I have no idea why you're discussing engine oil, but to add my 2 cents( (and be hypocritical with analogies hehe), I absolutely love the UE 900s. Perhaps the sub bass impact isnt as prominent as I'd like but these are comfortably the best earphone I've owned. I say sub bass ain't that great but when i use them side by side, i only prefer the sub bass of the IE7, imho these stand up to the bass performance of the dynamic driver Miles Davis trumpet which I adored, show off how amateur the tuning of the Sony XBA4's are and you dont need an amplifier. If you had one, you'd probably get closer to a problem I will go on to explain.
They are VERY easy to drive.
Problems: And i have no nice way to say this - That F*C**NG left driver problem that makes a tearing/screeching sound.
Bloody pathetic.
If everything about these headphones apart from that wasn't so good, I'd call these the most irritating pair. A bit like XEears driver flex problem. No matter how good the IEM is, you're anticipating the next time you hear that irritating tear and it will ruin EVERYTHING about the song you're listening to. It makes me angry! I would love to fly to their HQ and choke whoever was in charge of this with the UE900! hahaha (I don't mean that literally of course)
I hate that I cannot turn the volume up too much as i hear that tear. Ironically it is when i listen to Yiruma. Piano like timbre my arse, it flipping tears at those frequencies!
(For anyone wondering what the hell im on about when i say piano like timbre, that was one of their lines in their advertisements)
This earphone is a drug. Everything about using them is amazing; the one crappy thing is the useless driver tearing/scratching issue.
I believe this is no doubt a quality control issue as with my UE700's I have the same problem in the left earphone. I have tried multiple sources (on UE700 too), both cables on the UE900, amped, un-amped. CD, mp3's, flacs, different players. I've come to the conclusion that their left drivers have some sort of manufacturing fault (or i have one hell of an exceptional circumstance)
If you listen to Jesse Cook - Ne me quitte pas,
Click here for youtube link- it is a brilliant song. These damn earphones make it sound sooo good, yet ruin everything about the song because it occurs sooo frequently.
Emma-Lee's (Emily? haha - bad joke? perhaps.) voice will give you a chill up your spine, and nearly send you into a trance....until UE's rubbish driver problem strikes again.
You will come back for a second and third listen. But as I say, this is a drug. Gives you hearing bliss, One hell of a come down too when the inevitable screech/tear happens!
Edit: Minor clarifications on what I meant.