From Tejano to Mississippi hounds

Anyone own a silencer?...for the 3 dogs in my neighbor's yard who bark incessantly at nothing. Anything will work, including my neighbor getting off her couch and opening the door to let them in. Oh wait, there's a doggy door in her back door. So how are they not totally obnoxious to her? It's so bad that my Golden Retriever plastered himself against our backdoor begging to get in out of the noise. I am a dog lover...but these have to go.