Smith & Wesson... works for me!
I have 2 Rotties and a GSD, when I opene the door the Rotties bark, Max just goes ape-shi*, while Hannah tries to get out the door. Dirk my GSD does not growl bark or anything, he is just huge (114 lbs and 28 inches at the shoulder according to his last Vet trip)
It is funny to watch the door to door types who ring our door bell bsck off the porch and head down the driveway with out even trying to talk to me.