Where I ride my bike has a large paved path all the way around it for all foot and non-motor traffic.
Normally I just call out what side I am coming up on other folk, despite 75% of them not knowing their left from right.

I grow weary of calling out, but I don't know if I want to be "the jackass with that electronic horn" just yet. Everyone seems startled when I call out to them, so why not have it be a jarring-affront-to-nature sound?
https://www.youtube.com/watch?v=31eJmmmpQL4

What is worse? Just having a biker blast past you on your left or right without you knowing? Having them call out to you constantly? Cold robotic sounds?