YouTube is the most accessible source for 5.1 Tamil video songs. Many channels upload "DTS" or "Dolby Digital" versions of popular tracks. 5.1 Tamil Songs Playlist
If you are looking for specific files to test home theater setups, these community-recommended sources often host high-fidelity tracks:
Here is a comprehensive guide on why 5.1 Surround Sound matters and where you can find the best Tamil musical experiences legally and safely. The Magic of Dolby Digital 5.1 in Tamil Cinema
Today, you have multiple options: