Talking is free, weighs nothing and works quite well. The upside is you can turn it off when you've got good sightlines or things are otherwise low risk. The downside is that I sometimes get lost in my thoughts on a solo hike and don't start yakking it up when I should. My wife is much better at noting the confluence of poor sightlines, berries, and background water/wind noise and she consistently starts calling out in those settings. Numerous times, we've crested the rise or turned the corner to see the bear already heading away.
This reminded me of a Japanese documentary on cultures around the world where divorce rates are extremely low or nonexistent. One area in Indonesia where the populace lives in longhouses, with huge extended families all under one roof and considerable problems with tension between people, has an old tradition of requiring that a husband and wife, each afternoon, head out together to hunt for food. Though the hunting for food is not entirely necessary, the activity of cooperating in a dangerous place (lots of big wild animals like tigers), calling out to one another to ensure each other's safety and for finding food, so that they are truly reliant upon one another for survival, seems to work very well in daily reminding the couple how they are dependent upon one another and each person's presence remains meaningful.
In China there is an area where, whenever something important or momentous needs to be discussed between spouses, they are required to sing it. The singing forces them to be mindful of what and how they are saying what they need to say, plus forces the speakers to control their anger.
Here in Japan all train engineers and conductors and platform conductors are required to speak out in a falsetto voice (either higher sound, or purposefully more nasal) and indicate with their hands any safety concern, including pointing and sweeping the hand along the line of the platform up toward the front of the platform, singing out what controls they are moving or changing in the driver's compartment, announcing the opening and closing of doors, checking the platform camera and CCTV, and ringing the set off bell. By requiring expressing what they are seeing and doing they stay focused. The accident rate, while not perfect, is extremely low compared to other countries. The Bullet Train has never had an accident in its 50-year history, with over 4 billion passengers transported (151 million passengers a year). That's pretty impressive!
Anyway, I sing quite a lot when I'm hiking. Here in Japan you have Asian Black Bears which are mainly shy like those in North America and up north the Brown Bear, which is a cousin of the Grizzly. You also get WIld Boar and Snow Monkeys which can be very aggressive. I've often come face-to-face with Wild Boars (especially at night) and Snow Monkeys and usually the singing is enough to deter them. Like in the popular tourist spots in Yosemite, the habituated Snow Monkeys are the worst. They can't kill you, but they sure do a good job of scaring you!