The technology involved in repellent for aggressive dogs has moved slowly, but the Sound Defense represents a major improvement in the field. In the past, people have had to rely on primitive sprays or unpredictable ultrasonic devices to chase canines away, and neither were reliable in high-stress moments. Sprays can be carried away by wind and can produce inconsistent coverage. Ultrasonic devices have to be more precisely aimed due to the narrower beam spread and may not even be registered as a threat by the attacking animal. As a result, people have relied on intimidation methods to chase the animal away. This doesn’t always end well.
Fortunately, repellent designed for aggressive dogs is improving and now uses audible sound tones to scare attacking animals away. For a long time, the belief was that canines would be warded off by higher sound frequencies, but it’s now clear that there is a sensitive range of hearing that the canine is more alert to. Activating this sensitive range is more likely to provoke a response, and with the right combination of sounds, it’s possible to intimidate and annoy the animal into turning away. The effect is nearly instantaneous, requiring a second or so to take hold, and it’s simple to execute. With lower sound frequencies, the beam spread is wider and doesn’t have to be expertly aimed. With little time to react, this extra leeway may make all the difference.