The Mosquito or Mosquito alarm is a machine used to deter loitering by emitting sound at high frequency. In some versions, it is intentionally tuned to be heard primarily by younger people. Nicknamed "Mosquito" for the buzzing sound it plays, the device is marketed as a safety and security tool for preventing youths from congregating in specific areas.
The latest version of the device, launched late in 2008, has two frequency settings, one of approximately 17.4 kHz[2] that can generally be heard only by young people, and another at 8 kHz that can be heard by most people. The maximum potential output sound pressure level is stated by the manufacturer to be 108 decibels (dB) (comparable in loudness to a live rock concert) and the manufacturer's product specification furthermore states that the sound can typically be heard by people below 25 years of age.[1] The ability to hear high frequencies deteriorates in most humans with age (a condition known as presbycusis), typically observable by the age of 18.[3]
- ^ a b "The Mosquito MK4 Anti-Loitering device – Key specifications". Compoundsecurity.co.uk. 21 February 2008. Archived from the original on 2 February 2017. Retrieved 1 February 2017.
- ^ "MP3 sample of the 17.4 kHz tone". Archived from the original on 9 November 2020. Retrieved 21 June 2009.
- ^ Education.com (23 May 2013). "Sonic Science: The High-Frequency Hearing Test". Scientific American. Archived from the original on 24 October 2017. Retrieved 25 May 2017.