Audible Alarm Tones
When you think of the term ‘car alarm’, the first thing that comes to mind is exactly that – an alarm! A (usually) very loud audible signal of some sort that alerts those around to an issue that requires urgent attention.
There are different types of alarms that work in different ways, but in terms of vehicle alarms in particular, audible tone is usually achieved through an external siren that’s integrated with the main unit of the vehicle security system.
It is a common misconception that the only purpose of an alarm is to attract attention and / or ward-off potential intruders. It is a well-known fact that intruders are not intimidated by sirens blaring and silencing them is no challenge to any potential thief.
Most car alarms are installed in a generic way, and don’t serve much of a purpose, except annoying the neighbours 😋 However, if used clevery, a siren can play an instrumental part in theft prevention.
A number of surveys, as well as practical tests, had been conducted in relation to people’s reaction to car alarms, and the conclusing is clear: most people (about 99%) will completely ignore the situation if a starnger’s car alarm is triggered in a public place in their presence — even if the onlooker sees that the vehicle is being tampered with by someone who clearly is not its owner.
Another important thing to remember, is that a siren (be it a regular siren or the autonomous variety) can be disconnected and silenced in seconds.
Popular Siren Tones
Standard
Single tone medium pitch sirens are, perhaps, the type most widely used for aftermarket vehicle alarm systems. They come in a variety of tones and are usually easily tolerated.
Multi-Tone
Multi-tone sirens are quite popular. A single alarm cycle generates multiple tones (usually 6), but the pitch is the same. These are medium-pitch sirens whose sound is easily tolerated.
Hi Pitch
High-pitch sirens produce an ear-piercing sound that most people have a low tolerance for. These are effective when used internally (in the vehicle’s cab) to deafen the intruder.
Low Pitch
Low freqency sirens are rarely used on their own. They normally accompany the main siren or are used in combination with several sirens for a sound wave to create acoustic discomfort for a would-be thief.
Piezo
Piezo sirens are usually compact in size, and somewhat similar to high-pitch sirens.
MP3
MP3 sirens are designed for those, who want an individual siren sound. An MP3 file with any sound of your choice can be uploaded onto the siren. Screams for help are the most popular option.
Horn Honk
When an alarm system is connected to the vehicle’s own horn, it generates a horn honking sound. This can be used on its own or combined with an external aftermarket siren(s).
Special Tone
Imitation of publically recognisable sounds, such as police and emergency vehicle sounds, as well as civil defense and national emergency alarm sounds, ex. nuclear / natural disaster / etc. warning.
Most of these are illegal to use on personal vehicles.
Siren Types
Other than regular sirens, there are also other varieties, the most commonly used for vehicle security systems are the following:
Autonomous (Back-Up) Sirens
It is a common misconception that back-up sirens offer more benefits compared to regular sirens, as they “cannot be silenced” by cutting the cable or disconnecting the vehicle’s battery. Back-up sirens have a built-in battery that ensures the siren continues to trigger even when disconnected from the main power source. However, these sirens fall apart easily when dropped, and can also be silenced by spraying them with a certain substance. One major drawback of back-up sirens is that they tend to drain the vehicle’s battery within a year of installation. In conclusing: this type of siren does not offer any significant benefits compared to regular sirens, and in fact is more prone to issues.
Bluetooth / Wireless Sirens
Some manufactures offer wireless, as well as plug-and-play, sirens that communicate with the main unit of the vehicle security system over-the-air, usually using a common protocol, like BluetoothSmart. The only real benefit this type of siren offers is that the siren is not physically connected to the main unit and therefore leaves a spare slot that can be used to upgrade the system with another external component (such as an additional sensor). There are several major drawbacks to these types of sirens. The siren communicates with the main unit of the vehicle security system using a frequency (instead of physical connection), and hence – a frequency jammer can be used to jam communication. These sirens can also lose connection with the main unit in certain environments (where radio-interferences are more common), which will either render the siren dormant or generate a false alarm. Another major drawback is that these sirens are manufacturer-specific i.e. they will only work with products of their own brand, and hence – are not as easily replacable as the universal variety.
Customisation
StarLine systems are very customisable, and that includes audible confirmation tones, warning tones, and main alarm tones. A siren can be manipulated to create an individual tone, so that the owner can recognise it amongst other – identical sounding – alarms.
Making the Most of a Siren
The most commonly seen type of audible alarm accompanying a vehicle security system is a single external siren, usually installed in the engine compartment. This is the least effective way to utilise a siren (whatever the type), and doesn’t present much of a challenge to a potential thief.
Here are some tips as to how to make the best of an alarm siren:
Restricting access to the siren:
Using a bonnet lock to prevent access to a siren installed in the engine compartment will significantly increase the chances that a would-be thief will abandon the vehicle as they’ll be unable to silence the siren.
Horn honk:
Connecting the vehicle security system to the car’s original horn will create a super-loud alarm that’s hard to ignore, and takes longer to silence.
Using multiple sirens:
Installing several sirens of different frequencies in the vehicle’s cabin will create ‘acoustic discomfort’ for the thief, disrupting concentration, and making it near-impossible to be inside the vehicle for any period of time.