Headphone Reviews

Sound Quality
Simply put: This is the best sounding around-ear, sealed, headphone I've heard to date. Tonal balance is spot on but for a very slight emphasis 5-10kHz. Bass is tight, well balanced and does not bleed into the mids. Transition to mids is seamless and excellent. Midrange is excellently balanced; vocals and overtones are very well proportioned giving voices just the right sense of presence and ease simultaneously. Treble is terrifically proportioned as well; cymbals and snares sound very natural. I guess my only note here is a very, very slight over-emphasis at 5kHz-10kHz. This may not, in fact, be over-emphasis as much as it is the slightly rough response in that area with proper level. Really just having to nit-pick here as the Aeon does so much so well.

Transient resolution is superb. Good presence balance give just the right sense of depth of image and really good transient resolution gives excellent separation, specificity, and stability. Though lacking the depth sometimes available in open headphones, I found the image width and depth just right for a sealed headphone.

Dynamics and micro-dynamics are quite good but not great. These don't have the eye-blinking impact of the Focal Elears, for example. I felt the Aeon sounded just slightly compressed.

I'd say the overall character of the Aeon, and it's not much of a character, was just slightly hard in the upper midrange and slightly rough, lacking in smooth liquid resolve of some top-of-the-line open acoustic offerings. That's a bit of apples and oranges comparison, however, these are sealed cans, and in that category they are remarkably even handed and responsive. Very much without any large discontinuities often found in sealed cans.

The Aeon comes with two small foam pads that may be inserted into the ear cup. Dan has long provided similar filter pads in previous models and I've always appreciated the chance to slightly change tuning to taste. Without these pads I'd say the Aeon is ever so slightly too bright for me. With the pads I find them almost exactly to taste. The pads increase bass response below about 100Hz about 1-2dB, and decrease response above 100Hz about 1dB and about 2 dB above 1kHz. Basically they provide a gentle warm tilt to most of the spectrum when inserted.

It's also worth noting that the sound of the Aeon does change somewhat with position around the ear. I found the best listening to occur when the headphone is worn slightly forward and down from a perfectly centered position. Moving the headphones back on the head, with the ear forward in the cup does add some extra brightness to the cans in the 3-8kHz area.

Isolation from outside noise is is excellent for a headphone of this type. The Aeon is a somewhat inefficient headphone; they will need full volume on smartphones to achieve a solid listening level. A portable amp or DAP with solid amp section is needed for satisfactory volume levels on the go.

A couple of technical notes.
I spent some time talking with Dan about test fixtures and product manufacturing repeatability. Most info was off the record but I can say the his methods are impressive and very well thought out. He does do driver measurements before they're mounted in the headphones and drivers are matched before installation. Once in the cans, the headphones are measured again without earpads in a specially designed fixture. He claimed significantly sub-1dB matching in this mode is the norm.

Then the headphones are measure again when the ear pads are installed. They've found that the largest variance in headphone performance comes when ear pads are in the equation. I've long suspected this is the case and it was reassuring to know his findings bear out the importance of the ear pad with headphone performance. He said they now do earpad matching as well as driver matching to insure quality left/right balance. Measurements show vary good matching for these cans. Measurements of three current production units evidence this.

Dan sent me a pre-production unit some months ago, and then an early first production run unit maybe two months ago. I found the production unit not quite as good sounding as the pre-production unit. I gave him a call as soon as I had a chance to listen and measure to ask whether that was the final tuning. He immediately said no, and that they had found a problem with the consistency of the acoustic impedance of the vent damper foam that effected a small percentage of the initial shipments, and that new foam was sourced and installed and the tuning pads were now included.

I've compiled a small .pdf booklet of all Aeon measurements made to date. The unit labeled "MrSpeakers Aeon" without serial number is one of these initial units. In the measurements you can see that there is a significant discontinuity in the bass to mid transition, and a slightly too high in level peak at 5kHz and 10kHz. Dan's estimate is that there may be 20 to 40 headphones out there with this fault.

Despite the fact that I called him only days after receiving mine, Dan was already taking measures to right the headphones out in the wild. Since it's complicated, I asked for a statement from MrSpeakers:

About two weeks into shipping ÆON we noted a couple of owner reviews that commented on a low-level of upper-bass/lower midrange output. A properly tuned ÆON has a small dip between 140 and 220Hz so we ascribed this to normal operation and added tuning foam to the product to address this. However, a few days later I listened to a “passed" unit that was definitely light in the transition region and halted production.

We discovered our measurement process was masking a tolerance issue in the aperiodic vent damping and some units were passing test but were out of spec. Affected headphones have about 2 dB extra output from 80-120Hz and about 2dB less than expected from 140-220Hz. The technical fix was to replace the foam in the aperiodic vent and change the test process. Once we confirmed the fix we sent 3 corrected headphones for test and advised you we’d made a change to production to address a consistency issue.

Our preliminary review indicated 10-20% of units shipped to pre-order customers prior to June 10, the issue does not affect units sent to resellers. We’re currently matching test data to serial number and owner and next week we’ll directly contact affected owners to arrange service. My personal apologies to anyone inconvenienced by this; this was my error when I setup the test process but I’m deeply committed to ensuring every customer has the best possible experience and that our products are consistent, reliable, and enjoyable. My thanks to those whose detailed reviews helped us track this down quickly.

I clarified with Dan: About 200 units were shipped prior to June 10 making it about 20-40 headphones potentially affected. To further clarify, MrSpeakers is able to retrospectively look at manufacturing data and identify affected units. I was in the fortunate position of observing his proactive responses and was impressed. When I told him I'd never buy something in the first production run from anybody, he answered, "But in this business the early adopters are our biggest fans; we need to honor that trust by making things right." Great stance. It's good to see a manufacturer working to make a great product even when they have to go back and fix a few. All too often that's not the case.

Summary
Under the unusual tear-drop shape of the MrSpeakers Aeon you'll find a quiet, comfortable sanctuary for sublime music listening. Build quality, comfort, and rock solid accessories complete this excellent piece of headphone kit.

With a sound straight down the middle, both audio enthusiasts and professionals will find themselves pleased as punch with this high-value audio transducer. Tonal balance and transient response are extraordinary; imaging is very good for a sealed headphone; only some roughness and slight dynamic compression belie the fact that this is a sealed headphone and isn't going to deliver the finess, smoothness, and liquidity of some open headphones.

The Aeon is going to knock its big brothers Ether C and Ether C Flow of to take the top spot on the Wall of Fame as outstanding over-ear, sealed headphone. Simply a must buy if you're in the market.