The Grell OAE2 is a new open-back headphone priced at $599 USD. It is an interesting piece of kit that moves away from the standard headphone blueprint, teasing things like a fully modular build and some fairly unique driver positioning. I have been keen to see if these design choices actually make a functional difference or if they are just there for the sake of being different.
If the name doesn’t ring a bell, Axel Grell is the guy who spent nearly three decades at Sennheiser, heading up the development of legends like the HD 600 and the HD 800 headphones. Having that kind of track record behind a product means we can expect a certain level of technical maturity, but it also raises expectations. Let’s see how the OAE2 turned out.
Disclaimer: This sample was provided by Grell Audio for an honest review. All observations and opinions here are my own, based on my experience with the product.
Grell OAE2
Features
The Grell OAE2 features the largest open baffle on the market, which creates more distance between the driver and your ear. This allows for unrestricted airflow, which avoids that closed-in sensation you sometimes get with traditional designs.
Instead of being parallel to your head, the front-sided transducers are angled to work with your ear’s natural geometry. This helps the treble feel more natural and improves how you perceive space.
Inside, Grell used 40 mm wideband bio-mimetic drivers with a resonance frequency of 40 Hz. That’s quite a bit lower than the 70 Hz you’ll see in most headphones, which helps keep things clean and controlled in the lower frequencies.
I also like that the whole design is modular. Every component is replaceable, so if a part wears out or breaks, you can just swap it out rather than having to replace the entire unit. It’s a solid approach to longevity.
Design & Comfort
When you first pick up the Grell OAE2, the first thing you notice is the build quality. This is an all-metal construction, and it feels seriously premium in the hand. It has that industrial, utilitarian vibe that Axel Grell is known for, but the materials here are top notch. You are getting sturdy aluminium yokes and a stainless steel mesh that covers the earcups. It feels like a proper, durable piece of engineering.
What is really interesting here is the driver placement. The 40mm bio-cellulose drivers are angled quite sharply towards the front. It is part of the Front-Side Sound Field Modulation system, and it gives the inside of the cups a very unique internal geometry. One great thing to mention is that these are built with a modular philosophy, so most parts are user-replaceable. That is a massive win for longevity.
Moving on to comfort, it is a bit of a story of two halves. At about 378 grams, the weight is not an issue at all. The circular earcups are massive, so there is loads of room for your ears, and they are finished in a soft velour. The foam inside is standard rather than memory foam, so it feels a bit firmer than some other headphones in this bracket. The clamp is definitely secure, but the generous swivel helps the cups settle on your face nicely.
The headband is where things might get tricky for some. The padding is fairly firm. If you have a larger head, you might find the adjustment range a bit tight, which can lead to a bit of a hotspot on the top of your head during longer sessions.
One thing I really appreciate is the cable setup. There are 2.5mm ports on both sides, but it is a single-sided cable entry. You just plug it into whichever side works best for your desk layout. It is such a simple, practical feature that more brands should adopt. You get both a 3.5mm and a 4.4mm cable in the box, and they are both about 1.8 metres long. They also include a large, flat carry case.
Sound
Bass
Starting with the bass, this is one of the more impressive aspects of the OAE2, especially for an open-back. There’s genuinely good sub-bass depth here, and you can feel it when a track calls for it. It’s not overblown or pushed forward in the mix, but there’s a slight lift that gives the bass a bit of physicality.
Mid-bass has a nice, meaty kick with a natural sense of weight and decay. It doesn’t come across as loose or resonant inside the earcups, which is important for this type of design. In terms of control, it holds up well. Even with something like James Blake’s “Limit To Your Love”, it doesn’t start to sound slow or lose composure.
Midrange
The midrange strikes a good balance between clarity and body. Notes come through cleanly, but there’s still enough weight behind them to keep things sounding natural.
There is a lift in the upper mids, at around 2–3 kHz. Female vocals benefit the most from this. They come through clearly and have a bit of lift, but stay on the safe side of being too forward. Male vocals aren’t as forward, but they still have enough presence to come through clearly in the mix.
