Similar problem.
I've got K172s here. Been using them for little more than 3 months now, around 6 hours a day and the left driver sounds like there is something loose inside (so to say), very obvious/annoying when listening to low frequencies, otherwise still audible until mid-high frequencies. Tested on x-fi prelude with equaliser/bass boost turned off, 100% volume (it's still there on 50%, I usually listen to around 40% where it's also quite annoying but then I've turned on the bass boost/equaliser so it's not that different). Same thing happens on an iPod touch 2g, an XQ-100, some integrated laptop sound card, an iMac... Guess the source is not to blame here
To an extend it actually sounds like distortion and I'm wondering whether I've damaged the cable somehow. I'll be going to the vendor tomorrow, will edit if there's anything to add. Good luck
Just to add what I'm listening to - mostly everything, lately vibrasphere.
EDIT:
My bad that I didn't see those earlier...
This and, more importantly,
this Very interesting.
Your description of the noise sounding like "there is something loose inside" perfectly describes the problem I have with the K-701.
AKG must be aware of this problem - there are numerous posts on here about exactly the same thing - yet, like so many companies they still sell their defective goods and leave it up to the purchaser to sort out.
Do these people not have a quality control department? Or perhaps they are not familiar with the saying "Once bitten twice shy".
My K-701s will be going back.
