Smart & Connected Life Connected Car Tech Connecting a Car CD Changer to a Factory Stereo Use a compatible factory design or an over-air radio signal by Jeremy Laukkonen Writer Jeremy Laukkonen is tech writer and the creator of a popular blog and video game startup. He also ghostwrites articles for numerous major trade publications. our editorial process Facebook Twitter LinkedIn Jeremy Laukkonen Updated on October 28, 2019 Joe McNally / Getty Images Connected Car Tech Android Auto Apple CarPlay Navigation Tweet Share Email There are two ways to connect a CD changer to a car's head unit or center console: through a compatible factory design or through an over-air radio signal. In almost every case, the former is preferable because it provides higher quality audio and an easier-to-use interface. But not every car is compatible with every external CD changer. If yours isn't, use an FM transmitter or RF modulator to broadcast the audio from the CD player to the car's speaker system. Any reputable car audio service can handle either type of installation. However, most people may be able to do it themselves, with a little patience. Connect a CD Changer to a Compatible Head Unit Some factory head units are designed for use with CD changers and auxiliary (AUX) audio inputs. If you're not sure if a head unit has this ability, consult the car's manual for information on audio compatibility. Or, contact a local car audio specialist to ask more technical questions, or to have them find the easiest way to connect an external media player to the head unit. Online forums and communities such as Reddit are good resources to ask questions about audio compatibility. If your head unit is designed for use with a CD changer, you may need to obtain a proprietary input cable from a manufacturer or licensed reseller. Depending on the CD changer you choose, you may also need to buy an adapter. If the CD changer is not electronically compatible with the head unit, connect it over a radio signal. Connect a CD Changer to a Head Unit Over Radio Signal FM transmitters and RF (radio frequency) modulators broadcast a signal from the CD player to the radio on the car's head unit. This works with any audio source or auxiliary media player. FM transmitters are a good choice because they're portable and don't need to be installed; you can easily move them from one car to another. FM transmitters transmit the audio signal from the input device (a CD changer, in this case) to the FM tuner in the head unit. The downside is that the CD audio is lower quality and subject to interference. For those reasons, most people prefer to use an RF modulator to connect a CD player or auxiliary audio input. RF modulators introduce an FM signal directly into the head unit using the antenna cable. This provides better sound quality but the system is more difficult to install. FM modulators also complicate the controls for the CD player. When you connect a CD player to a compatible head unit, you can switch discs, select tracks, and stop or pause playback with the head unit's built-in controls. But an FM modulator only introduces an audio signal from the antenna jack, so the control functions are lost. Most RF modulators come with wired or wireless controls that connect to the CD player. This means you won't be able to control the CD player from the head unit.