Let’s say you’re listening to music using your Bluetooth speaker, and you get a call. When you answer that call, the audio will probably default to your iPhone. But what if you want the call to always default to your Bluetooth headphones, speaker, or earbuds? You can select which Bluetooth device your call audio defaults to in the Call Audio Routing settings in the iPhone Settings app. We've already covered Bluetooth pairing to your iPhone, and how to change which Bluetooth connection you're using to play audio from your iPhone or iPad. Now, here’s how to set your speaker, headphones, or earbuds as the default audio on your iPhone.