[ubs28]

Considering that BA IEM are beating Dynamic IEM, which BA headphones are out there that are good? And how good are they in comparison to planar and electrostatic? 
 
The Shure SE535 beats a top of the line Sennheiser HD800 in terms of square wave tests and %THD measurements, so the BA technology is good. Hence why I'm surprised I don't see a lot of BA headphones.

 

[dweaver]

I don't believe the technology would work for a headphone so it does not exist. Balanced armature technology was originally designed for hearing aids to make them small to fit in peoples ears.

 

[briskly]

Beating out dynamic IEMs? How so? Some of multi-BA in-ears have good amounts of high treble, but in distortion performance, they are significantly worse than other dynamic in-ears (e.g. the RE400 and MDR-EX1000). The advantages of the balanced armature are in efficient sound output and size. I guess we can also count not needing a depressurization hole as a plus as well.
 
Balanced armatures are old technology; they've been around since before the 1940s.