There is no way to make the handset and speaker of a mobile phone sound at the same time.

1. The two cannot sound at the same time, and there is currently no software that can achieve this function.

2. After the headphones are plugged into the phone, the phone will intelligently recognize and jump to the headphone mode, and all audio output will be produced by the headphones.

3. After the headset is unplugged, it will automatically jump to the external amplifier mode, and all audio output will be produced by the phone speaker.

4. Some mobile phones can intelligently switch between the earpiece and speaker, just replace them.