question: Why do emergency sirens sound different in the US versus in Europe?
comment: There's no single standard for emergency sirens on vehicles, and different companies make different siren technologies, and different police forces buy from different siren companies.
passages: Section::::Civil defense sirens around the world.:Europe.:Finland.
  
  A general alarm consists of a repeating 1-minute sound that consists of tones ascending for 7 seconds and descending for 7 seconds. The end of danger is signaled by a 1-minute continuous tone. Warning sirens are tested on the first Monday of every month at noon. The testing alarm is shorter than the general alarm (only lasting for 7 or 14 seconds) and may be a flat tone.
  
  Section::::Civil defense sirens around the world.:Europe.:France.
   Section::::Civil defense sirens around the world.:Europe.:Germany.
   Section::::Usage in other countries.
  
  in 2009, Hörmann Sirens and Sircom AG of Germany has thought of using the SCDF's Public Warning System's siren as a base to make their own sirens, made two types of sirens based on Singapore's PWS designs: the ECN 1200, which is based on SCDF's 'Standard' build but with an unusual arrangement of its eight acoustic radiators and the ground type ECN 2400 also with its unusual arrangement of its radiators and Sircom's version with its sixteen radiators attached to front and rear of the pole.
  
  Section::::See also.
  
  BULLET::::- Cell Broadcast
  
  BULLET::::- Emergency population warning
   Belgium used to test its air raid sirens every first Thursday of the trimester. Sirens are Sonnenburg Electronic sirens. When the air-raid sirens are tested, the message "proefsignaal" or "signal d'essai" is pronounced every time the sirens work. There are 540 sirens placed all across the country. The system's use was discontinued in January 2019.
  
  Section::::Civil defense sirens around the world.:Europe.:Czech Republic.
   Section::::Civil defense sirens around the world.:Europe.:Slovenia.
  
  Slovenia has 1,496 operable civil defence sirens. Most of them are electronic sirens, although there are some mechanical ones. Civil defence sirens are mounted on fire stations, town halls, etc.
  
  Three siren tones are used in the whole country:
  
  BULLET::::- Warning: 2 minutes long steady tone. Used to warn of the impending danger of a fire, environmental or other disaster, or high water level.
  
  BULLET::::- Immediate danger: 1 minute wailing tone. Used to warn of the danger of a major fire, flood, radiological and chemical danger, or air raid.
   In Germany, the ""Warnämter"" (warning authorities) were closed in the 1990s after the Cold War threat no longer existed, and the ability to alert the public was considered unnecessary. As the civil defense sirens were also frequently used to alert volunteer firefighters, many sirens were sold to municipalities for a symbolic price; others were dismantled. In the 2000s, it was realized that the ability to warn the public is not only necessary in cases of war, but also in events like natural disasters, chemical or nuclear accidents, or terrorist attacks. As a result, some cities like Düsseldorf and Dresden began to rebuild their warning sirens. In Hamburg, the sirens are still operational. They warn the public during storm surges. The majority of operational sirens in Germany are either electric-mechanical type E57 or electronic sirens.
   BULLET::::- Israel has 3100 sirens as a part of its warning system, and 300 of them are HPSS32 sirens.
  
  BULLET::::- Sedgwick County, Kansas and the City of Wichita 27 ATI HPSS32 units are part of the system's 150 sirens.
  
  BULLET::::- Forsyth County, Georgia
  
  BULLET::::- Frisco, Texas ATI HPSS32 units.
  
  BULLET::::- Fort Riley, Kansas 2 ATI HPSS16 units.
  
  BULLET::::- Del City, Oklahoma 8 ATI HPSS16 units.
  
  BULLET::::- Malmstrom AFB, MT 6 ATI HPSS16 units
  
  BULLET::::- Pasig City, Philippines has 1 ATI HPSS32 unit.
   Singapore currently has a network of over 2,000 stationary sirens named the Public Warning System which warns the entire country of air raids, and human-made and natural disasters (except earth tremors). On the first day of every month, Singapore's sirens are tested. During the test, the sirens sound a light cheerful chime instead of any of its three signals. The sirens look very similar to the ECN3000 Israel version.
  
