Whelen Direct Replacement

[acoustics101]

http://www.whelen.com/_MASSNOTIFICATION/4000.php

http://tinyurl.com/3bagehn

Very interesting that Whelen suggests a WPS 4004 as a replacement for a T-135. The WPS 4004 has a 70 dB radius of 6000 feet, whereas the T-135 has a 70 dB radius of 2 miles! By doing the math (A = pi x r squared) you would need over three of the 4004s to get the same degree of coverage as a single T-135! It must have something to do with the new math. The only possible advantage I can see is voice capability.

[acoustics101]

http://tinyurl.com/3ozjrcn
Compare the 70 dB radii of the sirens below to what I was able to achieve at my toroidal whistle tests held in July, 1982 at the Cincinnati/Northern KY International Airport.

http://www.whelen.com/_MASSNOTIFICATION/4000.php

http://tinyurl.com/3bagehn

Very interesting that Whelen suggests a WPS 4004 as a replacement for a T-135. The WPS 4004 has a 70 dB radius of 6000 feet, whereas the T-135 has a 70 dB radius of 2 miles! By doing the math (A = pi x r squared) you would need over three of the 4004s to get the same degree of coverage as a single T-135! It must have something to do with the new math. The only possible advantage I can see is voice capability.

[Jim Z]

It must have something to do with the new math.

no, it has everything to do with "never take purchasing advice from the guy trying to sell you something."

[sirenita]

I wish sirens would stop trying to cross breed

sirens need love, too.

[sirenita]

all about your friend, the hornet:

http://www.whelen.com/pb/Mass%20Notific ... Hornet.pdf

[acoustics101]

I agree. I was just being facetious about the new math. It helps when you know the actual math involved.

Doubling the radius always results in four times the area. Taking a radius of 2 miles (10,560 feet) vs 6000 feet, which is not quite double, the ratio in the increase in radius is 1.76:1. Squaring that gives us an increase in area of approximately 3:1:1. There is no getting around the actual math.

It must have something to do with the new math.

no, it has everything to do with "never take purchasing advice from the guy trying to sell you something."

[Jim Z]

I agree. I was just being facetious about the new math. It helps when you know the actual math involved.

I'm an acoustics engineer. I'm well aware, thank you.

[Hacksaw]

Cyclone-can be replaced with a 2909
STL-10- can be replaced with an OA2, or a 2901

A 2909 has about 129db @ 100 feet, so that would work for a Cyclone, 125db @ 100 feet.

But, I think you would need about a 2903 to equal an STL-10. The stock pitch difference will hurt coverage there.

[sirenita]

why stop at a 2903? go all the way. get a 2910.

[carexpertandy]

Cyclone-can be replaced with a 2909
STL-10- can be replaced with an OA2, or a 2901

A 2909 has about 129db @ 100 feet, so that would work for a Cyclone, 125db @ 100 feet.

But, I think you would need about a 2903 to equal an STL-10. The stock pitch difference will hurt coverage there.

According to Whelen's website, the 2909 is 128 dB at 100', and the 2906 is 125 dB at 100', so you don't really need a 2909 to replace a Cyclone.

Also, the 2903 is 119 dB at 100', and the 2902 is 115 dB at 100', so you don't really need a 2903 to replace a STL-10.