What ultrasonic frequency repels mice? - briefly
Mice are typically repelled by ultrasonic tones in the 20 kHz–30 kHz range, with many commercial devices operating at 30 kHz–65 kHz to encompass their hearing spectrum. Effectiveness diminishes above 70 kHz, as the frequencies exceed the rodents’ audible range.
What ultrasonic frequency repels mice? - in detail
Ultrasonic devices designed to deter rodents operate most effectively within the 20 kHz to 65 kHz range. Laboratory tests indicate that frequencies between 30 kHz and 55 kHz produce the strongest aversive response in mice, causing avoidance behavior without causing permanent hearing damage.
Key points for optimal performance:
- Frequency selection: 30–55 kHz, with a peak around 40 kHz, yields the highest repellency.
- Modulation: Pulsed or frequency‑swept signals prevent habituation; a cycle of 5 seconds on, 10 seconds off is commonly used.
- Intensity: Sound pressure levels of 90–100 dB SPL at the source ensure the signal reaches the target area; attenuation through walls reduces effectiveness dramatically.
- Coverage: Emitters should be placed no more than 1 meter apart in enclosed spaces to maintain sufficient intensity throughout the environment.
- Duration: Continuous operation for at least 48 hours is required for mice to associate the sound with an unsafe zone; after this period, the presence of the signal alone sustains avoidance.
Scientific literature attributes the deterrent effect to the mice’s acute hearing range (1 kHz–100 kHz). Frequencies above 20 kHz are inaudible to humans but remain within the auditory sensitivity of rodents, producing a discomfort response. Repeated exposure leads to stress‑induced avoidance, but prolonged, unvarying tones can result in acclimation, reducing efficacy.
Limitations include:
- Barrier penetration: Ultrasonic waves do not travel through solid objects; open pathways are necessary.
- Species specificity: Frequencies effective for mice may be less deterrent for other pests such as insects or larger rodents.
- Regulatory considerations: Devices must comply with local noise‑emission standards to avoid unintended disturbance to pets or wildlife.
When selecting a repellent system, prioritize models offering adjustable frequency settings, automatic sweep functions, and verified SPL output. Proper installation, regular maintenance of transducers, and periodic performance checks ensure the ultrasonic field remains within the effective range for rodent deterrence.