Just wondering why ambulance is louder than unmarked police on this video

[Dr Ferran]

I just find this video:

and I'm wondering why the second car (ambulance) is louder than unmarked police car? Because of speaker or what? My suspicion is that the ambulance have Model Project A-Flex Speaker and police car have a SA315P speaker. Is it possible?


And from other hand what speaker is better, louder, deeper etc.? Projector A-Flex or SA315P?


Thanks for any answers

 

[C17LVFD]

My first guess would be the ambulance has 2 100 watt speakers. But I couldn't actually see speakers on that ambo so it's unknown.


I've found a low-profile speaker doesn't have the same output as a larger speaker like a AS124 or TS100 which can change the sound of the sirens.


Also some sirens despite being rated at 200 watts just don't seem to be as powerful as others rated at 200 watts. Take a PA300 vs an Omega 90. The Omega 90 will in my humble opinion blow the PA300 out of the water.


Hope that helps.


Seth

 

[charlie82]

The mounting in the unmarked unit could be at an odd angle or obstructed. Often times this is done when space is limited.

 

[Fast LT1]

Well around here most Police cars are 100w and ambulances 200 watt and firetrucks are usually 200 but some go up to 400 watts.

 

[RL1]

Wail vs yelp may have something to do with it too.

 

[Rofocowboy84]

Take a PA300 vs an Omega 90. The Omega 90 will in my humble opinion blow the PA300 out of the water.

Aren't most PA300's only 100W?

 

[Newberry13]

Aren't most PA300's only 100W?

Yes, but they are available in 200 watt as well. Except for the PA-300-R which is only available as a 200 watt unit.

 

[Dr Ferran]

Both vehicles have Whelen Alpha Remote or Whelen Beta Remote siren, so both are 100W.


http://www.woodwayengineering.co.uk/index4a.html from British distributor of Whelen products


And my question: which one is louder - SA315P or A-Flex Projector?

 

[SireLite]

The reason the siren on the ambulance is louder is because the siren speaker is mounted so the front of it sticks out of the front bumper. Instead of it being mounted where the sound would be obstructed.

 

[Dr Ferran]

But you show old stylish ambulance. New Mercedes Sprinter looks like this:


http://ambulance-photos.com.s3.amazonaws.com/2368.jpg


You cannot see speaker in front of the vehicle.


http://ambulance-photos.com.s3.amazonaws.com/1299.jpg

 

[tnems7]

Regarding the Project-A-Flex question. IMHO I doubt that this will be louder than the bumper mounted SA315 or the 314 models. And, for maximum acoustical effect, you need to keep the flexible acoustic tubing at 60 inches and cut it in four inch intervals. I purchased the speaker off Ebay that only had a foot of acoustical tubing, and it seemed to have lost the benefit of the whole project-a-flex design. The tubing was significantly degraded due to heat and exposure. (Replacement acoustical tubing from Whelen was around $175, so I substituted a good quality radiator/heater hose and just use this speaker to check out sirens.)


Usually, shorter tubing would acoustically lose lower frequency bass tones and enhance higher treble tones. Whelen warns that with some siren tones, the sound may be distorted by the Project-A-Flex design. I do wonder that with some types of air horn sound, if a different "trumpet" speaker cone might enhance the air horn effect?


I would recommend more recent production speakers from Whelen, Carson, and other manufacturers instead of the Project-A-Flex.

 

[SireLite]

Here's a photo of the ambulance that was in the youtube video.


http://www.flickr.com/photos/jon-999/3827907060/


Looks as if it might have the new woodway projector flex mounted in the lower grille. http://www.woodway-online.co.uk/acatalog/Sirens_Speakers.pdf see page 2. The one that looks like a hoover accessory.

 

[911]

also, its a video..........you are not going to get true audio distinction from it

 

[chris_m]

Also the car is not police its a St John Ambulance Vehicle, I believe its only got a 30w speaker (could be wrong) as for the truck its a different one to the one my local trust uses (the speakers in ours are in the bumper) when i am next in London/near a LAS station I will look in to this for you...


Will try get some more info on the car also...

 

[Henry455]

For anybody interested, this is an article from the late 80's, before the popularity of compact speakers, discussing speaker housing design/size versus sound output.


Loudspeaker Directivity and Vehicle Siren Sound Levels


And are some current speakers more efficient (louder) than others, YES.

 

[bobnash78]

Almost all ambulances worldwide have two 100 watt speakers and I'ver never seen a police car with more than one speaker.