The voice of Oppo mobile phone suddenly becomes smaller and hoarse.

If the sound is low when the phone is muted or turned off (speaker), I suggest you try the following methods:

1, turn up the volume to see if it is normal;

2. Check whether the hands-free volume of mobile phone calls is normal, and eliminate abnormal resources such as video and music;

3. Whether the sound hole of the speaker is blocked by dust or has foreign objects, you can try to clean the sound hole with a dry soft brush;

4. Restart the phone and observe whether it is restored;

5, backup data (contacts, text messages, etc. ), restore the factory settings;

If the problem persists, it may be a hardware failure. Please bring the purchase invoice, warranty card and machine to the OPPO customer service center for testing, and professional engineers will solve it for you.