A common issue on a farm is keeping birds out of grain stores or livestock / cattle sheds. Animal feed typically attracts Starlings and Crows (often in large numbers) which can have a high cost in both loss of feed and the spread of disease.
There are two types of bird repeller. One is ultrasonic and is silent to humans. The other is the complete opposite and makes a noise which can be heard by workers (and anyone else living nearby.
The last thing any farmer wants is to induce stress in livestock. The ultrasonic units emit a high pitch sound which is possible might be within the hearing range of cattle. Importantly, the attraction of the grain to birds can sometimes be greater than the deterrent effect of an ultrasonic repeller.
The Multisound audible repellers however, can be heard by birds and cause no stress to cattle. The effect of the "noisy" repeller is instant. Turn it on and birds scatter. The downside is that because the audible repeller makes a noise, it's not suited to locations where domestic housing is nearby.
How does the Multisound audible bird repeller work? It plays digital recordings of other birds in distress or predators of a specific species.