I have been arguing with some friends about the way my Urbanears Zinken could be used as a pair of microphones. After I have inserted my amplifier aux-in cable into one of the headphone holes (another input) and after I have powered the amp, I was able to hear on the speakers what I was saying through the two earpads. My voice had a very low-frequencies tone, and even with the graphic equalizer of the amp I couldn't adjust it remarkably. My friends think it's the noise cancelling microphone, but I don't agree with them. Zero, Urbanears doesn't mention any noise-cancelling technology apart from the thick soft pads. First, shouldn't a noise-cancelling mic be placed externally? I suppose it wouldn't be useful if placed inside, because most of the sound inside the earpads is made by the song (heavily bass boosted by my headphone drivers). Second, if it really is a noise cancelling mic, why does it carry the received sound through the jack cable? Isn't it necessary to carry the sound to the driver to obtain a destructive interference? Why would my iPhone need to know what the external sound sounds like? Third, if I talk while I'm listening with an ear to the other earpad, I can hear nothing. I can only hear my voice because it goes through the amp and reaches the speakers (and because the amp volume is high). Instead, I think it's about the headphone drivers that work as a low quality mic diaphragms and convert the air vibrations into electromagnetic signals, that continue the circuit (in this case, the jack aux-in cable). These are my toughts about the situations, let me know your opionions. I haven't got other headphones with detachable cable, so I'm unable to do further tests. Also, I've inserted my earbuds into the mic-in input on my pc, and recorded my voice with Audacity. They recorded very quietly but hey, I think this confirm my hypothesis.