MrSpeakers Aeon Flow Open Planar Magnetic Headphones Measurements

Click on graphs image to download .pdf for closer inspection.

I need to say right off the bat that I had a hell of a time with noise on my THD+noise plots during this measurement section. I retried the measurement numerous times and was able to make some improvements. The best take and probably most indicative plot was on the no filter measurements. I'm only going to show the image of the "one notch filter" plots image above as they're so similar. You can find all the plots here: no filter; black foam filter; one notch filter; two notch filter.

Here's an overlay of averaged raw responses for all four configurations.


In my measurements the biggest changes were in the 2-10kHz region and at the 19kHz peak.

Back to my analysis of the "one notch filter" measurements shown at the top of the page:

Raw frequency response plots show a well extended and essentially flat bass below 60Hz. the discontinuity between 60-100Hz is likely "pad bounce," which I find in audible in headphones as a rule.

From 100Hz to 1.2kHz response is a linear but gently falling about 5dB overall. I think this part of the response is responsible for the very slightly muffled or veiled character heard in listening.

Response above 1.2kHz rises to a peak 10dB higher peak at 4kHz. Usually I like to see this peak at 3-3.5kHz, but had no issues with the slightly higher frequency peak. Though the target response would have the peak 13-15dB higher than baseline, I do find 10dB peaks perfectly acceptable...and maybe even preferable given my tendencies towards a warmer sounding headphone.

The drop from 4kHz to 7kHz again is a warmer than neutral respons, but not unusual. The spike at 9kHz is somewhat variable with the different filters and is likely responsible for the slightly sparkly response that can be nicely modulated with the various filters. The peak is also common to most of my measurements and is likely an ear canal resonance that is not heard as a peak in listening. I sure didn't.

30Hz squarewave does exhibit an odd swayback shape and is likely due to the sloped midrange response and pad bounce. This may also be indicative of the slight "bloom" I heard in listening. Note the waveform remains above zero until the end indicating excellent bass extension.

300Hz squarewave overshoot is substantially lower than I would like to see, and rather surprising to me as I heard these cans as having a well balanced and clear treble. The gentle shoulder subsequent to the peak is indicative of a moderately warm headphone. Though a tad noisy, there is no significant ringing or other features, and is quite clean for a planar magnetic.

Impulse response shows a very clean initial transient with little subsequent ringing compared to most planar magnetic headphones.

THD+noise (ignoring the noise artifacts) is very low. I heard zero sense of hardness in these headphones; everything was very easy to listen to.

Impedance interestingly shows a little rise in the low and high frequencies, which is quite unusual in a planar magnetic headphone. Nominal impedance is 11 Ohms.

Isolation plot does show about -10dB of isolation in the higher frequencies. Quite unusual for an open headphone.

Needing around 140mVrms (averaged over the four plots) this is a fairly easy to drive planar magnetic and will achieve resonably loud levels from a portable device.

The measurements are good...but not nearly as good as the Aeon Flow Open sounds. Funny how that happens. Live and learn.

MrSpeakers Headphone Products
3366 Kurtz Street