I was thinking about heading to a place where there is a chance to confront a coyote. It worried me a lot then..this question popped up.
If I have big enough speaker that can play sound of coyote's predator, does it help?
Not a silly question at all and surprisingly easy to answer: yes!
There are even sound-systems exactly for that use.
Try sound. Sound can have an excellent impact on a coyote that has wandered into your yard or campsite.
Try banging trash can lids or anything else that is noisy to scare the coyote off.
Yell and make a lot of noise in any way possible.
Motion activated alarms can be useful. An even more tech-savvy option is the new Anti-Coyote sound system. This system relies on the fact that cougars occasionally kill coyotes. The systems emit replicated cougar sounds, and may keep coyotes away.
Propane exploders can be used to deter coyotes on farms and ranches.
The USDA’s Denver Wildlife Research Center developed a frightening device called the Electronic Guard (EG). The EG consists of a strobe light and siren controlled by a variable interval timer that is activated at night with a photoelectric cell. In tests conducted in fenced pastures, predation was reduced by about 89%. The device is used in Kansas and other states to protect cows/calves from coyote predation. Most research on the effectiveness of this device, however, has been done on sheep operations. Suggestions for using the unit differ for pastured sheep and range operations.
So, it's more important that you even make sound in the first place than what sound it is. But as you've the choice with your speaker setup, you should either use Wolf, Mountain Lion, Bear or Cougar sounds as they are the most dangerous predators (in this order) for coyotes.
Don't forget to checkout this pdf:
Coyote-Activated Frightening Devices For Reducing Sheep Predation On Open Range
Summarized list of additional steps to take according to Wikihow:
A good method to get rid of coyotes is to use a coyote shaker — a soda can filled with pennies or pebbles and sealed with duct tape. This device scares the approaching coyote in three ways. Through:
Shake or throw this “coyote shaker”.