BigBallBagCorrect, it's likely the same type of magnetostat/electret that shuoer uses in the tape/singer that they license from, I believe, earbridge.
The sonion EST drivers in higher end sets lately are ALSO actually electret drivers.
To get true Electrostatic in IEMs you have the Shure KSE 1200/1500 and Stax sr002 that I know of....
Lots of questionable marketing lately in electrostatic IEMs.....
SciHoboThe Sonion is not an electret, electret drivers do not require a transformer. It is technically a true electrostatic with a step up transformer inside the ear
DoxDrakesThat's what I thought up until about a week ago. Turns out it's smoke and mirrors. Look at the data sheet. Edit: for some reason I can't post images from my browser, so I've linked to a post about it where i was actually corrected on this same fact.
https://www.head-fi.org/threads/thieaudio-legacy-9.927889/post-15712068
SchmittABI asked the same question to myself a while back, but I think when they're the size of IEMs they require less power. Don't take my word for it, Shure has electrostat IEMs that require an energizer of their own.