1) Verify that the minijack-to-RCA audio cable is connected to the proper audio input, AUD-1 or AUD-2 on the DualTV card. For example, if you are using SVID-1 to record video, make sure the audio cable is plugged into the AUD-1 input. Please note that this tip does not apply if your video source is connected to the CATV input.
2) Your speakers may not be connected and/or your volume is too low. Make sure the proper cables are connected to the sound card and the volume is set to a level that you can hear. Also, please check to ensure that your sound card's volume and wave control is not set to "Mute."
3) Verify that the TV audio settings in MCE is NOT set to"SAP"(Second Audio Program).
4) Make sure your sound card is using the latest drivers which you can download from their web site.
5) Verify that you have the latest Microsoft DirectX components. Click here to upgrade it.
6) If you are using a set-top box, please verify its volume control is not set too low or muted.