The actor’s lips are moving on your television screen but the sound coming from the speakers doesn't match up, or there's no sound at all. The most likely scenario is that you’ve got a problem with the audio/video synchronization somewhere in your system. For Comcast cable subscribers, troubleshooting this issue starts with examining your set-top receiver and cables.
Reset Your Cable Box
Your cable box is responsible for picking up the programming signals sent out by your cable company. This set-top box, also known as a receiver, is linked to your account: it blocks you from viewing premium channels for which you haven't paid and makes sure you can view your subscribed channels. Sometimes, the receiver doesn't properly receive updates from Comcast and it must be reset. The steps for resetting your cable box depend on the make and model; but, generally, it involves unplugging the box from its power source for 10 to 30 seconds. When you plug the box in, it will automatically search for and download the latest updates from Comcast.
Inspect Your Cables and Connections
If resetting your cable box doesn't correct the audio sync issues you are having, inspect the coaxial cables and their connections to each device. The cables relay the signal from your cable company to your receiver and your TV. Any damage to these cables, or any loose connections, can degrade the quality of your audio as well as your video, resulting in conditions such as fuzzy audio, unsynchronized audio, pixelated images and choppy video.
Comcast May Not Be to Blame
Your cable provider and your hardware might not be to blame for audio issues. If you are using a high-definition receiver to view HD programming, a damaged or improperly connected HDMI cable between your receiver and television could be causing the problem. RCA cables, which transmit audio and video signals between standard definition receivers and televisions, are another potential source of trouble. If the red and white audio cables are damaged or incorrectly installed, out-of-sync audio could result. Even your TV itself could be to blame. Your television's T-CON or timing control board is responsible for synchronizing the images on your screen with the audio; if the audio and video are out of sync even when you watch non-Comcast programming, this could be the reason.
Audio problems on multiple televisions in your home suggest the issue is caused by something beyond your control. Because the cables located outside your home are Comcast's property, the company must maintain and repair damage to these lines. Additionally, Comcast customers do not purchase their set-top receivers; rather, Comcast leases them out. This means the boxes -- like the exterior cables -- are Comcast’s responsibility. If you suspect your cable box is defective or the wiring outside your home is damaged, contact Comcast customer support at 1-800-COMCAST to schedule a service call.