How to use the Noise app in watchOS 9

The Noise app in watchOS 9 is a health feature designed to help protect your hearing. It helps users understand the sound levels in environments such as concerts and sporting events that could negatively impact hearing. 

As the sound levels change, the app’s decibel meter moves in real time. The watch can send a notification if the decibel level reaches 90 decibels, which can begin to impact hearing after four hours per week of exposure at this level, according to the World Health Organization.

By default, your Apple Watch will warn you when your average sound level over a period of three minutes reaches or exceeds 90 decibels. When that happens, you’ll feel a gentle buzz on your wrist and an alert will pop up on the smartwatch display. You can tap the notification to open the Noise app for details.

To set up the Noise app:

1. Open the Noise app (its icon l looks like an ear) on your Apple Watch.
2. Tap Enable to turn on monitoring.
3. To measure the environmental noise around you in the future, open the Noise app or use the Noise complication.

To get noise notifications:

1. Open the Settings app  on your Apple Watch.
2. Go to Noise > Noise Notifications, then choose a setting.

You can also open the Apple Watch app on your iPhone, tap My Watch, then go to Noise > Noise Threshold.

To turn off noise measuring:

1. Open the Settings app on your Apple Watch.
2. Go to Noise > Environmental Sound Measurements, then turn off Measure Sounds.

You can also open the Apple Watch app on your iPhone, tap My Watch, tap Noise, then turn off Environmental Sound Measurements.

(This how-to is based on my experiences and info on Apple’s support pages — where the images sometimes come from.)