  Section::::Civil defense sirens around the world.:Asia.:South Korea.
   The mechanical siren was used on police vehicles, ambulances, fire apparatus and other emergency vehicles beginning in the early 1900s. The first were driven with a hand crank or driven by the vehicles tire or fan belt. They were manufactured by the Sterling Siren and Fire Alarm Company in Rochester, NY; B&M in Los Angeles and a few others. Later, electric motor driven sirens were widely manufactured by Federal Signal Corp, Sireno, Sterling and a few others. Beginning in the late 60's, the electronic siren began to replace the mechanical siren. It provided several tones (wail and yelp) and a PA option. The electronic siren did not clog with snow in the winter (NYPD cops would beat the roof mounted siren with their nightsticks to break off the ice.) Federal Signal emerged as the largest manufacturer and makes (in University Park, IL) the "Q" siren to date. B&M still makes their "Super Chief" to date in their California facility. One other US manufacturer makes a "Timberwolf" siren.
   Section::::Early production siren models.
  
  Original siren from early production (1940's-1950's):
  
  BULLET::::- Mobil Directo (Biersach & Niedermeyer brand)
  
  Sirens from the 1960s until the 1980s:
  
  BULLET::::- ACA Allertor 125
  
  BULLET::::- ACA Hurricane 130
  
  BULLET::::- ACA Hurricane 130 MKII
  
  BULLET::::- ACA Screamer Series. (Ranging from 2 HP to 10 HP)
  
  BULLET::::- ACA Banshee 110
  
  BULLET::::- ACA Banshee 115
  
  BULLET::::- ACA Sentry 95
  
  BULLET::::- ACA Cyclone 125
  
  BULLET::::- ACA Cyclone 120
  
  Sirens in production during the 1980s until the early 1990s:
  
  BULLET::::- ACA P-10
  
  BULLET::::- ACA P-15
  
  BULLET::::- ACA P-20
  
  BULLET::::- ACA P-50
  
  BULLET::::- ACA Howler
  
  BULLET::::- ACA Alertronic 6000
   Smaller-scale sirens are also deployed, like the Model 5 or Model A, used at fire stations for call-outs and at Sydney's beaches for shark alarms. Alarms are also used around prisons for breakouts and at many factories and schools to announce start and finish times.
   In United States English language usage, vehicular pneumatic sirens are sometimes referred to as mechanical or coaster sirens, to differentiate them from electronic devices. Mechanical sirens driven by an electric motor are often called "electromechanical". One example is the Q2B siren sold by Federal Signal Corporation. Because of its high current draw (280 amps when power is applied) its application is normally limited to fire apparatus, though it has seen increasing use on type IV ambulances and rescue-squad vehicles. Its distinct tone of urgency, high sound pressure level (123 dB at 10 feet) and square sound waves account for its effectiveness.
   BULLET::::- Sirens - These can be fully electronic, electric, or manual, but are all designed to create changing sound patterns. These patterns vary by model of siren. Emergency drivers are often trained to use different siren tones in different conditions, to achieve maximum effectiveness through traffic. A long-standing problem for emergency services has been traffic being unable to determine the direction a siren is approaching from, and different tones have been developed on some electronic sirens to help combat this, such as the use of white or pink noise in between more conventional siren noises, which helps people to pinpoint their origin.
   Norway has about 1,250 operational sirens (mostly Kockums air horn units rather than motorized sirens), primarily located in cities. Three different signals are used.
   Sirens began to replace bells for municipal warning in the early 1900s, but became commonplace following America's entry into World War II. Most siren models of this time were single-tone models which often sounded almost an octave higher in pitch than their European counterparts. Dual-tone sirens became more common in the 1950s, but have been used in some areas since about 1915. During the Cold War, standard signals were used throughout the country for civil defense purposes, referred to as "alert" and "attack." Volunteer fire departments generally used a different siren signal. Many towns, especially in California and New England, used coded air horns or diaphones for fire calls and reserved sirens for civil defense use.
   BULLET::::- Auckland Radio Ltd – A Waihi, New Zealand company that built warning sirens based on a local design used in fire engines. The Akrad air raid siren was built from 1939, until the factory was closed in 1984. Many fire stations in New Zealand have the sirens, for both fire and civil defense purposes.
   Tire driven sirens were made by Harley Davidson but became obsolete in 1982 when California required a police motorcycle to be able to emit a siren sound while stopped. New York City's noise regulations made mechanical sirens obsolete there in the early 1970s; they were too loud and the sound was too widely projected. The NYPD then used a 58 watt electronic siren with a small roof mounted speaker. The old roof mounted Federal P660 "Pulsator" sirens were history.
  
