Most modern DACs like the DAC2 have a HT bypass input.
You can hook the Onkyo's preamp output to the DAC2's HT bypass input.
The DAC2 then feeds the power amps.
When you are listening to 2 channel sources, use the DAC2 (with your digital sources feeding the DAC2).
When you are watching a movie, switch the DAC2 to the HT bypass input, and the Onkyo will play the left and right channels through it (at unity volume gain) to the L and R speakers. You may need to run Audyssey again on the Onkyo to ensure the volume levels are set correctly.
You can hook the Onkyo's preamp output to the DAC2's HT bypass input.
The DAC2 then feeds the power amps.
When you are listening to 2 channel sources, use the DAC2 (with your digital sources feeding the DAC2).
When you are watching a movie, switch the DAC2 to the HT bypass input, and the Onkyo will play the left and right channels through it (at unity volume gain) to the L and R speakers. You may need to run Audyssey again on the Onkyo to ensure the volume levels are set correctly.