California and Hi-Lo siren tone

[Maxim2Eng]

Reliving my childhood on Netflix…been watching Route 66 (1960-64): cool Vette (1960-63 models), cool cats and cool music (still love the iconic theme by Nelson Riddle). Watching Martin Miller as Todd Styles naturally led me to revisit my boyhood fav, Adam 12. It wasn’t until season 2 the radio and siren were shown on screen (1970, I was a sophomore in high school and on the volunteer fire department). (Of course, all siren sounds were dubbed in at post-production.)



Clearly a FedSig PA-20 Interceptor with Hi-Lo, and a frequent topic in this forum of Vintage and Collectible. Cool!! But I seem to recall a thread where CHP required FS to eliminate Hi-Lo for their vehicles. Did I misremember? What about LA? Was it because they could tie the Motorola radio and mic into the PA/Radio functions of the siren? Cali codes are specific and different. What’s the lowdown? Inquiring minds want to know!

 

[CHIEFOPS]

HI-LO was/is not a tone authorized by the Cal Veh Code. Agencies would special order their sirens without that function or disable them in sirens that had it, either electronically or by locking out that selector position. The 'common mic' setup was unrelated and not Cal-specific, many agencies configured it to simply to eliminate a 2nd mic and dangling cord.

 

[Maxim2Eng]

At least I didn’t misremember…I was hoping someone with specific knowledge of LAPD from the era could comment. Even in KY where I was working for an outfitter, we installed a lot of 2-way radio interconnects, usually for larger agencies. It was also a feature specific to the PA-20 and not the PA-15 which had a separate hard-wired mic.

 

[167]

HI-LO was/is not a tone authorized by the Cal Veh Code. Agencies would special order their sirens without that function or disable them in sirens that had it, either electronically or by locking out that selector position. The 'common mic' setup was unrelated and not Cal-specific, many agencies configured it to simply to eliminate a 2nd mic and dangling cord.

This is true in many States. I know TN specifically only recognizes Wail and Yelp. Even so, I'm not aware of any agencies disabling other tones.

 

[CD3]

Our Agency in CA ran a few of these PA20's The selector knob was locked so it couldn't be turned to Hi-lo. But It is now coming into CA as a evacuation tone, many agencies both police & fire have the tone on a separate button. This started several years ago after the many huge wildfires. BUT, none of the agencies or the state has put out notices of this siren tone to the general public.

 

[Wailer]

Reliving my childhood on Netflix…been watching Route 66 (1960-64): cool Vette (1960-63 models), cool cats and cool music (still love the iconic theme by Nelson Riddle). Watching Martin Miller as Todd Styles naturally led me to revisit my boyhood fav, Adam 12. It wasn’t until season 2 the radio and siren were shown on screen (1970, I was a sophomore in high school and on the volunteer fire department). (Of course, all siren sounds were dubbed in at post-production.)

View attachment 246550

Clearly a FedSig PA-20 Interceptor with Hi-Lo, and a frequent topic in this forum of Vintage and Collectible. Cool!! But I seem to recall a thread where CHP required FS to eliminate Hi-Lo for their vehicles. Did I misremember? What about LA? Was it because they could tie the Motorola radio and mic into the PA/Radio functions of the siren? Cali codes are specific and different. What’s the lowdown? Inquiring minds want to know!

The PA20A has the hi-lo tone. The PA20 has the alert tone. I have both, and they have completely different circuit boards.

The siren sound that was dubbed in for the Adam 12 patrol car was a recording of a PA20 running in manual mode, and in drive by scenes the wail tone could be heard.

The only TV show I heard a hi-lo tone in would be 'Emergency'. In some scenes of later episodes a hi-lo horn (not a siren) is heard when the squad goes through an intersection. And like all other sounds, it was dubbed in during post production.