  Section::::Present day.
   Section::::Sirens in integrated public warning systems.
  
  Sirens are sometimes integrated into a warning system that links sirens with other warning media, such as the radio and TV Emergency Alert System, NOAA Weather Radio, telephone alerting systems, Reverse 911, Cable Override, and wireless alerting systems in the United States and the National Public Alerting System, Alert Ready, in Canada. This fluid approach enhances the credibility of warnings and reduces the risk of assumed false alarms by corroborating warning messages through multiple media. The Common Alerting Protocol is a technical standard for this sort of multi-system integration.
   BULLET::::- University of West Florida In Pensacola, Florida, ATI HPSS16 sirens here are used for chemical spills, weather warnings, lock downs, and they play a daily Westminster chime tone at noon.
  
  BULLET::::- Arnold, Missouri 7 ATI HPSS32 units which replace the old Whelen WPS 3016 Sirens.
  
  BULLET::::- Ketchikan, Alaska maintains a system of 3 ATI HPSS32 units which are tested audibly on the 15th of the month at noon. These sirens are used to warn for tsunamis or in the event of a dam failure.
  
  Section::::Problems and criticism.
   Warning sounds vary from area to area, including rising and falling notes and Morse code sirens. Communities with volunteer fire brigades use a continuous note on all sirens for civil defense, and a warbling siren on the fire station siren only for fire callouts. Civil defense uses a distinctive "sting" siren that is used by all radio stations nationwide, but is currently only used for civil defense sirens in Wanganui.
  
  Section::::Defunct manufacturers.
   Today, signals are determined by state and local authorities and can vary from one region to another. The most common tones produced by sirens in the United States are "alert" (Steady) and "attack" (wail). Other tones include Westminster Chimes (commonly used for the testing of electronic sirens), Hi-Lo, Whoop, Pulse, Air Horn, and fast wail.
   BULLET::::- Toshiba – The company is still in business, but no longer manufactures its unusual omnidirectional, compressor-charged siren.
  
  BULLET::::- Decot – A Wisconsin-based manufacturer of fire sirens as early as the 1910s. They also produced CD sirens in their later days. Defunct since the 1950s, they invented one of the first dual-tone sirens around the 1910s.
  
  BULLET::::- Erick – A Minnesota-based manufacturer, started in the 1920s and liquidated around the 1950s. Although the sirens were intended for fire-department use, they were also suitable for warning of air raids and nuclear attacks. These types can be found in the Midwest.
   Some Heavy Metal bands also use air raid type siren intros at the beginning of their shows.
  
  Section::::Vehicle-mounted.
  
  Section::::Vehicle-mounted.:Approvals or certifications.
  
  Governments may have standards for vehicle-mounted sirens. For example, in California, sirens are designated Class A or Class B. A Class A siren is loud enough that it can be mounted nearly anywhere on a vehicle. Class B sirens are not as loud and must be mounted on a plane parallel to the level roadway and parallel to the direction the vehicle travels when driving in a straight line.
   BULLET::::- Fire alert: 3 15-second continuous tones separated by 7-second intervals. All firemen of volunteer fire brigades should report to their fire station immediately. This signal is used less and less, as many fire brigades alert their members by use of radio.
  
  Section::::Civil defense sirens around the world.:Europe.:Belgium.
   Fire sirens are often called "fire whistles", "fire alarms", or "fire horns". Although there is no standard signaling of fire sirens, some utilize codes to inform firefighters of the location of the fire. Civil defense sirens also used as fire sirens often can produce an alternating "hi-lo" signal (similar to emergency vehicles in many European countries) as the fire signal, or a slow wail (typically 3x) as to not confuse the public with the standard civil defense signals of alert (steady tone) and attack (fast wavering tone). Fire sirens are often tested once a day at noon and are also called "noon sirens" or "noon whistles".
  
presuppositions: Emergency sirens sound the same within the same country.  All emergency sirens in the US sound the same, and all emergency sirens in Europe sound the same.
corrections: Emergency sirens sound different even within the same country.  Different companies make sirens that sound different.
raw_presuppositions: Emergency sirens sound the same within the same country.  All emergency sirens in the US sound the same, and all emergency sirens in Europe sound the same. All emergency sirens in the US sound the same, and all emergency sirens in Europe sound the same.
raw_corrections: Emergency sirens sound different even within the same country.  Different companies make sirens that sound different. Different companies make sirens that sound different.