The barking collar is a good idea but you have to do training concurrently to make it permanent. If you don't then the barking will continue once the collar is off. I have one for my dog but I'm still working with her to control her barking (more for when I leave the house). But the key is to not reward unwanted behaviours. If you know what causes her to bark, expose her to it and let her rip. Show him the treat and once she stops,. wait 5 seconds and then give her a treat. If she continues to bark before the 5 seconds is up, then don't treat her. If you give her a treat right when she stops, you are actually rewarding her barking. She has to associate the treat with her calm behavoiur. ONce you've successfully gotten to 5 seconds of peace, gradually increase the time. This will probably be a lot of work but it will be worth it. There is also a product which you put in a room and when the dog barks, it emits a high pitched sound which dogs can hear. Bit the dog may eventually learn to bark louder. I think the collar is the best idea.