Sony WH-CH720N Help Manual page 76

Note
Depending on the ambient condition and the type/volume of audio playback, the ambient sound may not be heard even when
using the Ambient Sound Mode. Do not use the headset in places where it would be dangerous if you are unable to hear ambient
sounds such as on a road with car and bicycle traffic.
If the headset is not worn properly, the Ambient Sound Mode may not work correctly. Wear the headset properly.
Depending on the surrounding environment, wind noise may increase when the Ambient Sound Mode is turned on. In that case,
change the Ambient Sound Mode settings from Normal mode to Voice mode using the "Sony | Headphones Connect" app. If the
wind noise is still significant, turn off the Ambient Sound Mode.
Related Topic
About the voice guidance
Using the noise canceling function
What you can do with the "Sony | Headphones Connect" app
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