Allertor Question.

[Allertor113]

Okay,Im a big fan of the Aca Allertor... And i have one question.
Was the top Intake/Outtake to increase Db Levels,OR to increase air flow to the Rotor/Stator Due to the fact they don't have Blowers to Increase Db Levels.
Thanks in Advance for the Info,

-113

[500 AT fan]

Top extension was supposed to be a horn. Bottom section was the intake. Seems to work best on earlier versions of the siren with the smaller horn.

[Allertor113]

Hmm.... well thats not the best idea in my "eyes." Where there any say...
"Sound Deflectors" that would "Re-Direct" the air and sound to the horn.

[500 AT fan]

That's partly why it was discontinued in the 80's, in favour of the P-10/15. It wasn't the best thought out design.

It was an interesting idea, though.

[SirenMadness]

There was probably some cancellation going on in the drum, so it wasn't a very good design, though it was pretty cool. Also, yes, the bell-shaped intake was to aid in intake of air, kinda like the front "bell" of a turbo.

[kx250rider]

There's some heavy math involved in accoustical engineering, and it's all way above my head. I do have friends who are educated in that, and they go on for hours explaining the properties of horns. The smallest mistake could cause the horn to resonate wrong, and cancel it's effect or even reduce the sound level. In a nut shell, as it was explained to me, the waves have to be able to hit one side of the horn, and bounce off to hit the opposite side, and at exactly the right time and space from the beginning of the horn to the end. An analogy would be when you drive a car on a concrete road, paved in sections with seams crossing the road each (so-many) feet, you can feel a strong, increasing rhythm at a certain speed, and again at a multiple of that speed, etc. But if you drive a car with a slightly longer or shorted distance between the front and back wheels, the speeds and the tone of the rhythm will be all different. And if the wheels are a certain distance front to rear, it can completely cancel the rhythm and be smooth.

Charles

[SIRENMAN]

Jim Biersach is probably the undisputed expert in siren design. His designs have been copied by Federal time after time. So I am confident that the allertor was designed to the Max.

[Adam Pollak]

Also remember that if you were a civil defense director for a city, you would be presented with the 2 main air raid sirens from Federal and ASC- the Thunderbolt and the Allertor.

*Both dual-tone version have a 125 dB rating (at some point, though there were fluctuations).
*The Thunderbolt has 3 motors and more control boxes and parts. An Allertor just needs a single telephone-activated relay from a central timer.
*The Allertor was cheaper than a T-Bolt.
*The Allertor was a single device to install on a pole with a bracket. T-Bolts needed air pipe and blower mounting.
*Though they both have minor preventive maintenance issues, a T-Bolt requires more time and thought into it up front per the manual.

The Allertor definitely was a competitive siren, but of course never had close to the market share.

[snelson17]

Who cares. It just sounds great.