If you play a 5.1 song and hear the instruments but not the singers, your center channel is likely off. Ensure your speaker configuration in your OS (Windows Sound Settings) is set to "5.1 Surround" and not "Stereo."

Isaignani Ilayaraja | 90's Tamil Hit Songs | DTS (5.1 )Surround

Purists will correctly point out that a standard . It only carries a left and a right audio channel. So, what exactly are you downloading or streaming when a file is labeled as a "5.1 fixed MP3"? 1. The Stereo-to-Surround Upmixing Process