Timelapse Videos Have No Sound
If you've implemented timelapse using the Speed feature, you’ll notice that audio is off by default. As your video is accelerated with this feature, the audio would also be accelerated, causing a distorted audio track.
Turn Ring/Silent Off
When your phone’s mute button is toggled on, it will mute sounds and alerts. Toggle audio back on and play the video again to hear its audio.
Turn The Volume Up
Your phone's volume level might be too low. Try increasing its volume and play the video again.