30, where various flutes flourish and things get a little more magical, before a big drum roll builds up and releases a nice climax. How’s the HD 650 by comparison? It feels lighter, that’ll be the lower bass presence and more forward lower mids. It’s not doing the sense of Spatial Audio as well though… the instruments seem lined up straight between my left and right ear. There’s some sense of the spatial effect, but the imaging is just more hazy. It’s also a bit harder to pick out the harp among the other instruments… it’s there, just not as well separated. Emotionally, I don’t think this would put me on the edge of my seat or send shivers up my spine, but the brass horns do tizz a little bit. The violins near that 6:30 end sequence are a bit more in line with the flutes and stuff, but I was less impressed by the drum roll. Sometimes plain is good, but this was a less exciting listen than on the OAE1. Now, the HD 800 is the ace of classical, right? Well, it certainly does make me perk up a bit now! The spatial perception is back, the brass horns are forward and have strong texture but doesn’t seem to stick out like a sore thumb among all the other “air” happening. The harp feels more visceral. How’s that point near the end? Well, the flutes and violins are all cool, the drums build up less of a crescendo but it’s still an exciting finish because of how energetic everyone is playing. What’s it like to switch back to the OAE1 again? Yeah, it sounds about as open as the HD 800, also exciting, but again the drums just thunder more and fill in that end of the spectrum more.
In conclusion, I’d like to reiterate that all three of these are great headphones. It does seem like the lower mids are the HD 650’s greatest strength but overall it’s more mild sense of air and sub bass (and less clear sense of separation) don’t give me the fizz. The HD 800 has fantastic separation and clears up the confusion, as well as having more clear imaging and responds well to Spatial Audio or Headphone mastered music, really tight attack, but it’s airy flavor gives me the fizz but the bass impact is undeniably lighter. The OAE1 can rip that bass and sub bass, giving me the fizz in a different way, and also shares that separation and soundstage, though lower male vocals and notes around those frequencies seem more laid back. The lower mids do not seem dry and dull to me though, just a bit quieter, so a bit of EQ might be enough to help, or so far simply turning up the volume a bit fills that in for me, and the OAE1 handles higher volumes well. On pure technical performance, the OAE1 is punching above its price, and subjectively I find it a fun emotional headphone.
“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.
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
Some tips on loosening the caliper/clamping pressure with a spring in the headband: https://www.head-fi.org/threads/drop-grell-oae1.967413/post-18210418
Looks like there may be some modding opportunities for “big brained” people if they want to try.
Looks like there may be some modding opportunities for “big brained” people if they want to try.

ericp10
I won't say much as I just got mine today and I believe a good burn-in is needed. But out of the box, I'm not disappointed at all. For an opened headphone, the bass/sub-bass is lovely! It loves Miles and Coltrane's horns on "So What." A good spacious sound and it can dig down for the details I'm finding. The sound is neither too warm nor too cool. Male and female vocals are lovely (but especially male). That's all I have right now.