Disclaimer: By no surprise, this is James' pair. Truly a great friend.
In April 2012, Sennheiser introduce their innovative In-ear monitor, IE800, to the public. Designed by Axel Grell, who is the mastermind behind HD800's brilliant ring radiator driver, IE800 is equipped with several key features:
1. Extra Wide Band (XWB) driver with the rated frequency response range of 5 to 46.5 kHz
2. Precisely controlled air flow minimizing THD to less than 0.06 %
3. The dampened-two-channel-absorber (D2CA) reducing insertion-depth induced peaks4. Diffuse-field equalized sound
5. Ceramic housing & detachable kevlar-reinforced cable
Unlike some manufacturers that exaggerate their technologies with commercial bluff, Sennheiser have always been quite truthful to their claims: Such as this and this. Once all these claims from #1 to #4 on IE800 turn out to be legitimate, not only IE800 will become the king of the high-end IEMs, but their technological superiority will also once again be fortified.
CON: There is a slight interchannel variance in the low frequency range, possibly due to the manufacturing error on the vent hole. Surprisingly, IE800 is not diffuse-field equalized, but rather is simply flat without any of HRTF in consideration, just like that of Martin Logan or Ultimate Ears. While such tonality is not of an issue at all, the fact that the manufacturer's specification indicates "diffuse-field equalized" should leave an impression of a false advertisement. Moreover, the XWB driver's high frequency bandwidth does not even reach 19 kHz, which means that the manufacturer specification is extremely misleading.
ON SECOND THOUGHT #6: In conclusion, while #2 and #3 of their claims turn out to be legitimate, #1 and #4 are somewhat commercially oriented. Since even a microtransducer with the widest frequency range measured in the free-air may behave oddly in the ear canal, their mistake is somewhat understandable. (And that is why Sead Smailagic of Sony Mobile designed MH1's driver with the ear canal acoustics in consideration) In regards to #4, the diffuse-field claim.. I don't have a slightest clue what the designer, Axel Grell, was possibly thinking..