Sirens 101: Why so many different types?

Have you ever wondered why there are so many different siren designs in the US and Canada? Well, this video aims to introduce many of the different siren manufacturers and their siren lineups, and why these different designs exist.

ACA to ASC ~1992-1993 transition period: https://www.airraidsirens.net/forums/...

Timestamps:
0:00 | Copyright/Fair Use Disclaimer
0:03 | Intro
0:08 | More disclaimers/notices
0:14 | Part 1: How sirens work
3:02 | Part 2: Sound dispersal designs
3:46 | Part 3: Current sirens and siren manufacturers
(in North America)
4:03 | American Signal Corporation (ASC)
5:03 | Acoustic Technology, Inc. (ATI Systems)
5:35 | Federal Signal Corporation (FS)
7:17 | Sentry Siren, Inc. (Sentry)
10:18 | Whelen Engineering Company (Whelen)
12:14 | Part 4: Defunct siren manufacturers (from North America)
12:31 | Alerting Communicators of America (ACA)
15:23 | Biersach & Niedermyer Co. (B&N / BNCO)
16:09 | Canadian Line Materials, LTD. (CLM)
17:38 | More examples (of defunct siren manufacturers)
17:56 | Part 5: A siren so special it deserves its own section
18:31 | CREDITS
19:14 | End of video

CREDITS
Producer, editor, and writer:
Siren Archives (me)

Siren information:
Civil Defense Sirens Wiki, Siren Archives (me), manufacturers [credited throughout]

Siren pictures:
Various online sources, Siren Archives (me) [credited throughout]

Siren sounds:
Manufacturers, Siren Archives (me), various online
sources

Shoutout to:
   / @warningsirensofmichiana  
   / @trainsandsirens1  
   / @mnsirens  
   / @4j25  
   / @americansirenproductions  
   / @goomanhlr5697  
   / @thesirengeek  
   / @northernindianaoutdoorwarn9698  
   / @steelcitysirensandtrains  
   / @dixielandfarms8628  
   / @ohiooutdoorwarningsirens  
   / @centralohsirens  
   / @bluegrasssirens1938  
   / @cameramanjohnny  

Example videos:
Siren Archives (me)

Background music:
Sundown, Bedrock - Nokia
Alpha Centauri B - Anders Enger Jensen

Credits music:
Floaters - Jimmy Fontanez/Media Right Productions