If you want to change the default audio device for calls in BIG Phone, start from the BIG Launcher home screen. Tap the three dots next to the clock and choose “Preferences”. Then choose “Phone”.
Find the audio device setting
On the next screen, find “Default audio device for calls”. The standard option, “Default”, leaves the choice to Android. Usually this means the phone earpiece is used, or a Bluetooth headset is used automatically if one is connected.
Choose speaker when needed
You can change this behavior. For example, choose “Speaker” if you want calls to start on loudspeaker by default. When you return to the home screen and call someone, the in-call screen will already show the speaker as the active audio device.
Change audio device during a call
During a call, you can still tap the audio device button on the call screen to switch to a different available device.