[moixa]

If not, how about openback IEMs? (other than Stax srs-002)

 

[Jazzkammer]

Open back IEMs, also known as "earbuds"

 

[JohnSantana]

How is this compare to the Balance Armature IEM or Dynamic Driver head phone ?
 
Does this type of earbuds has a specialty to be used against certain musical types ?

 

[CJG888]

AFAIK, VSonic are still working on their planar magnetic IEM. If they succeed in bringing it to market, it will be the first mass-produced IEM of its type.
 
This sort of thing is possible nowadays, as powerful portable amps are becoming more readily available and affordable. Something like a Fiio E12 or an iBasso P4 should be able to drive it well.
 
I suspect, however, that the VSonic will not be cheap...
 
There is a thread on this product on HF.