Hey guys! Im thinking about buying a pair of bluetooth Sennheiser PX210BT headphones! The problem is that i don't understand whether or not i need a bluetooth transmitter to these headphones? The iPhone already has bluetooth? isn't that enough? If i need the transmitter, then does the one and same transmitter work with all bluetooth headphones and do all bluetooth headphone need a transmitter? My main purpose for use of the headphones are listening to music. Help please!