Use the Control Panel to check your default audio device and its volume setting. Set your preferred device as the system default sound playback device, and then verify that its volume is not muted or set low.
Your computer could have more than one device that can play back audio e. If you do hear the tone, then go to Sound is missing from some clips. If you do not hear the tone, then go to Sound is missing from all clips. Click the Play button in the Source Monitor or play the clip from Timeline. The Bars and Tone clip opens in the Source Monitor. In the Project panel, double-click Bars and Tone. Perform the following steps which create a test clip of color bars with a 1-kHz tone to determine which clips are missing sound during playback.