Take him to the vet. See if something is wrong. How much exercise is he getting? Tired dogs aren't as reactive.
Are there some good , positive obedience classes you can go to ? Barring any medical reason he might just be feeling very insecure. Changing homes at this time in his life is probably very confusing and scary. Classes will help build trust and a trainer can give you advice. Just dont use punishment like loud noises and spray bottles. If its insecurity, it will just make it worse. Distractions like doing tricks etc, will likely be better.
My corgi is a barker! I adore this dog, but, oh! that corgi bark! Pierces right through your head. At least beagles sing.