The mahakala ritual chant in the listening guide is an example of what type of vocal performance?

In the Listening Guide, the Tibetan Buddhist monks perform sustained sections of chant called dbyangs in the Mahalaka Ritual chant.

Dbyangs are a type of vocal music that is performed by Tibetan Buddhists. Dbyangs are preserved sections of chants, which may have different kinds of versions that cater to different masters and sects, among others.