OK did a quick search and unless the specs are all just hype here are the differences:
SE115
Speaker Type: Dynamic Micro Speaker II
Sensitivity (1mW): 105 dB SPL/mW
Impedance (1kHz): 16ohm
Frequency Range: 22Hz - 17.5kHz
SE215
Speaker Type: ??
Sensitivity (1kHz): 116 db SPL/mW
Impedance (1kHz): 27ohm
Frequency Range: 22Hz - 18.5kHz
So I don't know what they are calling the micro speaker but the sensitivity, impedance and frequency ranges have all changed so I do think this will be a different driver.
And yes I was thinking about the fact I have taken two for the team so speak as I could not find any good reviews of the Denon AHC-560R and now this one LOL. Having said that I do enjoy the 560R a lot so hopefully these will be a winner as well.
Also according to Softpedia, "SE215 Sound Isolating Earphone, featuring a newly developed Dynamic MicroDriver".
Edited by dweaver - 3/6/11 at 2:56pm