This link to a new earphone is the third instance I'm aware of a Dirac DSP being applied (via an Apple 'app') to a commercial headphone/earphone product. I've tested the Apple earbuds and Earpods and the t-Jays Four IEM, and this XTZ is a new IEM utilizing the Dirac DSP. I followed the articles relating to sound correction and impulse response in the Journal of the AES many years ago, and apparently now that digital music players like the Apple i-devices have the computing power to apply a true DSP code to digital music tracks, this is what we get - i.e. fantastic sound from inexpensive transducers. I'm still waiting for a Dirac-like DSP made for a high quality full size headphone.
http://www.xtzsound.eu/en/products/earphone/earphone-12#.UMiAL7S6_zI
http://www.xtzsound.eu/en/products/earphone/earphone-12#.UMiAL7S6_zI