Check in the Aardvark control panel under Advanced, ASIO and DirectX that the Master Aark Card is set properly to the card which is set to internal clock. You will need to exit back to the main Aardvark control panel and select all other cards in your system and check to see the Master Aark Cards are all set to the same card. Otherwise, the cards can function mostly independently and audio will not work correctly from a single audio application.