I am owner of a 685i headphones Sennheiser PX Adidas sports "made for ipod iphone ipad" according to package directions. So at the CTIA standard. I used this headset with a Motorola Razr and an MP3 player and stereo headset function worked great. As against the "remote control" was not functional: no call pickup, volume or track jump with the 3 buttons on it. With the adapter, instead of getting better, everything is worse: the sound becomes almost inaudible, and Mono. Surprise by pressing the center button on the remote control: the sound returns to normal volume and stereo ... as long as it is pressed!
I bought from an Xperia Z3 compact headphones without an adapter worked fine, but bonuses, acting on the center button call pickup and mic work. I was hoping that the adapter brings me more volume setting (or the track jump?). Nay: the adapter brings the same problems with the 2 other devices. I wonder if the Z3 is not the CTIA standard. In any case the adapter is to be avoided in this case. I could return without problems to Amazon.
