i get my JVC KENWOOD HA-FX850 yesterday. i use it with Dx90 i noticed isolation is not good with default eartips. which ear tips is good for better isolation and sound response...please inform me if anyone use it.
Are you getting good bass? If so all is good, there is a port so they will never isolate to where you think they might. They are ported for better soundstage. There are some modifications you can do to help with this but I think they sound great just they way they are even with my DX90. The mods are in this thread by james444.