Creative warning system!

[JasonC]

Hence, this is why a 100w police siren can be heard from a mile away easily while a 100w subwoofer is considered a very paltry room/car sub. I forget the exact scientific explanation, but if I feel like looking it up I'll post it here.

I seriously doubt that any 100w police siren could be heard a mile away. Even most electronic outdoor sirens can't be heard that far away.

You can often hear distant electronic sirens that far away. I have many times. Of course you need to be in the country and not in the city for this.

[Whelen Rules]

Hence, this is why a 100w police siren can be heard from a mile away easily while a 100w subwoofer is considered a very paltry room/car sub. I forget the exact scientific explanation, but if I feel like looking it up I'll post it here.

I seriously doubt that any 100w police siren could be heard a mile away. Even most electronic outdoor sirens can't be heard that far away.

You can easily hear 100 watt EV sirens over a half mile away in some cases. Some outdoor warning electronic sirens (Whelens WPS and Vortex series in particular) can be heard for over 2 miles

[StonedChipmunk]

But this is in completely flat barren wasteland. City environments, or low-density urban environments, would not support something like that.

[Thunderbolt 612]

Another creative siren would be an electronic siren with a screw based driver, so if the speaker driver fails, it can be replaced like a light bulb.

[Justin]

... 6000 dB...

Wikipedia entry on Sound pressure

201 dBSPL is supposed to be enough to kill someone.

[Robert Gift]

... higher pitched sounds do travel further. (Sentry Siren uses this principal in their dual tone sirens) For example, a 1,000Hz sound wave at 100 watts of power will travel much further than a 100Hz sound wave also at 100 watts of power. ...

from Whelen Engineering FAQ section:
"Whelen siren systems are designed to optimize the production and projection of low frequency warning tones. It is documented that higher frequency tones attenuate (lose power) more over distance than low frequency tones.

A warning siren capable of producing 124 dB at 100 feet with a 500hz warning tone will be more effective than a siren producing 124 dB at 100 feet using a 1,000hz warning tone. This factor should be considered in planning a warning system.

Consider this example of the attenuation of higher frequency tones that is apparent in our everyday life..................

As you are standing out in your yard, your neighbor's teenage son has the stereo in his car blasting as he is coming down the road toward your house. The earth seems to shake as the "boom, boom, boom" of the low frequency bass notes are felt beneath your feet and on your ears. It is not until the car is very near to you that you can hear the high frequency acoustic guitar and voices. As the car
passes you, these high frequency tones seem to disappear, but the pounding and
thumping of the "boom, boom, boom" bass can still be heard and felt.

This scenario clearly demonstrates that ability of the lower frequency tones to be heard at a farther distance than the higher frequency tones.

In short, remember that not all 124 dB (at 100 feet) sirens are alike."

[Robert Gift]

Another creative siren would be an electronic siren with a screw based driver, so if the speaker driver fails, it can be replaced like a light bulb.

That would be a convenient innovation.
It would also eliminate the possibility of someone reversing polarity of wires when replacing a bad driver.
But could vibration cause a driver to unscrew enough to become a poor contact? Screw lug connections could have lockwashers to ensure tight contact.

[SirenMadness]

Having a lower-pitch speaker-based siren does have its disadvantages: its driver(s) have a greater chance of blowing than drivers of a higher pitch, so the choice is really harder than it seems. A high pitch does not have a greater range of travel than a lower pitch, but it does have a greater range of efficient audibility, which is the reason for Sentry integrating weird combinations of rotors on their sirens.

Also, Whelen's EZ-Pull system of drivers is easier to get out and back into the siren than a screw-type-driver system, as a system such as that would take more complexity in manufacturing; you will have to design a winding that goes around the driver's magnet, and you will have to put a winding into the housing of the siren, though your idea sounds cool.

[SoundOff]

In scooterbugs25's Toroidal Whistle thread on the "Other Warning Systems" section; I looked up the specs on that and the later version produced 165db measured about 3 feet from the horn. The same unit was measured 135db at 100 feet on axis.

One of the sirens I drew up was somewhat of a cross between an Alertor and a RM-130. The Alertor part was actually a squirrel cage type blower that fed air into a chopper with each port opening into the RM-130 style horn. I don't know how it will perform exactly though.

The omnidisc series sirens I drew had the cells shaped like an SD-10 [>-<] with 2 drivers fireing up and down towards the center and out. One thing I did see with my design would be the entire stack would have to be disassembled if you needed to change the drivers.