A while ago I had a custom scoreboard made in China. Unfortunately, they didn't provide a buzzer loud enough for us, nor any technical documents. This is the board + buzzer https://imgur.com/a/TXLPR. With my current knowledge I assume the board is wired with ground + power to the buzzer. My goal is to wire a 3.5mm female aux in so that I can run a Male/Male aux from that to a Speaker. My only concerns are that I don't know the impedance among anything else minus what I can get from a voltmeter. I'm a bit lost at how I should go about this so anything will help. I'll try to get the schematics but they never sent them. We told them what we needed for a scoreboard so they didn't send much but that.
The device in the picture is a dedicated 12V buzzer, not a speaker. If you replace it with a speaker, all you're going to get is a loud click at best. That might be followed by smoke from either the speaker, or whatever is driving it.
If you don't know the specifications of anything, it's probably safer to use the 12V output to drive a relay, which then switches on whatever you want to make the noise.