*solved* Another K701 with "something loose"...

[Eldi]

Hello,

A few weeks ago I bought a pair of 701's and everything seemed well for the time. However, tonight I noticed that the left channel makes a rather annoying buzzing/vibrating sound when playing low frequencies (below 150hz) at very modest loudness, and the other channel does not have the problem at 30dB more! Seeing how the left earpiece no doubt has more wiring inside as the cable splits there, I am wondering if the problem really is a defective driver instead of a badly placed wire? Warranty aside, it certainly should not be very hard to fix that by myself...
The problem definitely is not with the source, and cleaning the pads does not change the situation.

Should I return the phones or take the risk?

Edit: Pressing the phones against my head with moderate pressure also greatly lessens the problem.

[Eldi]

After some thought I decided to crack the phones open and what did I find!
The internal wiring was touching the case at some critical spots which led to the problem. A quick reorganization of the wiring eliminated the problem and confirmed that the cause was indeed not the driver itself...

[barrybarry]

akg are really helpful on these forums