Re: Holy mother-of all!
That pipe look Great. I suspect you will have to look for something like the baffle to a Whizzer. Or you could look for what we used to call a Snuff or Not, I think they are selling them again. It looks like a washer with a small stem off the side, you drill a hole in the pipe near the end and put this device in the megaphone and then you can Snuff or Not. LOL. You turn the little handle and it puts the washer in the way of the flow of the noise, or not. Have fun, Dave
PS: I have an old one I will try and get a pic.