I want to connect motherboard sound output to my Home Theatre system using the optical audio output. But I also want the line-in audio to be audible. Why can't I mix the analog line-in with digital audio such as wave audio, MP3, CD or DVD sound? Is this impossible. I don't understand why this doesn't work. After all, it is possible to record the "line in" audio to a WAV file. Why is the sound chip too stupid to put the same audio on the digital output?