This is the place to discuss all things to do with the DCA Aeon Noire X. DCA were kind enough to send us some units for testing.
Check out DMS’s Aeon Noire X review:
Here are the measurements:
DCA Aeon Noire X Frequency Response (HpTF Variation)
Resolve Unit (GRAS KB50XX & B&K 5128)
DMS Unit (GRAS GRAS KB50XX & B&K 4128c)
What is this? This indicates the headphone’s behavior variation across different heads and ears, providing a better indication of how they are likely to vary across human heads as well - absent other factors like leakage effects from glasses for example.
Why is this? We have a video on the channel explaining why this type of visualization is likely necessary for headphone measurements. This should ideally evolve the more heads and ears we can test these products on, but the older paradigm of showing a single line on a graph to indicate headphone performance is insufficient.
Raw
LESS IMPORTANT DATA BELOW 
The following is not perceptually relevant unless things are awful. In the majority of cases, none of this matters.
Harmonic Distortion
94dB
104dB
110dB
Good performance for harmonic distortion, nothing will be perceptually relevant here with music, even at high volumes. Above 110dB you see trace amounts of higher order products but this really isn’t anything to worry about since that’s absurdly loud.
Driver damping (Driver Fs in the presence of an intentional leak)
Notable driver damping and a fairly high driver resonance frequency, both are to be expected for these types of headphones. In practice this won’t matter if you get any decent seal.
But if you break the seal, the bass will drop out to some degree. It likely won’t drop out as much as shown here since this is caused by an intentional leak but it’s something to consider if you wear glasses with thick arms.
Excess Group Delay (test for internal resonances)
No reason to care about time domain information here as it’s clearly minimum phase (behaving well) and therefore it’s all proportional to the FR.
Notes:
Performance is very good across the board here, with a hint of forwardness around 2.3khz. Not really anything to complain about.
Bass quality seems to be quite a bit better on these than most of the other DCA headphones I’ve evaluated, and I expect this actually could be due to the redesigned pads and it having a better in-situ response for that sense of impact. Like the pad surface area has a more uniform contact with the side of the face - at least from what I can tell.
One consideration for people looking into this headphone is that HpTF variation above 3khz may be more substantial on this one due to the nature of the AMTS (the sophisticated waveguide system in front of the driver). I expect it to perform well for people generally, but perceptually I do not hear it the way it measures, and this is similar to how I hear the other models that use this system. But for anyone for whom it does work, this is bound to be a great sounding headphone.
The one quirk around 2.3khz may be more consistent, but I wanted to note that actually this feature wasn’t unenjoyable to me. Like it added a touch of flare but I kind of liked it at times. Overall I find it to enhance certain tones from the midrange a bit more than on the Closed X for example.
Other aspects like design and comfort are all top notch, as we might expect. I do personally prefer the other headband because I find the leather on this one to dig into my head a bit, but I also have a particularly large head.
In general, I recommend this headphone because it performs quite well, but I do recommend trying it if you can, just to be sure the AMTS works for you. Is it an upgrade over the others in the series like the Aeon 2 Noire and the Closed X? If the AMTS works for you then I expect it will be. If not, then that’s a much tougher choice.
