I recently traded in my old iPhone 4S for a new iPhone 5S (yes, I know I’m a whole generation behind) and needed to buy all new accessories since the power and data connector changed from a 30 pin to a new-fangled Lightning connector.

I always listen to iPhone podcasts or Pandora music in my car during my commute to and from work, and I had to buy a new FM transmitter because my old one was shorted out.  My car does not have an audio input jack. Nor does it have a cassette deck.  So my only option in that car is an FM transmitter.  Those things are pretty expensive, by the way.

So I bought a fifty dollar (ouch!) FM transmitter from Best Buy which I was pretty excited about initially because my old FM transmitter was just a 5mm stereo jack and it did not power/charge my iPhone, but this new one charges the phone and pulls audio simultaneously using only the Lightning connector.  That eliminates the separate charging cable I used to use on my old phone.

Here’s the catch.  The audio coming out of the phone’s Lightning cable is hard coded in the phone to be at about 25% of full volume and there is no way to change it.  So the audio level is quite low when I use this FM transmitter and I have to turn my car stereo up all the way and sometimes that’s not even loud enough!  Very frustrating.

Also, FM transmitters are far from ideal.  They get static from all kinds of different sources.  It’s very difficult to find a frequency that doesn’t have static on it which interferes with the listening experience.

Turns out that Apple won’t let the user adjust the volume coming out the Lightning connector because manufacturers of docking products (like home stereo systems and alarm clocks) need it hard coded to a known level for various reasons.  I’m not clear on the reason they chose to make the volume so low, but some online posts mentioned that it is a safety feature to keep users from blowing their ears out.

So don’t buy Lightning connector docking products, like an FM transmitter, unless they have their own internal audio amplifier.  Most alarm clocks and stereo docking stations do, but I don’t know of any FM transmitters that do.  I had to learn this lesson the hard way.  Hopefully this blog post will save you the trouble.

Kurt