On Friday, October 23, 2020 at 2:15:46 PM UTC-4, T i m wrote:

I'm, confused. I asked about one of those (Electro-Acoustic
Transducer) on eBay, if it was a speaker or if it produced a noise on
it's own, just with a supply voltage etc and they replied it was just
a speaker, requiring external driving (assuming I'm seeing what you
intended on the link)?

Is the doorbell mechanical, with a coil and contacts that open and close? If so, a speaker in series would make noise from the interruptions in current flow. It might be loud enough for your needs. The only way to find out is to test it with any old speaker that you have laying around.