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What are the Different Sounds a Police Siren Makes

Posted by Extreme Tactical Dynamics on Nov 12th 2019

The role of police sirens is crucial. It’s to call the attention of both pedestrians and drivers and to make them aware of police vehicles on the road. As such, they can make way as needs be, and are used in a variety of both everyday and emergency situations. In an emergency, they are vital for clearing the road and hearing the sirens on the way should tell pedestrians not to cross the road, as a police car is coming. 

Meanwhile, a more day-to-day use is using a quick burst of the siren speakers to indicate to a driver that they are being pulled over and need to come to a stop. Those are not the only uses of the siren, however, and we will look at how and when they are used.

There is more than one kind of police siren

To the average person listening, the different sounds of police sirens might not be all that noticeable. It’s nothing but noise to them, after all. However, to the police operating those sirens, the differences between those noises are not only noteworthy, they can be important. There are different siren noises for different purposes and situations.

Below, we’re going to describe the different siren sounds, how they’re used, and why the police will sometimes use one over the other or alternate between different ones.

The different types of sirens

It’s worth noting that technically there is no distinction between individual sounds. Yes, there are recognisable different sounds and you may have seen people debating over whether “nee-nah” or “woo-woo” should the siren that police use most regularly. However, the police officers will change what siren is used as necessary, depending on the situation, and there are a few different notable types.

Yelp

This is a sound that rapidly alternates between high and low sounds, as is one of the two commands most readily available on the majority of siren command boxes. It’s often used in conjunction with rapidly flashing emergency lights to quickly grab the attention of drivers ahead of the car. In most cases, it means “pull over”, and the shorter yelp (compared to the longer wail) is often used in urban areas. This is because the short bursts of sound are thought to bounce off walls better, making it easier to hear in cities.

Wail

Like the yelp, the wail alternates between high and low notes, but it does it as a much slower pace. It’s another of the commands that is regularly used on most siren command boxes. Again, it’s also usually used with the flashing emergency vehicle lights. Compared to the “woo-WOO-woo-WOO” sound of the yelp, the wail is a longer, more drawn out “whhooooooooooOOOOoooooooooo” that goes from lower to higher to lower again. This sound is often used in rural, emptier environments, where the longer, drawn out sound is able to reach out better and is not as well suited to city use.

Hi-Lo

The hi-lo is very distinct from the yelp and wail sirens. It doesn’t have a “woo” sound to it, but is rather a “ee-oo-ee-oo” sound that’s not as rapid or as urgent sounding as the others. It’s also known as a “European style” siren, as it is often used by emergency services on that continent. The hi-lo is often used for the same purpose as the yelp and wail. However, it is used less often.

Furthermore, the three different siren functions on most control panels are also useful for situations where there is more than one emergency vehicles on the road. This lets pedestrians and drivers know there are several vehicles on the road that they should be aware of, even after the first one or two cars passes.

Power Call

The power call is a siren noise that is much more seldom heard than the three mentioned above. It is a monotonous “woo-woo-woo-woo-woo” sound that does not change in tone or pitch as it goes. It is not as frequently used simply because it was the first electronic siren call ever made, and has since been replaced by the wail, yelp, and hi-lo sounds.

Air Horn

The air horn is a long, piercing sound that rises quickly in tone and volume, then slowly descends and gets quieter again. It’s not used as often as the other sounds on the modern siren control panel, but some cars do still find use in having it outfitted. For one thing, it’s not an electronic sound like any of the others mentioned here, but is pneumatically powered. As such, if an electronic system is not working for some reason, the air horn would still be able to be used. Furthermore, it’s a very distinct and noticeable sound, so it’s still effective as a siren.

Piercer

This siren might sound a lot like the yelp on first hearing it. Indeed, it has much the same purpose, as most police siren operators believe it’s more effective in smaller, urban spaces and especially in heavy traffic. However, on closer listening, it’s much faster, and sounds a lot more urgent as a result. Again, it can be used if other cars on the road are already using a yelp, helping the user’s vehicle stand out.

Howler

The howler sounds a lot like the wail, but the lower notes on this siren have a distinct sound playing beneath the primarily note. This is a low-frequency sound that has been designed to be felt by vehicles directly in front of the police car. As such, it’s thought to be especially useful in clearing a way through traffic during a high-speed pursuit or emergency. Since the drivers can both hear and feel the siren, they can move out of their way more easily.

When do police use their sirens?

Sirens are used in a variety of situations. Primarily, they are used so that the police operators can get to where they need to go as quickly as possible and without any accidents. When pedestrians hear the sirens, they avoid going on the roads, and other drivers will make way for the vehicle as quickly as possible. As mentioned, the sirens also play a role in helping the police fulfill their duty, and are often used to signal other drivers to pull over during a traffic stop. In most cases, the sirens are only used if the other driver is causing a clear and present danger, such as speeding. Otherwise, the emergency vehicle lights alone might be used.

They’re also used to alert people that the police car is on its way. It can work as a deterrent against an ongoing crime and let a victim know that help is at hand. Similarly, if emergency response workers are dealing with a situation on the road, it can also let them that they will soon receive help.

Police sirens are used in a variety of situations, including escorting over vehicles, clearing the road for other vehicles, as well as all of the purposes above. As mentioned, the police will change their sirens depending on the environment, the situation, and even on the presence of other emergency vehicles.

Extreme Tactical Dynamics has a range of police siren controls on the store, many of them featuring the three most common sirens, as well as some additional functions. Hopefully, this guide has helped you understand a little more about when each siren is used and why there are multiple different kinds in the first place. The differences might sound almost trivial, but they are greatly important for police on the road.

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