Disclaimer: Yet again, I should thank James for providing me with more than I could have ever hoped for.
Piano Forte VIII, also known as FI-DC6102SB, is one of Final Audio Design's flagship electrodynamic models. Originally designed to be completely sleeveless like any intra-concha earbuds, Piano Forte VIII is truly an unique IEM. As sleeves couple the acoustic transmission between the IEM and the ear canal together, with such sleeveless design, the radiation impedance caused by leak interferes the bass response greatly. However, according to the manufacturer, the IEM comes with their all-new cutting edge technologies that can negate all of the intereference.
However, there is absolutely nothing new about their claims, as such tweaking techniques can be seen on any IEMs from Sony MDR-EX1000 to the budget-priced Monoprice 9927. As their controversial Balanced-Air-Motion technology turned out to be a commercial gimmick previously, it is not very hard to imagine that they can also be complete bogus as well.
PRO: Both channels are extremely well-matched for an intra-concha earbud.
CON: Not only the IEM does not have any sub-bass, the frequency range from the mid and above is awfully disconnected due to peaks and deep-nulls. The tonality itself is like that of a speaker attached on an iPhone. As its sound quality turns out to be inferior even to that of Apple Earpods, it is quite evident Final Audio Design's tweaking techniques are nothing but hoax.
ON SECOND THOUGHT #4: Although there is no hope for this outlaw that defies the law of electroacoutics, it might still be possible to retain some linearity with careful modification even under a normal amount of leak. Thus, here is my recommendation for Piano Forte VIII users:
While the sleeveless design is a brilliant idea for its independence from tight acoustic coupling, the execution done by Final Audio Design turns out to be extremely poor. I think we will be able to listen to IEMs without sleeves someday, but now doesn't seem to be the time yet.