[TNTDOG]

Apologies if this has already been answered in another thread.  Search didn't find anything specific.  Please let me know what is / isn't possible with IEBs in FPS.  Thanks in advance!

 

[cskippy]

I'm assuming you mean IEMs as in In Ear Monitors?  If so, in my experience depending on the IEM they can provide excellent imaging capabilities as in the correct position from left to right.  Most IEMs have a harder time creating proper depth which is really important for video games especially FPS.  I've tried Carbo Tenore which are exceptional for left/right imaging but have zero 3D depth for games.  
 
An exception would be 1964 Ears Adel U8.  I'm not sure if it's the Adel module or what but these create an excellent 3D space.  While not quite a perfect circle, it would be equivalent to an oval.  Still excellent plus the isolation helps to hear small audio cues such as enemy footsteps.  
 
If your looking to get an edge in FPS from headphones and positional audio get some over ear headphones like Sennheiser HD598 or my preference HD600/HD650.  These can't be beaten for soundstage depth/imaging.  Although the absolute best headphone I've tried for positional audio is the Sony MDR MA900.

 

[Eryk96]

if you are looking for positional accuracy try the AD700X, Sennheiser HD598's or the AKG 701's depending on your price range