Distance matters when faced with an aggressive dog, and effective range is influenced by the sound frequency being used. An ultrasonic’s sound wave will travel a shorter distance than a lower frequency sound wave because an ultrasonic sound wave has many more vibratory cycles over time and distance than the lower frequency sound waves, like those of the Sound Defense. Ultrasonic sound uses up its energy faster due to the increased number of cycles of vibration it needs to create the sound waves of ultrasonic sound. The higher the tone, the more compact the waves, the more energy is required to move the vibration through the air. The more energy needed to move the vibration through the air, the quicker friction acts on the sounds wave, reducing its energy and amplitude. emit high-frequency tones. These ultrasonic sounds lose their energy faster as the sound wave moves through the air. As a sound wave’s frequency increases, the distance it will travel decreases, and its amplitude will decrease at a quicker rate. Lower frequency sound, like tones found in dog’s sensitive hearing range, will go further and won’t decrease in amplitude as quickly as an ultrasonic sound wave. The further the signal can travel and the longer it maintains its power, the better. When dealing with an aggressive dog, distance matters. The Sound Defense emits a signal with frequencies in dog’s sensitive hearing range which are far lower than the frequencies emitted by a high power ultrasonic dog repeller.
But, it's a known fact that dogs hear high frequencies
Ultrasonic Lawn Garden Cat Dog Repellent
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LOUD DOGS / STUPID NEIGHBORS / HIGH FREQUENCY SOUND ..
This means that conduction occurs through the complementary pairs of TR1/TR4 and TR2/TR3 on alternate marks and spaces, effectively doubling the voltage across the ultrasonic transducer, LS1. This is optimised to generate a high output at ultrasonic frequencies. This configuration was tested by decreasing the frequency of the oscillator to an audible level and replacing the ultrasonic transducer with a loudspeaker; the results were astounding. If the dog repellent circuit was fed by a bench power supply rather than a battery that restrict the available current, the output reached 110dB with 4A running through the speaker which is plenty loud enough!
Why I'll Never Use Ultrasound Dog Deterrents and Repellers - Dogster