Neighbors Using Sound Machine to Keep Cats Out is It Safe?

Hi, so I think my neighbors are using a sound machine to keep ny small cat colony out of their yard. I dont mind as long as its safe. I live in Brooklyn so the yards are all connected only seperated by a wire fence. They are right next to me. I noticed the cats go crazy a few times. I had purchased them a motion activated sprinkler but since its winter they dont have it set up.

Does anyone have experience with these or know if they will drive my cats out? I only have 3 at the moment.

I've never heard of a machine like this.  The ones I found through google do not seem to be able to blast through fences.  They would thus only work if your cat was on your neighbors property, unless your neighbor has installed it on top of the fence, which seems like an awfully cruel "solution" to the problem.  If so, you may be able to point out it will keep the cats out of their yard better if it is placed in their yard.

Maybe there is a way to keep the cats out of their yard without this machine.  

Cat proofing the top of the fence is an idea.  There are commercially available models but you can also nail a length of wire fencing along the top of the fence.  Bend it into an upside down "U".  The cats won't like it when it bends under their weight and will avoid it.

Or maybe you can also fence off a section of yard, with a wire roof, to keep the cats confined?

Hopefully, you can work with the neighbor.  Its tough when they make it so hard, though.

They have it in their yard but since the fence is wire and open it was going off when I walked through the yard. They now turned it a different direction so its not doing that.

I have thought about the cat fencing but its hard for me since I rent and the current fence is pretty low so it would require a lot of work and money on a property that isnt mine.

At the moment it seems like the noise no longer bothers them. At first it was freaking them out but now it seems likes they have gotten used to it. Its kind of annoying and goes off even when they arnt in the yard. I think its sensative to wind and small birds etc.

If it works I am all for it. I would love it if the cats only stayed in my yard. But they go all over. One of the younger ones this morning popped up on the roof on top of a garage behind me. They climb like crazy.

Ill see what happens with the sound machine. I just dont want it to hurt their ears and cause damage.