This is the official thread to discuss the MrSpeakers AEON Flow Open Headphones.
How do these compare to the Ether Flows since those seem to get a lot of negative reviews?
I’ve seen a number of positive descriptions of these on Reddit, and they still are on Tyll’s Wall of Fame so they must have something going for them. Maybe these can be added to the loaner program?
Over the past year I’ve had the pleasure of owning the Mrspeakers Aeon Flow Open (AFO), and while I’ve simultaneously owned and subsequently sold gear that is technically more “high end”, I find myself unable to part with the AFO. This is a hobby that often forces the enthusiast to sell off beloved equipment, just to be able to potentially step up to the next new item, but the fact I’ve been unable to do so with the AFO should be a sign that it’s doing something right. This review is the culmination of over 18 months of using the AFO and attempts to answer why I’m unable to stop reaching for it.
The AFO is a planar magnetic headphone that bucks the prevailing trend of this technology’s tendency to be implemented in cans that weigh over 400 grams cough Audeze cough. For those of us who wear headphones for over eight hours per day, this is a welcome change. The AFO weighs only 321 grams, making it one of the lighter planar cans available today - certainly at this price/performance bracket. Long listening sessions aren’t a problem at all with these and while I personally find the clamp force a bit tight with my slightly larger than average head size, a day wearing the AFO leaves me no worse for wear and the thick pads mean the pressure from the clamp force is absorbed reasonably well. Contrast this with a day of wearing the HE-500, or as I like to call it, my unwearable head-vice with bricks attached to the sides, and that’s a different story. Even in comparison to my ZMF Auteur, which is a very comfortable TOTL headphone, the AFO leaves me happier by hour six or seven due to its lower weight. Of course, it’s not a good idea to only wear one headphone all day and switching it up a bit can provide the much needed variety to make certain genres and tracks shine.
I’d have to characterize the planar sound as one that is fast, and one that represents tones as if they were plucked or pulled rather than pushed towards you. This leads to faster sounding leading edge transients and an immediacy that redounds to sonic engagement that few dynamic drivers can match. My contention has long been that this quality in a headphone is often overlooked when it comes to ultimate enjoyment. The AFO is no exception in this regard. In fact it’s one of the fastest headphones I’ve ever heard on the right equipment and describing it as “punchy” doesn’t even begin to do it justice when it’s paired with something like a Cayin IHA-6.
The resolution is up there with other headphones in its price range, but it doesn’t quite reach the capabilities of something like the Auteur or the Focal Clear. Of course, these headphones also fetch twice the price. Curiously, it was after doing these comparisons with resolution and detail that I started to think it would be a good idea to sell the AFO - after all, I had ascended to higher levels with the ZMF, Focal and Hifiman offerings. But the reality is that at this level of resolution, the small incremental improvements you might get by switching to one of those other cans stops being the salient attribute that makes one headphone better than another. Resolution at this level is no longer the critical scale for determining how enjoyable a headphone is to listen to. This fact is underscored by the AFO’s ability to draw you into the music in ways that many other high end headphones can’t quite seem to do. I have to ultimately describe it as a headphone that ensures each piece of its performant qualities - the resolution, the speed, the staging, and tonality - all work to confer sonic benefits to one another, rather than to stand alone for the listener to isolate.
Mrspeakers supplies several tuning inserts that can be swapped to change the brightness or bass levels of the headphone. My preference is to run it with either the single notch insert (medium) or the black insert (no damping), and it’s nice to have the option to switch things up to suit one’s preferences. Without question, the AFO is a bit of an unorthodox tuning, but because of the implementation of the fast planar driver, Mrspeakers is able to get away with their departure from strict neutrality here.
The bass on the AFO hits like a truck. Because of its speed and midbass emphasis, you get a tonally rich, yet tight and hard hitting punch that expertly delivers intense bass lines. Perhaps my favourite part of the AFO is that it’s able to hit hard with a slightly elevated bass response between 70-200 hz, while simultaneously refusing to bleed into the midrange in any way. I have to stress again that the bass and mid ranges are so incredibly distinct from one another that it’s remarkable, lending incredible definition to the music. This is likely another benefit to the speed of the planar driver, or perhaps the ‘Flow’ titled waveguide mechanism Mrspeakers employs. My guess is that the AFO would show a relatively fast decay on various cumulative spectral decay (CSD) graphs, but I have yet to measure this reliably.
