Grell OAE-2 headphones
I know what at least a few people reading this are thinking; something along the lines of ‘oh look, another headphone from a company I’ve never heard of.’ While it’s not unreasonable to be unfamiliar with Grell Audio, the activities of its founder might be better known. Axel Grell, founder of Grell Audio was the lead designer at Sennheiser between 1991 and 2019 and had either complete or significant input into most of the models designed in that time. As this includes a great many over ear designs, there is more than a suggestion that Grell Audio might have a handle on the business of designing headphones.
This is not to say that the company has got straight into the business of full size models like the OAE-2 you see here. Their first product was actually a true wireless earbud called the TWS-1 which, while very good indeed, had almost nothing in common with the OAE-2. Then again, in one specific regard, the OAE-2 has very little in common with any other headphone on the market.
The point of difference concerns how the drivers are mounted in the OAE-2 which is the result of a research program that has been conducted with the IKT (Institute for Communication Technology) at Leibniz University Hannover; an organisation involved with a fair few audio projects. Their input has resulted in Front-sided Sound Field Modulation (FSFM) technology.
This seeks to more accurately reproduce the listening experience of a pair of speakers that are placed in front of the listener in a conventional stereo arrangement. That is speakers that are in front of the listener, angled to each side, creating the conventional ‘listening triangle that in turn generates a convincing stereo image. This is not how drivers in a normal headphone are placed and means that even with the application of a shovel full of DSP, the listening experience will be different.
The Grell OAE-2 seeks to avoid this by placing its drivers at the front of the enclosure, angled back in a such a way that they more accurately replicate a pair of speakers. Angled drivers are not a new idea; Bowers & Wilkins has been doing it for some years, but the Grell is the most extreme example I’ve seen so far. The driver position is only part of the process too. The curved open area of the OAE-2’s baffle is twice as large as that of comparable headphones. This design allows the sound to spread naturally without being reflected by large, acoustically closed areas; more accurately replicating in-room listening.
The driver itself is not particularly radical. It’s a 40mm unit made of bio cellulose, also known in less dramatic terms as ‘paper.’ These drivers give the OAE-2 some reasonable if not groundbreaking measurements. Grell’s own website quotes 12Hz – 34,000 kHz at +/-3 dB which is perfectly respectable but not something outside the scope of what similarly priced rivals can manage. As an open back design, it’s not completely isolated from the outside world but it’s better than some designs in this regard and noise leakage from what you are listening to isn’t too intrusive either.
What you can’t see (and that isn’t necessarily reflected in those figures) is that the entire construction of the headphone has been performed with a view to improving the bass response via resonance control. The Grell OAE-2 consists of a metal frame that holds the enclosures firmly in place. The enclosures themselves are the made out of of high-quality materials including plastics, zinc, and stainless steel combined in such a way as to provide self damping. The manner in which the Grell does this is something that the company is understandably tight lipped about but looking at the combination of relatively heavy frame and the lightweight mesh sections, it would appear that some excess resonance is simply bled off but low frequency energy is coupled and harnessed effectively. Certainly, that metal frame feels extremely inert and sturdier than many of its rivals.
Aesthetically, the Grell OAE-2 is unmistakably German in design. I’d hesitate to describe them as pretty but the result is clean and modern without being so of the moment that it’s likely to date like milk left in the sun. My positivity towards them is helped by the standard of build and finish being good and the headphones themselves being comfortable and practical. The Grell uses cloth pads for the band and enclosures and, while this can be a bit much in very hot weather, I’ve found them comfortable to wear. One nice touch is that the pair of detachable 1.8m cables; balanced and unbalanced, can be connected to either enclosure depending what side the source is relative to you. Grell also supplies a decent protective case inclusive in the asking price.
Sound quality
My positivity towards the Grell has not been limited to its sturdy build and decent accessories though. In one specific regard, this £500 headphone can do things that no other headphone I’ve tested can replicate. I use headphones as a substitute for listening to a pair of speakers. The OAE-2 does a better job of recreating that experience than any other headphone I’ve ever tested. The opening Epic on Calexco’s Algiers rises from silence and it rises ‘in front’ of you in a way that feels entirely counterintuitive in terms of the sensation on either side of your head. It’s important to stress that some headphone users are not looking to replicate this perception and for them, the Grell is going to be a different listening experience but I suspect Grell understands this. By the by, it also means that putting the Grells on backwards sounds properly weird.
This isn’t the OAE-2’s only virtue either. The effort that Grell has put into the resonance control and bass extension has been rewarded with bass that, beyond the on paper numbers, is potent to the point where you can at points feel it on the side of your head. The huge low sounds that underpin the first ‘Act’ of Dead Can Dance’s Dionysus have a seismic quality to them that greatly helps the immersion and realism of the track.
Tonally, the Grell OAE-2 is more than respectable too. Katherine Priddy’s superb vocal turn in Matches is a properly spine tingling; the balance she walks between beguiling and genuinely unsettling is something that the Grell delivers exceptionally well. It can replicate strings and pianos with an assurance that ensures you suspend disbelief and simply enjoy what’s happening. At my most critical, I would say that some fine detail that can be heard on a device like the similarly priced Focal Hadenys can be harder to discern here but this is the sort of thing you would need to be listening side by side with another device to determine; on its own, the Grell never feels like it is losing or masking information.
There’s something else that’s quite interesting too. I had some concerns that the Grell’s unique configuration would result in a device that didn’t respond terribly well to external software and tweaking. Interestingly, this hasn’t proved to be the case. Adding crossfeed; something I am a huge fan of with headphone listening, is every bit as effective here as it is with more conventional designs.
Listening to Peter Gabriel’s Live at WOMAD 1982 through the OAE-2s the crossfeed heightens the sense of realism by bleeding some of the left and right channel into the other (more closely replicating what your ears hear when listening to speakers). This is partnered with a responsiveness to external DSP adjustment that augurs well for enthusiasts of this approach. Against this generally amenable disposition, it’s worth pointing out that the OAE-2 isn’t the most sensitive device going but it hasn’t been beyond the capabilities of any of the test electronics here.
Verdict
What results is a very talented and capable headphone; exactly the sort of thing you might expect from someone who designed as many notable models for Sennheiser as they did. What elevates the Grell from very good to notable is that driver placement and the effect it has on the overall performance. If your headphone usage is to sit wearing cans in front of your system when you can’t listen to speakers, you need to listen to the Grell OAE-2 because the experience it generates while you do so is so uncannily similar to the real thing. You might not have heard of Grell Audio up to this point but I suspect that won’t be the case in the years to come.
Pros
Exceptionally speaker-like soundstage and imaging
Powerful, immersive bass with excellent resonance control
Natural, convincing tonal balance with strong vocal reproduction
Solid build quality with comfortable design and useful accessories
Responds well to DSP and crossfeed adjustments
Cons
Styling is functional rather than luxurious
Not the last word in fine detail retrieval versus some rivals
Open-back design offers limited isolation
Slightly power-hungry compared with some headphones
Unusual presentation may not suit traditional headphone listeners