How is Ben with loud noises usually? Like hair dryer, or hoover or even tv and radio?
My two dont like my dog barking, but they normally address the noise as a warning-like when someone thumps a foot, they sit up check there is no danger and then continue on with what they are doing.
It took Yumi ages to get used to my hedgehogs though, they freaked her out something awful. I found that reassurance was key.
Try just rubs til he’s calm reinforced with a treat. She still has no idea what they are or their purpose.
What MoxieMeadows says is also really good advice. Other noise from a radio will maybe help push the dogs noise into the background for him.
Alternatively treat the source of the problem and actively discourage the dog from barking. Fill a spray bottle with water and spritz the dog when it barks-it wont hurt it, it’s just a good deterrent.
We used this with a dog that’s owner was getting noise compliants and it worked really well.