OPPOR9m will be quiet every time the call lasts more than 20 minutes. What happened?

Don't touch the volume down button during the call. If you don't touch it, I suggest you take it to the customer service center and let the staff handle it for you.

Solutions for low voice of mobile phones;

1. When speaking, the receiver mouth is not well aligned with the ear position. Try again after adjustment.

2. During the call, use the volume up button to turn up the sound.

3, check whether the film, holster, etc. are in good condition. Is the receiver blocked? If so, please take it off and observe.

4. Whether the time and place of replacement and the exclusion of contacts are due to network problems.

If the above methods fail to solve your problem, please back up your mobile phone data (mobile phone number, SMS, photos, etc. ) and bring the purchase invoice, warranty card and mobile phone to the nearest OPPO customer service center for testing and processing.