 

[JohnMarcson]

LA County/City got around the high low restriction by mounting what essentially was a form of Martin horns on their squads (county) and sometimes their ambulances (city). This is essentially two air horns that alternate blasts at different tones. I believe the way they justified it was another siren was already running so this was technically considered an air horn, not a siren. I always thought it was pretty clever that the high low air horns were sneaking by on the exception that they were, in fact, a horn not a siren. I was told that there was a local company in California making these high low air horns, I cannot remember exactly who it was. Regardless, most modern siren systems come with an option to only use California compliant tones or to disable non-compliant tones.

FIAMM 12V Sirens for Emergency Services - Fiammhorns.com

Electro- and pneumatic acoustic devices for priority vehicles. Fire Brigade- Ambulance- and Police sirens.

www.fiammhorns.com

MARTIN-HORN® 2097 GM » Max B. Martin GmbH & Co. KG

 

[Maxim2Eng]

Interesting! I had a set of air horns (a kit from Italy) on my vehicle in high school and arranged the hoses to produce a high/low sound. My last siren was a PA2100 and I found the high/low to be most effective at highway speeds.

 

[allen5565]

From this September, 2010 post on the subject:

LACoFD & LAFD Hi-Lo Air Horns

Several people have asked about the hi-lo horns used on "Squad 51", wanting to know if they were electronic. They are not. They are air horns. Here are some links for the horns in use on LACo & LAFD vehicles: LACo: LACo is using 2 trumpets, but it sounds like LA City may be using 4...

elightbars.org

"2. The horns are not Martin Horns; they are Stebel for LACo and Fiamm for LAFD. The Stebel use non-Stebel trumpets (Stebel use a composite trumpet pair, and these are metal), and the Fiamm sets use Fiamm trumpets, either 2 or 4. LACo typically use somewhat higher frequencies than LAFD. That is a matter of preference. I do not know who makes the LACo trumpets. They are adjustable, and I have seen 4 used, adjusted to produce a tremolo, sounding exactly like the Martin 2297. The seller will not reveal who makes them."

 

[SoloRTP]

To clarify:

In the 1950s, when the first electronic sirens were coming out, someone realized that the Wail tone speed control could be varied, producing a faster cycle. Called "Yelp," it rapidly became popular -- but it sounded similar to a variable-pitch whistle.

Whistles being used for warning signals were a Big Bad No-No in the California Vehicle Code, because (wait for it) they sounded like steam engine whistles.

Something HAD to be done, and the Legislature amended the CVC to specify siren tones of Wail and Yelp. HORNS were not mentioned as public safety warning signals, because when a suggestion was made to do so, someone pointed out that big trucks had air horns in sets, and European cars often had air horns run off of a little compressor. They decided to avoid the joy of figuring out how to regulate them. They said "shall not emit an unusually harsh or annoying sound" and ran off to get drunk, and hid under the covers when tune-playing horns (yeee-haw!) came on the market.

And that's how things were for the following decades.

Hi-Lo has never been popular in the US, and has largely fallen out of use in the UK. They still refer to "Blues and Twos" when they fire up the disco lights and music, but they are mostly using Wail and Yelp when they do.

Speaking of "Emergency!", note that the theme song is a marriage of Hi-Lo horns and the SCU tones so familiar to us all . . .

 

[Davr]

When I began my professional career in the late 70s, we provided ES/EMS to communities outside our primary response area, and in one town the board voted make it illegal for emergency vehicles to use the Hi-Lo tones when responding to a call within the township. The community has a large population of elderly Holocaust survivors and the local government received many complaints about the siren mode, making people frightened and have flashbacks.
At the time, I was doing installs as a part time gig, and the company doing the primary installs sometimes subbed work to me; whenever I'd get a vehicle from that town I had to install a bolt or screw on the siren box to physically prevent the selector to move beyond welp.
Ironically, a policy was adopted by another community (where the airport was located), that vehicles responding to the airport for inbound aircraft emergencies were mandated to respond using their hi - lo sirens... I don't know why, and that 'mandate' faded away over time. -- (There was even one brief period when airport responses were completely in a non emergency mode, bcs airport management felt it scared passengers and families awaiting boarding departing flights)