The voice of the Apple 6 handset is getting lower and lower. What happened?

The reason why the sound of the Apple 6 handset is getting lower: Maybe you turned down the volume yourself. At this point, press and hold the "+"key on the left side of the phone to increase the volume. Specific as shown in the figure below:

If it still doesn't work, it is recommended to use the "hearing aid" function, as follows:

1. Open the Apple phone, find the "Settings" button on the screen, and click.

2. After clicking in, find the "General" function and click on it, as shown in the figure.

3. Then jump to the "General" page, find and click "Accessibility", as shown in the figure.

4. On the Accessibility page, click Hearing Aids, as shown.

5. Then enter the "hearing aid" and find the "hearing aid mode". This function has not been turned on at this time, as shown in the figure.

6. Then slide the button behind "hearing aid mode" to the right to turn it into a green button, as shown in the figure.