Tamil film music is known for its complex layering. A.R. Rahman’s tracks, in particular, are famous for using diverse instruments and ambient sounds that often get "flattened" in standard MP3 compression.

In a 7.1 mix:

(Include standard references on MP3/MPEG Surround, binaural rendering/HRTF, surround mixing practices, and studies on perceptual evaluation of spatial audio.)

Since your request is quite broad ("give me an paper"), I have interpreted this in two ways. First, as a technical overview/white paper explaining the technology and challenges of 7.1 Surround Sound in the context of Tamil MP3 songs. Second, I have provided a guide on how to find or create such files, as true 7.1 MP3s are technically rare.

Don't have a native 7.1 file? Most modern AV Receivers have Dolby Surround Upmixer or DTS: Neural X. You can feed a high-quality stereo MP3 (320kbps) into the receiver, and the chip will "fake" the surround sound intelligently. It doesn't match native 7.1, but for old classics like "Sundari Kannal", it brings them back to life.

Example mix bus layout (conceptual):

Example send routing:

If you have the hardware (a home theater system or high-end surround headphones), these tracks are essential testing grounds for 7.1 audio: