The Grell Audio OAE2 is a dynamic driver open-back headphone launched in March 2026. It uses a 40mm dynamic driver that is heavily angled inside the cup to create a more realistic soundstage and imaging experience. The OAE2 is targeted at studio professionals and audiophiles alike, and launched at $599 / €499 / £499 (European VAT included)
The Audeze MM-100 is a planar magnetic open-back headphone. It uses a 90mm planar magnetic driver with Audeze Fluxor magnets and Fazor waveguides. The MM-100 typically costs a bit less than the OAE2, depending on your location: 399 USD / €499 (VAT included).
GRELL OAE2 SPECIFICATIONS
- Type: open-back full size
- Heavily angled drivers, positioned in the front of the cup
- Driver: 40 mm dynamic
- Diaphragm: bio-cellulose
- Impedance: 38 Ohms
- Sensitivity: 100 dB
- Frequency Response: 12 Hz – 34 kHz
- THD: 0.05% (1 kHz, 100 dB)
- Pads: Velour
- Cable: 2 x 1.8 m single-sided, material: silver plated OFC.
- Cable connector 2.5 mm 4-pole on headphones
- Cable termination: 4.4 mm balanced jack or 3.5 mm with 6.35 mm adapter
- Transport case included
- Fully modular and serviceable
- Weight: 378 g
Grell Audio: Products
AUDEZE MM-100 SPECIFICATIONS
- Type: Over-ear, open-back
- Transducer type: Planar Magnetic
- Magnetic structure: Fluxor™ magnet array
- Phase management: Fazor™
- Magnet type: Neodymium N50
- Diaphragm type: Ultra-Thin Uniforce™
- Transducer size: 90 mm
- Impedance: 18 ohms
- Sensitivity: 98 dB/1mW (at Drum Reference Point)
- Maximum SPL >120dB
- Frequency response: 20Hz – 25kHz
- THD <0.1% @ 100 dB SPL, 1kHz
- Max power handling: 5W RMS
- Min recommended power >100mW
- Recommended power level >250mW
- Cable: 2.5m (8.2ft) Single ended TRRS to 1/4″ TRS
- Warranty: 1 year
- Weight: 475g
Amazon: Audeze MM-100
BUILD AND DESIGN
The OAE2 features a padded headband, while the MM-100 uses a headband strap, which some may find more comfortable. The OAE2 uses velour pads with standard, rather stiff foam that breathe very well, while the MM-100 has pleather pads with softer memory foam.
The OAE2 has proprietary, detachable ear pads. However, they aren’t easily replaced by third-party pads because the attachment mechanism is so unique.
The MM-100 has glued-on pads with a double-sided tape ring, typical of Audeze and identical to the MM-500. This means you can use third-party pads, but you have to attach them with double-sided tape. MM-100 and MM-500 pads are the same dimensions. A video of the replacement process can be found here:
Youtube: Replace MM-100 and MM-500 pads.
The OAE2 is built as a modular design with all parts being relatively easily replaceable, and the end user is intended to be able to service them to a large extent. The MM-100 has no special focus on this. The OAE2 comes with a two-year warranty, while the MM-100 offers only one year.
Personally, I find both to be comfortable to wear, but neither ranks among my favourites in the comfort department. The headband of the MM-100 is more comfortable, while the velour pads on the OAE2 breathes much better than the MM-100 pleather.
As always, comfort preferences are individual; which you find more comfortable will depend on the shape of your head and other preferences.
LISTENING COMPARISONS
Associated equipment:
- Amplifier: Topping A90
- DAC: RME ADI-2 DAC FS
Outlaws by Bill Frisell
The OAE2 delivers a very spacious and balanced presentation, with tight and tactile bass. The MM-100 has less instrument separation and the imaging is wider but more left-right with less depth. However, even though the overall tonal balance is similar, it sounds smoother and somewhat more relaxed in a pleasant way.
Sujet Tabou by Renaudin and Cahours
A very dynamic piece with classical guitar, percussion, and some vocals. The OAE2 is cleaner and more on point; it is more precise and with better imaging. The MM-100 is more diffuse but still very dynamic and detailed.
The Hidden Camera by Photek
The MM-100 sounds excellent, well balanced with very controlled, detailed bass and great instrument separation. The OAE2 again has better imaging, with instruments placed more in front and less side to side. It is tighter, crisper, and more focused, but also drier and crisper in tone.
Re-Melt by Tord Gustavsen Trio
The OAE2 is very tight and precise with specific instrument placement. The MM-100 sounds more liquid and less tight, but equally detailed.
Love Your Grace by Vega Trails
The MM-100 sounds wider and more dreamy. The OAE2 presents instruments more narrowly and more in front of you, although they are still not truly “outside your head”. The tonal balance is quite similar between the headphones, though.
How Deep by John Scofield
Again, very similar tonal balance. The MM-100 is a bit wider and more diffuse sounding, but also more liquid and smooth. The OAE2 is more focused.
Eye of the Day by Marta del Grandi
The OAE2 is tight and crisp, slightly dry, with upfront and textured vocals that sound very nice. The MM-100 has slightly darker, warmer, more liquid vocals and a wider soundstage.
Dancing in the Dark by Jørgen Dahl Moe
A fantastic version of this classic Springsteen song. The MM-100 is wonderful, with a nice sense of liquidity and a delicate touch to the presentation. The OAE2 offers brighter, drier vocals; it sounds a bit more aggressive and crisper. There is lots of detail, but the MM-100 offers a more nuanced feel.
As Before by Olga Konkova
The OAE2 offers a tight and punchy cajón drum, quite delicate and smooth piano and vocals with nice texture. The MM-100, surprisingly, has a significantly leaner drum delivery, the piano is more upfront and less smooth, and the vocals are liquid and delicate. The OAE2 is my favourite here.
Limit to Your Love by James Blake
Here too, the OAE2 sounds better. The vocals have a more upfront and natural timbre, and the bass is notably better. The MM-100 sounds darker and a bit more “boxed in” when compared directly, albeit perfectly fine on its own.
Vicarious by Tool
The MM-100 sounds quite enveloping and well balanced, detailed without becoming sharp or dry. The OAE2 has better separation and dynamics, though it can sound a bit shouty in the busiest parts.
Like Suicide by Soundgarden
The OAE2 handles this track like a champ, with excellent dynamics and tonality. The MM-100 sounds good too, but a bit sharp and uneven. This is a difficult track to get right, and the MM-100 does better than most, just not as well as the OAE2.
Impedans by Erlend Apneseth Trio
The MM-100 is fantastic with this album. It is so immersive and mesmerising, dynamic and spacious, with an extra “it factor”. The OAE2 sounds good, but something is missing when compared directly to the MM-100; the magic is not as present.
Largo by Vega Trails
Here too, the OAE2 does nothing wrong. It is neutral and precise. Still, the MM-100 offers something extra, something hard to describe. It is also quite neutral and precise, but at the same time it offers more presence, a richer, more organic experience. To me it is more appealing, though others may feel differently.
Spontaneous Compositorius by Thomas Agergard
The MM-100 offers a rich saxophone, the bright percussion is clean and not overly sharp, and the bass is detailed and rather politely present compared to many other headphones. The OAE2 is quite similar, with the treble a tad sharper and the bass a bit stronger.
WRAPPING IT UP
Sound Signature
Both the Grell Audio OAE2 and the Audeze MM-100 offer a neutral tuning with good balance between bass, mid-range, and treble. They are both clearly made with professional use in mind.
Treble
Both headphones have nice, clean treble; the OAE2 tends to be slightly more prominent, but neither is overly sharp or piercing.
Midrange
The mid-range is also relatively similar, but the OAE2 often comes across as a bit brighter, depending on the track.
Bass
Bass quantity is also relatively similar; more often than not, the OAE2 has a bit more.
Soundstage and Imaging
Here they differ more. The MM-100 is wider and more left-right, while the OAE2 is narrower but with more depth. The instruments feel as though they are placed slightly in front of you, or at least in front of the center of your head.
Detail, Dynamics, and Timbre
In terms of detail retrieval they are fairly comparable, but I find the OAE2 to be generally more articulate, with detail a bit more apparent, while the MM-100 is a tad more laid back and smoother – a bit more ethereal.
The OAE2 has strong dynamics, but the MM-100 is not far behind.
When it comes to timbre, they are both similar and different. The tonality is broadly speaking quite similar, but there are variations; in the mid-range, for instance, the MM-100 often sounds a bit darker, depending on the track.
Mostly I feel that the Grell OAE2 is more coherent and “correct”, with the MM-100 close behind but deviating a bit more from neutrality on certain tracks. On the other hand, perhaps because of this, the MM-100 can on certain tracks bring something extra, an intangible quality that I find difficult to describe precisely.
The MM-100 can give a more immersive listening experience, a small dose of “magic sauce” that makes a lot of difference on some tracks. There is nothing wrong with the OAE2, but it can sometimes sound too correct, perhaps too neutral.
CONCLUSION
Both the Grell Audio OAE2 and the Audeze MM-100 are excellent headphones aimed at professional use, and both offer a neutral, well-balanced sound that holds up well across a wide range of music.
The OAE2 is the more precise and analytical of the two, with better imaging, stronger dynamics, and a more coherent overall presentation. The MM-100 trades some of that precision for a wider, smoother, and more organic sound that can feel more immersive and engaging on certain tracks.
I can recommend both headphones without hesitation.
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