An ultrasonic dog repeller may be a popular form of canine deterrence, but it isn’t the most effective, or the easiest to use. This technology emits extremely high frequencies of noise that are beyond human hearing. They are, however, within the hearing range of canines, and the idea is that the higher the tones, the more annoying and repulsive they are to the animal. This theory has never been officially tested, though, and there is reason to believe it isn’t true. What is true is that canines are more sensitive to certain tones, and this is what newer technologies seek to take advantage of and hone in on.
There are two major problems with an ultrasonic dog repeller. For one, there’s no telling when the device is actually working, as humans can’t hear it. It’s possible, even with some kind of indicator, that the device isn’t producing a single sound when activated. These devices are also difficult to aim, as they emit in a narrow angle. When under attack by a rushing canine, this can be a serious liability, and it might be part of the reason why these devices can be less effective than those that use audible tones.
Audible sounds, if used in the right frequencies and patterns, are more likely to repulse the canine and are much easier to aim. When facing down an aggressive animal, this can make the difference between walking away unscathed, and not walking away at all.