Sadly, my ER4B has started to malfunction. It has developed a slight buzzing/rattling sound at certain frequencies in one ear. It only happens at high volumes, and it only happens on certain tracks, but it's still annoying enough that I want to replace them.
I was the second owner, and they were originally purchased in November of 2011, so they lasted just over 5 years. I used them on a daily basis for the past year and a half, even destroyed the original chord and had to solder it twice, and finally one of the earphones has started to malfunction. It's a sad day, but I love these headphones and I'm definitely going to buy another set.
It kind of sucks because it's mostly fine. They sound absolutely perfect 98% of the time, and at low and moderate volumes you can't tell at all. It's wven when you listen at high volumes that the slight buzzing comes in, and it only happens at specific frequencies, so if you're listening to a track that doesn't have those notes, it will be totally fine. And it seems like the number of tracks it's noticeable on isn't very high, most songs are totally fine, even at high volumes, but it still happens on certain tracks and it's still broken enough that it bugs me.
I was thinking about Etymotic's replacement policy where you send in your broken set and get a rebate on a new one, but the Canadian dollar is doing badly right now that their rebate price of 179.99 works out to be $258 Canadian, and I can just buy another pair for less than that on the second hand market, even mint condition ones, so I think I'm going to do that because then I can hang on to this broken set, which actually sounds 98% fine.
Not sure what I'll do with the broken set. Maybe I'll stay on the lookout for somebody else who is selling a broken set, and I can just take a working earphone and replace the broken one. But overall, it's been a sad day!