Treble
The lower treble is on the brighter side, but it’s handled in a controlled way. There’s a lift around 5kHz which gives instruments like trumpets more bite and presence. They stand out, but it doesn’t push too far into harshness. OAE2’s upper treble is smooth, yet crisp and airy.
The timbre here is very natural. It’s not what I would call a sparkly treble, but it avoids sounding splashy or artificial. It leans more towards clarity and definition rather than trying to impress with sheer energy.
Soundstage and Technicalities
This is where the Grell OAE2 really stands out. The soundstage is genuinely impressive, with a sense of scale that feels larger than most traditional headphones. It has that open, spacious presentation that gives everything room to breathe.
Detail retrieval is above average. It doesn’t force detail forward, but it’s easy to pick up on smaller nuances in the mix. Combined with the overall balance of warmth and clarity, it comes across as a very engaging and well put together tuning.
Comparisons
Sennheiser HD650
When it comes to the sound, these two are quite different beasts. The Grell OAE2 has a brighter profile overall. Most of you know the HD650 for that warm, relaxed, and very natural signature. It is the kind of headphone you can listen to all day without any fatigue.
The OAE2, on the other hand, really steps things up in terms of mid-range and vocal clarity. When you listen to them side by side, the vocals on the Grell really stand out. However, because it has more energy in the upper mids and lower treble, it is not quite as relaxed as the Sennheiser. If you are sensitive to those areas, you might find it a bit more fatiguing over long sessions.
But where the OAE2 really takes the lead is in the technicalities. The soundstage is even larger than the HD650, the micro-detail retrieval is on another level, and you get much better sub-bass depth and a punchier bass response in general.
Heddphone D1
The Heddphone D1 is a bit more expensive, and it is designed primarily as a studio monitor. That means it is all about accuracy and a linear, neutral response across the board. In comparison, the D1 actually sounds slightly warmer and more relaxed than the OAE2.
The Grell OAE2 is definitely the more engaging and musical of the two. It has more brightness and energy in the lower treble, which makes it feel a bit more alive. Both headphones have outstanding resolution and excellent instrument separation, but I was honestly surprised to find that the detail retrieval on the OAE2 is actually better than it is on the D1.
Choosing between them really comes down to what you want. If you need something for clinical accuracy, the D1 is the way to go. But if you want a more engaging, musical experience with massive scale and detail, the OAE2 is the winner.
Verdict
To wrap things up, I’m genuinely impressed with the Grell OAE2. Axel Grell has clearly moved away from the standard headphone blueprint here to build something with a real sense of purpose. The all-metal build is beautiful, it’s rugged, and it feels every bit like a premium $600 product.
In terms of the sound, it’s just a very engaging listen. You get those forward vocals that really pop in the mix, a great bass response with impressive sub-bass depth for an open-back, and a detailed, energetic treble. But honestly, the most impressive thing here is the sheer scale of the soundstage. That expansiveness is pretty special—the sound doesn’t feel stuck inside your head at all. It surrounds you in a way that feels more like a large venue than a pair of headphones.
It’s not trying to be a flat, neutral studio monitor. It’s been sculpted for musicality and engagement, and it absolutely nails that. If you want something that offers good detail retrieval, a massive sense of scale, and accurate timbre, these are very easy to recommend.
Specifications
Frequency response: 12 – 34,000 Hz (- 3 dB), 6 – 46,000 Hz (- 10 dB)
Transducer principle: dynamic
Ear coupling: Circum-aural
Sound characteristic: front-oriented loudness diffuse-field equalisation
Adaptation to individual hearing curve: Front-sided Sound Field Modulation (FSFM)
Nominal impedance: 38 Ω
Sound pressure level: 100 dB at 1 kHz, 1 VRMS
Maximum continuous input power: 500 mW (per IEC 60268-7)
Total harmonic distortion: 0.05% at 1 kHz, 100 dB
Weight without cable: 378 g
Headband clamping force: 2.5 N