One of the great things about having a smartphone are all the different ways you can listen to audio. Playlists of music on the phone, internet radio, podcasts, playing audio from cloud storage and more.  

My first thought was how I would get the sound into and through the speakers in my car. My blue-toothless car.

My first attempt at phone-to-speakers in the car was to buy an FM transmitter. This works by matching the radio dial and the transmitter to the same station. Sound is then trans...