On the topic of bells and other devices , I think the voice is better because it can be adjusted to suit. Airzound is not something I'd use. But occasionally - peds don't know who or what is around them - no amount of calling out will alert them. Those ones I slow down to walking pace for.
Funny enough, if I'd not called out to warn her, I would have got past without any accident.

Worst thing is seeing other people out riding, I miss that!