This is what Brian explained on wakeworld:
so maybe iphone has the BT4.0 but not the apt-x.Quote:
<the exbt4> ...has built in aptX codecs for higher streaming rates up to 384 kbit/s. that codec is top dog when it comes to sound quality compression. I should also say in fairness, that awesome aptX connection is not available for iPhone users as of this date. There are rumors that the next iPhone update will include the aptX codec.