Hello eelay,
Welcome to the Canon Forums and thanks for your post!
Based on the description of the issue it sounds like there could be an problem with the speaker of the camera. If you transfer the video you mentioned to a computer, does the sound play fine when watching the video?
As a general troubleshooting step you may want to go ahead a reset the camera to the default settings to see if that makes a difference. Please follow the instructions below.
Settings Reset
1. While the camera is on turn the mode dial to "P" (Program mode), which allows all menu options to become available, then press the menu button.
2. Move across the top of the menu to the last wrench tab. (Yellow tabs)
3. Go down the menu list to "Clear Settings" and press the Set button.
4. Choose "Clear all Camera Settings", and press the Set button.
5. To complete the reset highlight "OK" and press the Set button again.
6. Next, move over to the Custom Functions menu list.
7. Reset the "Clear all Custom Func." settings as well.
Power Reset
1. Make sure the camera is off, and then remove the battery, memory card, and lens.
2. Close the battery/memory card doors.
3. Turn the power switch to the "ON" position, and then press and hold down the shutter button for 10 seconds.
4. Release the shutter button, turn the power switch to the "OFF" position, reinsert the battery, memory card, and attach the lens.
5. Power the camera on.
If you continue to have issues with sound playback after these steps I recommend contacting our Technical Support for further assistance. Please CLICK HERE to reach our friendly Technical Support Team by phone or email.
