A voice so deep, that whom ever has it can sing the brown note
(a note so deep, it makes you poop yourself).
Originated in the whom of the mother of the deep voiced person. Known not to be fully functional until about the age of 14. Also, the posseser of the voice is usually always pestered to read various things because of their deep and amazing voice.
Hey guy, you have a brown voice.
Yeah, because I just shit myself when you said "really"