This is just my initall very basic thoughts on the coppers,so far im injoying them , i really have not had these in my ears long enough to give eny definite conclusions just yet only got about 5hrs on the coppers so far,and only about 25hrs on the golds so i believe both have quite a bit of burn in before they settle down to the final sound.
So far im not hearing that much of a significant difference between the coppers and the gold.
Both have good detailed treble and mids ,i can't really say that i think the coppers have eny added detail that the golds are not able to retrive.and they are no more sparkly than the golds.The monsters treble is done really quite nice ,iv not heard eny sibilance from either the coppers or the golds although that said they dont have the brightest sounding treble out of my iems.
I think the bass is where you will find the biggest difference between the two
Both have that same detailed bass,very dymanic and hard hitting, but i think the coppers have a bit less upper bass which lessons the impact of the bass when compared to the golds ,this has a nock on effect of giving the mids a bit more space to breath giving the coppers a bit more of a open spacous sound compaired to the golds.
Have included some pictures below of the coppers and the golds together so you can see the difference in colour between the two,the coppers are brighter looking than the golds.
Like i said these are just my very first impressions ,so take my comments with a pinch of salt, i will post a proper review on the coppers when ive become more familiar with there sound and i will also do some direct a/b listening to the same songs to see if i can get a more defined feeling for there differences