Very old post, but I felt a need to say something. A male with a bass voice typically averages under 100Hz when speaking and down to a D2 when singing. It also should be noted, my average vocal frequency is 77Hz, although, I can sing without extended techniques down to an E1 (40Hz). The average vocal frequency of a person cannot be changed like some people earlier in this thread indicated; that is dictated by both the length and thickness of the vocal folds. Basically, you cannot speak with a frequency you are not capable of without using extended techniques; such as subharmonics or fry, which are nearly impossible to carry through all forms of phonation to create a vocal F0 (average vocal frequency).
