How to amplify the phone if the sound is too small?

The mobile phone has two speakers, one on the top and the other on the bottom. The sound below is very loud. When using the hands-free key, the following sound will be activated. When the hands-free function key is not used, the voice will be emitted by the speaker above, which is only suitable for one person to put his ear to the mobile phone to answer. If the volume switch is turned to the maximum after using the hands-free key, it is still too low. You can try to answer with headphones, so there is no ambient noise, which will be better. If you are not satisfied with using headphones and hands-free, you will have to change your speakers or mobile phone. See the attached speaker: There is another way, you need to buy another Bluetooth speaker, turn on the Bluetooth switch of the mobile phone, and turn on the switch of the Bluetooth speaker, so that the mobile phone can be paired with the Bluetooth speaker, and the sound of the mobile phone will be automatically amplified. You can adjust the volume through your mobile phone or Bluetooth speaker, which is very convenient: