thougt i would throw a quick note on here.
Life has kept me away...to much going on. Anyway a fellow headfier's observations on a pair of my full modded 9927's that i sent him have made me revisit just how good stock 9927's are.
First thing forget filtering...even the Rin filter kill some of the vibrancy and drive of these babies. Make sure they are absolutely sealed and break them in well and to really hear them at their best use
good equipment...not necessarily expensive just well balnced, musically neutral stuff. Cyanoacrylate damping improves them even more in that regard but getting both sides equally doped is a challenge. Larger bore noozles definetly improve the highs as do larger bore tips. The lostearbud clear double flange available on ebay feel the best of anything. My only issue is that I would like something with a longer length. I am working on gluing together stacked double flanges to accomplish this. But the lostears are soft and very compliant. Even with medium canals you can probably fit a large and get a better seal. That is a huge thing with the 9927's. I still get the best sound with hifiman large double flanges. But i have retrogressed(actually progressed back) to stock.. I prefer the feel of my tweaked foam sleeve version...but the stock one seal better. This has made enough difference along with the doping that i have completely soured on any filtering with these.
Even the rin filters...which add a very pleasing warmth and liquid but sacrifice neutrality and vibrancy and bass punch. A tight seal balances the sound so well that you really don't miss that but with filters the sound is duller and less involving despite the wonderful tonality and liquidity. That makes these even more amazing in my opinion. If your game do the rin mod cut off the noozles use 3/16" diameter pvc model tubing. Try cyanoacrylate damping as well with calibrated droppers,available at hobby stores. And no filtering. Seal them in your ears as tight as you can stand. They are amazing. Otherwise go stock get an excellent seal and be happy. Nothing under a couple hundred dollars rivals even that from my experience.