[nehcrow]

How is the isolation of the RE0 compared to HD 25?
I really liked the RE0's isolation as it wasn't overly noise-cancelling, it was juuuuuuuust right. 
I heard the RE0's isolation wasn't that good for an IEM but IEM's pretty much have the greatest isolation out of any headphone technologies, so I'm thinking RE0's isolation would be about equal to the HD25??

 

[nehcrow]

BUMP

 

[nehcrow]

bump

 

[psygeist]

Never listened to HD 25. But one can get much better isolation with smaller IEMs which allow for the deep seating of tri-flanges.
 
However I could only use a bi-flange (MEElec thick bi-flange) in case of RE 0. Still it was much better than single ones.
 
What matters is finding the perfect size of tips to fit your ear canal. I never got a perfect seal from default tips provided, except for the large bi-flange but with still room for improvement.

 

[kmhaynes]

Well, the RE0 and HD25 are different designs, obviously, so their isolations rates will differ.  I didn't have these 2 phones at the same time, but the HD25 has better isolation (when positioned correctly on the ears) because it is a closed headphone with no porting.  The RE0, like most dynamic IEMs, has a small port to allow air movement and that reduces the isolation some.
 
If you want the most isolating IEMs available, you need to look at the Etymotic line.  All are closed phones (with armature drivers, not dynamic) with small nozzles allowing for very deep ear canal insertion, the best being their 3-flange tips.