I measured the Edition Xes using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I tried the headphone at several different positions on the ear/cheek simulator, to find the one with the most bass and the most typical average response. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.
This chart shows the Edition Xes’ frequency response, which is flat up to 1.5kHz. The strong peak at 3kHz is found with most headphones, and is thought to make them sound more like conventional speakers in a room, but this peak is stronger than we usually see. The bass is a little rolled-off compared with some other open-back planar-magnetic headphones.
Adding 70 ohms output impedance to the V-Can’s 5-ohm output impedance to simulate the effects of using a typical low-quality headphone amp boosts the Edition Xes’ bass below 80Hz by about 1dB -- a subtle difference.
This chart compares the Edition Xes with three other open-back planar-magnetic models: HiFiMan HE1000, Audeze LCD-3, and Oppo Digital PM-1. Compared with the HE1000s, the Edition Xes have less bass but also less treble above 3kHz, so the two might have a similar perceived tonal balance. But there’s no denying that the Edition Xes’ 3kHz peak is stronger than average.
Like the HE1000s’, the Edition Xes’ waterfall plot doesn’t look clean at first glance, but all those resonances in the high frequencies are extremely narrow and well spread out. There’s almost no resonance in the bass, which is unusual for headphones, even open-back models. I speculate that the only resonance seen here that might be readily audible is the one centered at 1kHz.
The total harmonic distortion (THD) of the Edition Xes is insignificant even at levels far too loud to listen to safely.
In this chart, the external noise level is 75dB SPL; the numbers below that indicate the attenuation of outside sounds. Like all open-back headphones, including the HiFiMan HE560s and Audeze LCD-Xes shown here, the Edition Xes offer essentially no isolation from outside sounds. I included the isolation measurement of the Oppo PM-3s to illustrate the difference between open- and closed-back models in this regard.
The impedance magnitude of the Edition Xes is almost perfectly flat at 21 ohms; the impedance phase is about as flat as it gets.
The sensitivity of the Edition Xes, measured between 300Hz and 3kHz with a 1mW signal calculated for the rated 25 ohms impedance, is 96.5dB. That’s below average for headphones in general, and much less than the specified 103dB (HiFiMan doesn’t specify the conditions for that measurement), but it should be adequate to get a fairly comfortable listening volume from a smartphone.
. . . Brent Butterworth