100 or 200 watt siren for highway usage?

Fast LT1

Fast LT1

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May 24, 2010
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Sedgwick County, KS
Any ideas on the best siren to use on a highway going about 80mph. I'm not sure if 100 watt would suffice i figured i'd probably be "outrunning" the sound almost. Would it be wise to go to a 200 watt siren? I'm not much in the siren department.


If you recommended a specific model it Must have Air horn, wail, yelp, and hyper yelp/piercer.
 
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That fast, it's not going to matter. You're outdriving the sound.
 
This comes up over and over again. The speed of sound in air at sea level at 20 degrees C (about 68 degrees F) is 343 m/s or about 767 MPH. If the siren sound is coming towards you at 767 MPH and you're going 80 MPH in the same direction, you can see how "outdriving" the siren is not going to happen.


What happens is that the engine noise, airflow noise, tire noise etc go up the faster you drive, and make it more difficult to hear things around you including sirens, when the sound pressure of the siren sound is the same as or lower than the sound pressure of noise inside the car. Also, sound pressure varies with distance so a siren half a mile back is not going to be very loud in any case. But you're not "outdriving" it.


Since most of this interior vehicle noise is toward the higher frequency range, using something like a Rumbler might help. Also, using something like a Q or Grover horns which are relatively louder might help. But a 200 watt siren is only a moderate improvement over 100 watts. If you double the acoustic power in watts, you get only a 3 dB or 1.41x (41%) increase in sound pressure and 1.23x (23%) increase in perceived loudness.


So, a 200 watt siren will seem about 23% louder than a 100 watt siren, at the same distance. But you're not going to outrun or outdrive the sound unless you're in a jet. Then it's called breaking the sound barrier.


http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm
 
Klein said:
200 watts...always. I run 400w (200w ss2000 and 200w Omega 90).
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:eek: Thats a lot of sound coming from an Explorer.


When are we going to take it to 600W Charlie?:twisted:


Random side note, did you get that Pinnacle in your Explorer yet? I'm excited for an update:)
 
aberfitchguy2472 said:
:eek: Thats a lot of sound coming from an Explorer.

When are we going to take it to 600W Charlie?:twisted:


Random side note, did you get that Pinnacle in your Explorer yet? I'm excited for an update:)
Click to expand...


400 is plenty. I typically have one on wail and other on yelp. Or just have the Omega 90 going since I prefer that siren's tones over the SS. I think I am actually gonna use one of my speakers on an upcoming install....maybe. Luckily I havent had any cancellation from the speakers. I would like to just find a way to hear my truck coming from like a mile away but that is difficult to do so I can "see" if there is any reduction in loudness.


I DID get the Pinnacle. Apologies, I did not update. Been busy trying to reconfigure some things but I can shoot a vid today since it is all purty outside and Eduardo is clean.
 
It has been my experience that no amount of siren really gets noticed from more than about 20 feet on an interstate. I know when emergency vehicles pass me on the expressway I hear them as they go by.
 
JohnMarcson said:
It has been my experience that no amount of siren really gets noticed from more than about 20 feet on an interstate. I know when emergency vehicles pass me on the expressway I hear them as they go by.
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True that. The only reason I even used a siren on the highway at all was to keep it legal. Lights are what do the job.
 
JohnMarcson said:
It has been my experience that no amount of siren really gets noticed from more than about 20 feet on an interstate. I know when emergency vehicles pass me on the expressway I hear them as they go by.
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+1


Although I do agree with the grover comment, and I also hear (real) mechanical sirens better than electronic @ highway speeds..


Overall, don't rely on anything audible to get a drivers attention until you are less than 10 feet off his rear bumper @ highway speeds. Well, unless you have one of the following devices below... ;)

 
unlisted said:
+1

Although I do agree with the grover comment, and I also hear (real) mechanical sirens better than electronic @ highway speeds..


Overall, don't rely on anything audible to get a drivers attention until you are less than 10 feet off his rear bumper @ highway speeds. Well, unless you have one of the following devices below... ;)

Click to expand...

Yea i couldn't even begin to imagine an impala ss with that mounted on it!
 
Wow!


If anyone's had the unfortunate experience of having a vehicle panic stop in front of you when you hit the siren, imagine what one of those would do! :eek:
 
NPS Ranger said:
Wow!
If anyone's had the unfortunate experience of having a vehicle panic stop in front of you when you hit the siren, imagine what one of those would do! :eek:
Click to expand...

Probably push the car thats in front of you about 10 feet!
 
Check out "www.timberwolfsirens.com." The "Timber Wolf Siren," a compact mechanical siren that uses minimal amps on startup and, accordingly, is more suitable for mounting in the grille of a Crown Vic than a larger vintage "iron horse." The Timber Wolf outperforms electronic sirens, particulary at highway speeds.
 
I only use 200watt in my vehicles. I dont use my siren on the Highway a lot. If you have enough lights you dont really need a siren unless its bumper to bumper traffic.
 
I have used 400w plus airhorn w/o any success.... people just don't hear sirens on the expressway at > 60mph... you could do 400w, Q and airhorn with no effect. Besides I find running hot on the interstae is actually more dangerous and slower then shutting down and going with the 70mph flow of traffic in many cases. People do awful stuff on highways when you come up behind them code3.
 
I drive an ambulance at work and do inter-hospital stuff (cardiac and trauma retrievals, generally) so I'm on the highway most of the time I'm behind the wheel. Sirens are useless at cruising speeds if you're trying to get the attention of another driver in front of you. With the late model luxury cars they won't even hear you side by side. I only use my sirens in slower traffic, toll plazas, on/off ramps on surface streets. Wig-wags seem to work the best for warning, on a straight stretch of highway I was running the normal ambulance lights (box lights plus lightbar and grill lights) for about a mile behind a few cars and about 100 yards out my lane was still blocked. Flicked on the wig-wags and a couple seconds later, brake lights flashed and they moved over. YMMV. :)
 
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