Now, you don't want to discourage him if someone is at the door or breaking in, so you must use it sparingly. Try it, and I think you'll find he'll get the message.... Just a suggestion and hope it doesn't turn him into a "Natural Born Killer"... LOL.
Good luck.
That was the technique I used in training my Springer pups. I used to hide, allow each of them to bark only TWICE in response to noises and after that they got the water spray in the mug. Worked on every one of them.
I would hire some rougher looking and smelling somewhat distant teen friends of some family members to play the roles of intruders.
When there were noises not in the house and not at the door of the house nor close to the windows of the house, shout NO!
Spray bottles on stream are also good to pair with the NO! as well as alone.
After the dog has begun to show good learning of not barking at more distant sounds, introduce the paid 'intruders.' If the dog does NOT bark at them--you can bark as much like a dog as you can manage and leap at the door barking until the dog joins you.
THEN
shortly thereafter, have another hired or friendly assistant make a more distant but detectable noise. Perhaps timing it with trash delivery etc. If the dog barks THEN, shout NO and squirt; zap etc. into silence.
Give the dog 8-48 pairings of the 2 conditions. At first--make them all one or ther other several times straight in a row. Then start mixing them up randomly.
Of course, some dogs like some people
are REALLLLLY DUMB, DENSE. They just are unable and/or too stubborn to learn such fine discrimminations.
IN such cases--send the dog to doggie heaven; move back to the country; give the dog to a loving farmer; . . . or some such.