Hi I am pretty new to this forum and good headphones in general, and have used it to learn which noise cancelling headphones to purchase. After lots of reading through peoples opinions I ended up getting the Sennheiser PXC 450's and am very happy with them.
The headphones come with a detachable headphone cable, which I tried pulling out. When I removed it I noticed it has a 4 conductor 2.5mm pin connector where as the opposite end you plug into your mp3 player has only the standard 3 conductor 3.5mm pin connector.
I looked through the headphone specifications and could not find anything. I then tried looking this type of connector up as I know my mobile phone hands free has one similar, which of cause is because of the microphone for talking on the phone. I looked up wikipedia, as you do, and have found out it could be a TRRS connector.
I have used my multimeter to establish the difference between both the headphone end and the mp3 end. As shown in the attached pic, pin conductor 3 is open (not connected to any of the pin conductors on the MP3 end).
I was wondering, what this extra conductor could be? I have noticed this thread which mentions the TRRS connector and am unsure if this is somehow related to that. Other then this I haven't found a thread specifically talking about these headphones with the TRRS connector. (Please correct me if I am wrong)
http://www.head-fi.org/forum/thread/497427/balanced-trrs-connector-on-future-hifiman-iems
My other theory (or dream) is that it could use the noise cancelling microphones build into the head phones to actually be used to send signal down this 3rd conductor to my mobile phone (If I get a 3.5mm TRRS connector) if I was using it as my MP3 player, meaning I could actually talk to someone on the mobile phone while wearing the headphones?
I understand that I could probably make a cable up with a 3.5mm TRRS connector and a 2.5mm TRRS connector for the headphones end and try it in my mobile, but I also dont want to wreck anything (mobile or the headphones).
Does anyone have any suggestions / info on this connector and why or what it would be doing with my headphones?
Many thanks
Ben
