There’s no cheaper or easier way to listen to your iPod or MP3 player through your car’s sound system than with an FM transmitter. These devices connect to the player and broadcast the tunes on a low-power signal which can be picked up by the car tuner as if it was a conventional radio station. But which works best? We tried 12 of the top sellers to find out.

The test
OUR winner had to fit the Apple iPod dock as well as the headphone socket and line-out used on other players. We used iPod 5G 30GB Video and Sony Walkman NW-HD3 MP3 players via the standard radio/CD player in a BMW 320d.