Well that works. That sounds like the better way to do it...I have the misconception that no TV tuners have dedicated audio inputs...because mine's cheap and doesn't, and so I have to route all the sound to the Line In port
However, nice TV tuners will give you more audio inputs, so you won't have a problem. You might need DScaler though, TV Tuner audio inputs may show up in the Volume Control, you might have to switch input devices, but it might show up. Try it and see, if not, then use DScaler.