Lol Sony is smart.
They're using magnesium in the XBA-2, XBA-3, XBA-4 and liquid crystal in the XBA-1.
That means the people that instantly buy the XBA-4, will eventually buy the XBA-1 anyway out of curiosity, Sony has already given it a label of "Profound vocal sound".
The people that buy the XBA-1 thinking it's expensive enough already, will slowly become insatiably curious about the XBA-2, 3 and 4.
In the end Sony is making sure everyone buys at least two models to increase sales two-fold, and they sure released these all at a good time, the balanced armature IEM market is more lively than ever right now in 2011.
The XBA-3 is the one for me.
p.s. Why was my thread showing the movie about this deleted?