DIRECTIONAL emergency SIRENS LTD PRODUCER OF the patented UNIVERSAL 'QUADRASONIC'™️ DIRECTIONAL emergency vehicle SIREN SYSTEM
PUBLIC PERCEPTION - ELECTRONIC SIRENS
Most motorists have experienced hearing emergency vehicle sirens, but were unable to readily locate the direction the vehicles were travelling from.
• Electronic sirens often use rising frequency sounds which change continuously. The human psychoacoustic system has insufficient time to lock on to the sound because the frequency is constantly changing, often over a very short time.
• The high frequencies of electronic sirens bounce off walls and buildings with little perceptible change in volume or pitch. This makes it difficult for motorists to differentiate between the original siren sound and the reflected sound.
• Current sirens have a narrow sound beam projecting mainly forward but not to the sides. This makes them hard to detect, especially at crossroads - where the majority of accidents occur.
ELECTRONIC SIRENS - TESTING RESULTS
YELP! and WAIL! Sirens were introduced in the mid 1970's
A USA Government Sponsored Report in 1977 tested electronic sirens on people under 64. The results showed that the Wail siren's direction was able to be judged only about 41 percent of the time.
The yelp siren's direction could be heard just 17 percent of the time!
Wail and Yelp sirens continue to be used today with detrimental effects on the health and safety of the public and emergency services personnel.
A single Sine Wave siren scored 67 percent directional locatability.
* The Quadrasonic Siren System uses four Sine Wave sirens - Each housed in enclosures focussing and directing the sounds forwards and to the sides to maximum effect.
Electronic sirens are proven to have poor effectiveness. Fit Quadrasonic Directional Siren Systems for improved efficiency and safety.