How to Use an iPhone Headphone Jack as Audio Output

By Avery Martin

The iPhone supports audio formats up to 320Kbps.
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The iPhone's headphone jack works like any other audio output line, and doubles as an audio input and output line. Connect any 3.5mm audio cable to send audio from your iPhone to a set of external speakers, an audio card or a Digital Audio Workstation, or DAW, such as Apple's GarageBand or Logic Studio application. The GarageBand iOS app enables support for mobile editing and recording with your iPhone. For high-quality audio output, consider getting external-powered audio devices to reduce interference and signal loss from your iPhone's audio output.

Step 1

Connect the 3.5mm cable to the headphone jack on your iPhone. If necessary, attach an adapter or audio splitter to allow your audio output device to connect with your iPhone jack.

Step 2

Connect the other end of the audio cable to your audio output device. This allows your iPhone to send audio to your DAW, speakers or audio card. To connect to a computer, you need an audio cable with a 3.5mm male jack on each end -- one end goes in the iPhone headphone jack, the other end goes in the computer's audio input jack.

Step 3

Plug your external audio device into a power source, if supported. If your audio output device doesn't have its own power source, connect your iPhone to the wall outlet using the USB connector cable that came with your iPhone. This helps provide additional power to the iPhone, and may reduce any static or interference that occurs when using high-end audio output devices.