So I've wanted to do this for a long while but never had the time. I'm going to be comparing the CCA C10 OOTB with my older set which has at the very least 100 hours of pink noise/music burn in. This won't do anything to solve that age old audiophile debate but I've read on many reviews that 100+ hours did a lot to the OOTB sound signature, most saying a smoother sound.
I really wasn't expecting any change as I've never really bought in to burn-in apart from brain burn in... but with the C10 anyway... there's a MASSIVE change. In a nutshell the first thing i noticed is volume. Burnie I was listening at 60% volume on my DAC. With OOTB I had to go to 75-80% for same level.
BASS
OOTB - very weak, close to anaemic. Very dry and thin... tho you kinda hear some similar depth in sub notes albeit very strained.
Burnie - stronger, much more pronounced and forward and well fuller
MIDS -
OOTB - thinner but at this point as the bass is weaker they are actually slightly clearer believe it or not. Detail is easier to spot for this same reason, albeit still a more brittle softer mids.
Burnie - thicker and that bass is making them much smoother and they've more weight behind notes, especially vocals. I'm actually noticing a good bit of over emphasis from teh bass which actually is bleeding more in to the lower mids than I'd noticed before. Still the fuller sound is more satisfying and natural. Mids are definitely pushed slightly more forward now.
TREBLE -
OOTB - Again pretty thin sounding but without that big bass change still to happen they sound cleaner and clearer, more airy. Cymbals sounding especially realistic at this stage. I'm not noticing any brightness at this stage
Burnie - Follows suit from mids, bit fuller, everything has more weight behind it giving instruments a bit more of an organic sound.. Some overall bass bleed is hiding detail a little (and i mean a little).
Soundstage - very similar in width depth. The oldie sounding more airy cos of that lack of bass, burnie having more scale due to that better volume (helped by the bass)
Conclusion
Well in the case of the CCA C10 there's obvious improvements over time. As i said, a more fuller, smoother sound. Everything just sounds more natural, but there is some bass bleed that does make them less airy... but that's always going to be the case with mids and treble given more room to dominate and breath. Bass makes the biggest change, much more elevated.
Would the OOTB sound put some people off... a clear yes. You may be led to believe that there's something wrong with the earphone due to the tinny, rattly bass which has little to no strength or definition.
Hopefully some of you might find this little experiment fun to read.