Letra de In The Mongolian Style Blues

If you are interested in the throat singing part then it is (kargyraa, and sygyt).
He is playing a Gnawa Bass (Gombri).
The deep voice he uses is achieved by speaking/singing in the deep kargyraa style. It is a combination of the false vocal cords, the tongue placement, pitch, and oral cavity shape, nasal/or not, chest cavity resonance. Things like that.
*If you are attempting it in earnest get informed. You can do real damage to your vocal cords if it is done incorrectly. A bad sore throat (vocal cords), or constant coughing is a sure sign of bad technique.
Like all musical instruments, it requires practice everyday.