Adjust audio and visual settings on iPhone
You can adjust audio and visual settings such as mono audio, audio balance, noise cancellation, and LED Flash for Alerts.
Adjust the volume balance and mono audio
Go to Settings
> Accessibility > Audio/Visual.Adjust any of the following:
Mono Audio: Combine the left and right channels into a mono signal played on both channels.
Balance: Drag the Left Right Stereo Balance slider.
Control noise cancellation on iPhone
Noise cancellation reduces ambient background noise on phone calls when you’re holding the receiver to your ear.
Go to Settings
> Accessibility > Audio/Visual.Turn Phone Noise Cancellation on or off.
Flash the LED for alerts
If you can’t hear the sounds that announce incoming calls and other alerts, iPhone can flash its LED (next to the camera lens on the back of iPhone). The LED flashes only if iPhone is locked.
Tip: LED Flash for Alerts is a useful feature for anyone who might miss the tones associated with calls and other alerts in a noisy environment.
Go to Settings
> Accessibility > Audio/Visual, then turn on LED Flash for Alerts.To prevent LED flashes when iPhone is in silent mode, turn off Flash on Silent.