StarTrekFan says on 10/Sep/11
On DS9 he always appeared to be a bit shorter than DS9 Cmdr Sisko. He was always noteworthy for his stocky size. Star Trek seems to make use of several actors that you will frequently see but never hear. In this case I can see why beacuse they would have had to come up with some sort of concept to explain his unaturally deep voice.

joeylater says on 22/Apr/11
I worked with Kevin for years back home in D.C., and waaaay before he decided to leave Howard U and try Hollywood, and trust me when I tell you, that's his natural voice. It was deep then, and it hasn't changed a bit!