The midrange is very clear and distinct, again due to the lack of bleed from either end of the spectrum. Perhaps somewhat subdued at 3-5khz and with a slight dip at 6khz, the AFO is able to resolve both snare drum hits and cymbal splashes well without any awkward ringing or grain that occasionally can show up in that range. This may not be to everyone’s taste, however as a drummer I find this to be a lifelike representation of the way those instruments sound. My guess as to the logic behind this tuning is that with the speed of the planar driver, an elevation in this area could result in some glare or harshness to that range, or that it could negatively impact the timbre of instruments that depend on that range. This has certainly been a problem for other headphones I’ve used in the past. Part of the tuning philosophy that goes into these headphones is that at the end of the day they need to accurately represent instruments or whatever is producing the music. Driver type, materials, and the resulting CSD contribute to sound in ways that don’t always show up in the frequency response measurements. These factors often need to be compensated for by the tuning (which does show up in frequency response measurements) to get the headphones to accurately represent things, and to my ears they do exactly that.
When I was first evaluating the AFO, I wasn’t a huge fan of the treble, but now I’ve grown to love it. There is a slight peak around the 8-10khz region, which initially sounded like there was just a touch of glare or shine across the the sibilance range. After putting the one notch tuning filter in, however, that spot remains completely innocuous. I’ve also introduced a velvety smooth dual Burr Brown DAC to my chain in the iFi iDSD Micro BL, which makes a massive difference to the treble sensitive. It doesn’t eliminate treble details, but rather represents them more smoothly and refined than my previous ESS DAC. In any case, the rest of the treble spectrum does everything right, with plenty of air and sparkle up top.
The AFO’s staging is fairly intimate, but not necessarily in a bad way. It puts the listener front and centre to the music in a way that feels appropriate. My impression here is that this presentation allows all the different pieces to come together so well. In spite of the intimacy, the instrument separation is superb, and again one of the best I’ve ever heard in that area. Finding and isolating an individual instrument or musical line is effortless, but at the same time it doesn’t get lost all on its own like it might with the HD800 for example. I can only describe this quality as having exceptional layering to the sound, such that there’s no cross bleed between tones, but at the same time the isolation doesn’t throw the separated pieces so far left and right to achieve instrument separation that you lose the point of the music.
If you’re considering the AFO, you absolutely must consider the Cayin IHA-6 in its balanced configuration (balanced is key with this amp). It’s as if these two were made for each other. My other pairings have been with the iDSD Micro BL, a Schiit stack (Modi 2/Magni 3), an iCAN Pro, an old Hifiman EF-5 tube hybrid, an MCTH and Aune X7s. They all sound fine, but none of these come close to what the IHA-6 can do with the Aeon Flow Open. The staging opens up with surprisingly more depth as well, along with an even faster and tighter impact throughout the spectrum. It’s important to keep in mind that this is a low impedance headphone (around 14 ohms) that does require amping due its inefficiency. This means that while not much will change in the frequency response if the amp pairing breaks the 1/5th output Z rule, it’s also likely not at its best with high output impedance amps. Pair it with a fast SS amp, either single ended or balanced (just make sure that if you get a balanced amp to actually run it balanced) - one that has a relatively wide and open sound, and you’ll be very happy with the result.
My preference is for music with instruments. I love Jazz and classical, and the AFO does well with those genres. But this headphone really shines with hard rock, prog rock, and metal. There’s a crunch to this genre that’s just so perfectly represented by the AFO that it’s my absolute go-to for anything with a bit more aggression and bite to it, even over my Auteur or HE-500 (or literally anything else).
Overall I think the reason I keep this headphone in my collection is because it does intimacy and engagement so well. Yeah other headphones have better resolution, or better/wider soundstage, or better neutrality. But the way the Aeon Flow Open ties everything together is very unique. It’s not a “one thing” kind of headphone that might satisfy the person looking for a particular quality in a new can. It’s instead the kind of thing that you grow to appreciate for the fact that it’s everything sound representation should be - and it makes you feel everything you should feel when listening to music.
Great review @Resolve. I found it informative and a great read. I am tempted to give these a listen.
Thanks, added a few photos because I think it looks pretty cool too!