I had Vlenbo's CKR9 for a week and the LTD. They are just hard to live with whether it was the odd CKR9 nozzle angle or the not agreeable over ear wearing or the no slider or the venting with wind noise. Of course today we have 70 degrees going down to 45 over the weekend here in the NE US. So huge winds blowing in towards the end of the day and the E40 did what the CKR can't do with wind that bad; have it be no real issue at all even w/o audio playing no whine or whistle. A muted rumble is all. of course the E40 are sealed so wind is kept at bay better and the isolation is better. Using UE SF/TF gray tips today which are the best for iso but sound nice and have a wide bore.
Downsides are the sealed up nature takes some off the soundstage size. Not the same as going from the Titan 1 to the 3 and 5. Still a bit bigger than the two newer DUNU but not as big as their older CKR brothers. Even though like a monitor as far as depth, width, and height being similar in amounts. The other downside is if you try to get great isolation. They are above average and better than the CKR but going higher may give driver flex with tips that seal that well.
Still burning them in but still sound like a CKR with the monitor influence in the signature. So far, they seem fairly true to source and take EQ quite well. They work well with the BGVP tuning cables and tip rolling has gone as it should as opposed to any non-expected outcomes or finicky nature like some earphones do with tips.
Sounds good with my Cowon with no sound adjustments which is tough to do. most will tell you that most Cowon's are kinda tame/cool on flat and need a bit of flavor the EQ brings. Very satisfying sans any EQ. Due in part to the warm nature countering the cool nature of the Cowon. Typical monitor warm which is good with neutral portable sources unamped but tends to go away with the sort of components one actually mixes and monitors with. I don't have my amp yet as it doesn't ship till next month
They should respond well to good clean power if they are a well done monitor earphone and shed any excess warmth low end slant.
Burn-in will show how much if any of the bass and warm will be taken off. What I would like to hear is just the bass develop a bit more and layer out and the treble has a tiny bit of sizzle with cymbals. Though if using the BGVP A cable any issue goes away and they sound very balanced and pristine. The cables are good to have in your kit anyway but they could be a must buy to go along with the E40. Then you can tune to whatever sources you have quite well in the case of the E40.
Of course, no Cowon, no BGVP cables, no Tingo flocked tips or Whirlwinds the last time I had one of the CKR's on hand so pretty much a whole new ballgame to me to try again with the CKR. Not sure I would have gone for essentially another CKR if not for my changes though I am very happy with how nice an improvement they are to live with everyday. I am really thinking they are gonna be keepers.