What does the ultrasound sound like that is used to repel mice? - briefly
It emits high‑frequency tones above human hearing, usually between 20 kHz and 70 kHz, perceived as a rapid series of clicks or a continuous high‑pitched whine.
What does the ultrasound sound like that is used to repel mice? - in detail
Ultrasonic mouse‑deterrent devices emit sound waves whose frequencies lie well above the upper limit of human hearing, usually between 20 kHz and 65 kHz. The signal is generated by piezoelectric or ceramic transducers that convert electrical pulses into pressure variations in the air. Most products employ a continuous‑wave (steady tone) or a rapidly pulsed waveform; pulse rates often range from 10 Hz to several hundred hertz, creating a pattern that prevents habituation in rodents.
The acoustic pressure level at the source typically measures 80–100 dB SPL (sound pressure level) referenced to 20 µPa, decreasing with distance according to the inverse‑square law. At a distance of one metre, the level drops to about 55–70 dB SPL, still sufficient to be detected by the mouse’s highly sensitive auditory system. The sound is characterized by a narrow spectral bandwidth centered on the chosen carrier frequency, with minimal harmonic content, which reduces the likelihood of audible leakage for humans.
Mice perceive the ultrasonic tone as a sharp, high‑frequency chirp that interferes with their communication and startle reflexes. The rapid rise and fall times of each pulse produce a clicking sensation that can be described as a series of brief, high‑pitched snaps. Because the frequency exceeds 20 kHz, the signal remains inaudible to most adults, though some children and teenagers with extended hearing ranges may hear a faint hiss.
Device specifications commonly include:
- Frequency range: 20 kHz – 65 kHz (adjustable in some models)
- Output power: 80 – 100 dB SPL at 0.3 m
- Waveform: continuous or pulsed (10 – 500 Hz pulse repetition)
- Coverage area: 10 – 30 m², depending on placement and obstacles
- Power source: mains‑connected or battery‑operated, with automatic shut‑off after a preset runtime
In summary, the ultrasonic emission used for mouse repellent is a high‑frequency, high‑amplitude acoustic wave, either steady or pulsed, that remains beyond human auditory perception while delivering a startling, disruptive stimulus to the rodent’s auditory system.