This is just a small theory on my part, but I can't help but wonder about this after having an interesting experience with two similar in-ear sets.
I currently have an Sony EX300 (those vertical in-ears) with 13.5mm drivers sticking outwards lol.
I recently got given some noise-cancelling earphones which are the Sony NC33s. (that's digital noise cancelling)
Given how similar they look I thought hmmm chances are they probably use the same drivers and the performance would be pretty similar. Doing a bit of research here most people seem to agree that the cost of NC's in majority comes from the noise-cancelling technology itself and where as the IEM itself would be ok at best and doesn't justify a high price (I live in Australia btw).
I decided to take them for a spin and using my Walkman Z to play a range of FLAC, MP3, and m4a files I used the EX300 and the NC33 to play through my favorite songs.
While I have used the EX300 for a while, I was able to find some differences between it and the NC33.
The NC33 seems to be slightly better than the EX300 in terms of bass texture (NC's seem to be a bit more Solid), Midrange (NC's seems to do a better job at presenting them), resolution (NC's sound more vivid) and the overall sound (NC's are bit more I guess Natural is the word?)
What do you guys think?
Its a slight difference of course, but has anyone else ever thought that NC in-ears maybe slightly better tuned than the original unit from which they were derived from?