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How to use The Big Cheese Rodent Repellents

The STV rat and mouse repellents are speaker units which have been designed to emit sound at very high sound frequencies beyond the range of hearing (humans hear up to about 25 kHz, ultrasonic speakers emit sound up to 60 kHz), so as far as people are concerned the ultrasound units appear silent when operating.

Blocking the chatter

Rats and mice are often prey to larger predators; they are in constant sound communication with each other at lower frequencies which let individual mice know that all is well with other group members – but if alarmed by a threat or in distress, they will emit a high frequency alert call.

Ultrasound units work by drowning out the rodent communication sound, which means individuals lose contact with each other and cannot hear any alarm calls. In practice rats and mice quickly learn to avoid ultrasound-protected areas.


Very high sound frequencies do not travel very far; one way to have further reach is to utilise STV ultrasonic units with larger, more powerful speakers (suitable for large rooms). The other way is to buy a three pack of smaller units – each will have more limited range but together add up to useful area coverage (ideal for more complicated room shapes).

Positioning of ultrasound units

In practical terms very high frequency sound only travels in straight lines – place the ultrasound units so they are directly facing into the area to be protected, and plug into an electrical socket near to the ground. Areas which are around a corner, or behind furniture or furnishings (like long curtains), will not be ultrasound protected. Plugging in an ultrasound unit into kitchen counter level sockets will protect the worktop, but leave a ‘sound shadow’ immediately below at floor level.

Rats and mice prefer to travel along the join of the floor and wall, rather than across open areas, and will use doorways to enter a room. STV ultrasound units can be used to best effect protecting doorways and disrupting travel routes.

Rodent removal

Please think of STV ultrasound units as rodent repellents, they offer area protection and do not kill. This means rodents will be pushed to other areas, not eliminated completely.

To control rodents, use the ultrasound units to protect areas, along with environment controls: think in terms of shelter + food + water. As it happens, rodents obtain most of their water from food, so denying rodents shelter and food is usually effective. Keeping food in containers and off the floor removes a major source of attraction; having a good tidy up – especially at floor level - removes shelter. Sealing off gaps and cracks around the outside of your property prevents entry, and if the bottom of the external door is not close fitting, the use of brush strips is most useful.

Rodent pets

Do not use sonic repellent units around rodent pets such as hamsters, gerbils, guinea pigs, rabbits etc. Rodent pets are best removed from rooms which are being ultrasound protected.

- Steve Wright, Product Standards Manager, STV

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