Thanks for you reply.
We have tried everything for years, from the ole pennies in a can, to spray bttles, to shock collars. {I am ashamed to confess}

Not sure of his demeanor while screaming. Seems like just excitment from seeing someone, wanting attention perhaps. However, if it is a larger dog, he has been known to bust loose and begin fighting, even though he is only about 12-14lbs. Does not show any signs of fear.

Any situation where there is new people, other dogs, is when this always happens.