consider the word 'growl'. its an onomapoetic noun. consider how you move your mouth and your tounge in your mouth when you say the word. the clue for how to make this sound is the 'o' and the 'w' in succession, the 'g', 'r' and 'l' are fine tuning and harmonic details which you can get in later. so do it, say 'ow', make your voice real low and say it slow, like in the tunes.