macOS Help me get rid of this goat noise

So my roommate is a rather terrible person who somehow set my computer to play a goat noise every hour on the hour. I've tried to resolve the issue, but I've had no luck. I might normally find this funny, but I'm rather busy, and I can't deal with this B.S. right now.

He's rather technically savvy with Macs, and when I got home, Terminal was open, but it was just at the normal screen that it's at when you first open it. This leads me to believe that he's done some sort of programming stuff to make this happen.

I can't just turn it off in the clock settings in system prefs. The "announce the time" checkbox is unchecked.

My computer is normally locked down tight with my password, but I left it unlocked because I needed him to upload a file when it was done rendering because I had to leave the house. I guess I've learned my lesson not to trust him.

Any ideas on how to resolve the issue? I'm asking you programmers because I think he used some type of Terminal stuff to make it happen.

Thanks for all of the replies, guys!

As it happens, I just got him to undo it for me. He sat down and did something with Terminal, and that's that. I didn't really want to ask him, because I didn't want to reward the behavior, but that's that.

I appreciate the detailed solutions, though!

As an update, I've completely figured out the problem. It turns out that my roommate was just screwing with me, and wasn't actually fixing anything, and went along with the story of me accusing him of doing something.

I use Adobe After Effects quite extensively, and when a render fails, it makes a goat noise (just figured this out the other day). Now that's all good and well, but I wasn't doing a render when it made the noise. I use this product called BassJump with my iMac, and sometimes, it'll just spit out random short bits of audio, which is probably some sort of software bug.

So, my BassJump held on to that goat noise from an earlier time, and spit it out. weird stuff.