Martin Logan Mikros 7

According to Wikipedia, Martin Logan is an American company producing a variety of floor-standing hybrid, wall-mounted, and in-wall speakers using electrostatic loudspeaker and planar magnetic thin film loudspeaker technology, as well as conventional subwoofers.

In September 2012, they introduce their first IEM, Mikros 70, which is "inspired by the clarity and detail
of MartinLogan’s legendary high-end electrostatic loudspeakers", and should deliver "realism, richness, and purity" to listeners, according to their claim. It will certainly be revolutionary if a dynamic driver's electroacoustic performance is close to that of an electrostatic driver.

PRO: Very clean transient, Super-low distortion, and planar driver-like impedance linearity, which yields no frequency-dependent attenuation. What, no resonance?? Just feels like orthodynamic from 30 years ago.

CON: Absolutely flat. No sign of diffuse-field in its sound, similar to an unmodified UE900. A slight channel mismatch in the mid frequency range. The high frequency bandwidth is up to the specification, but with a large downward tilt.

ON SECOND THOUGHT #1: It is a good idea to insert Mikros 70 deeper into the external ear canal, since the frequency response above 10 kHz and below 19 kHz notches down as insertion depth becomes shallower. (IOW quarter-wavelength resonances shifts) The IEM's acoustic output impedance is quite for a dynamic type.

ON SECOND THOUGHT #2: Other than stock sleeves, Martin Logan also includes a pair of tri-flange sleeves in the package. As you can tell, its longer stem changes the quarter-wavelength resonance of the IEM, and cuts off the output in the high frequency range, while boosting the mid-frequency. If you can insert the IEM deep with stock sleeves, don't even bother with the tri-flanges.