This is a dedicated ringtone repository. Search for "Sundarapandian." They offer a clean 320kbps MP3 version trimmed to 35 seconds. No login is required, and the download button is clearly visible.
Simply search for the Sundarapandian BGM ringtone on your preferred platform, select the version you like, and download it to set as your ringtone! sundarapandian bgm ringtone download
Since iPhones require .m4r format, follow these steps: This is a dedicated ringtone repository