it's using the sony hybrids types but with no foams inside.
the E12 has a more energetic sound, while the X12 is natural and relaxing. direct comparison is a bit hard between them. i do personally prefer to have X12 sound in an IEM form, but this E12 is also good.
to me personally, the E12 has the edge compared to the 65t in sound, battery life, and comfort..not to mention price. so i think it's better to have X12/E12 combo than X12/65t combo
I am really curious about this, but does the x12 fit in the e12 case and vice versa?