You select the sound card to use for recording in these lines:
Code:
    Set SEnum = DX.GetDSCaptureEnum ' get the device enumeration object
    
    ' if GUID is empty, then assign the first sound device
    If Len(GUID) = 0 Then GUID = SEnum.GetGuid(1)
    
    ' choose the sound device, and create the Direct Sound object
    Set DISCap = DX.DirectSoundCaptureCreate(GUID)
Just change the 1 to 2, or you can display the list of the enum items in a drop down so that the user can select the sound card to record from the application.