There is so much misconception among HMs, BBBOTS panellists etc about the traits of an Alpha. They should watch Monkey World or Monkey Life to get a proper understanding of group dynamics.
An established Alpha is frequently a quiet individual seemingly on the periphery of a group. They have no need to be loud or aggressive because their authority is established and the group treat them with deference and respect without them having to lift much more than a finger.
Those scrapping and forcing their will tend to be lower order beasts who are still having to fight for their place in the pecking order. They maybe Alphas in the making but have not yet earned the position of respect which enables them to dominate by their very existence.
The last true Alpha I can remember (there may have ben later ones but I can't think of one off the top of my head) was the footballer come actor chappie. He rarely raised his voice, he just presided over the others and they pretty well (with a few exceptions who didn't last)) deferred to him. The house was pretty peaceful most of the time too. Only came third though.