being uncool anyway I don't have to worry about such things, I have degressed to one of those dingers as opposed to a proper ring ring bell. my mountain bike sports a compass on top which has come in usefull when lost in the woods.
I rarely use it , but like my seat belt and airbag in the car or horn or fog lights , I rarely use those too (or the jack and spare tyre) but I would sure miss them if they weren't there when I did need them.
my main quarry is horses, - they got nuts if you just swish by them from behind, and an upset horse is liable to jump on you or dump the rider on you , so I don't pass until the rider is well aware, so several dings as I approach ussually works, I would shout but going uphill I would be lucky to get a desperate croak out !
Maybe its me (hearing has been impared by a history of load bangs) but I cannot hear bikes coming up from behind me, they scare the s-t out of me when they just appear on your elbow. If I ever overtake anyone I have vowed to give them a ding first - but it is yet to happen.