View Full Version : Dual-tone siren

Richard Vyse
09-23-2009, 02:36 PM
In talking with Leo regarding the sirens in the Criterion, he says it has a Federal Interceptor and a dual-tone. I'm not sure what a dual-tone is and how it sounds. I've checked youtube for sound clips with no luck.
Does anyone have a sound clip of what a dual-tone sounds like and maybe a picture. Thanks

Rick Duffy
09-23-2009, 03:15 PM



Richard Vyse
09-23-2009, 03:47 PM
Man I hope it is this kind of siren. Thanks Mr. V.P. Duffy.:thumbsup:

Brendan Martin
09-23-2009, 04:56 PM
Richard this is the same siren that I have on my 63 Rescuer. It is on top of the roof and VERY loud! Because of the Dual Tone it also sounds very different as you can see from the You Tube video. It is almost eerie. Mine has a red light in the center that moves up and down. You will really enjoy this siren.:cool:

Steve Lichtman
09-23-2009, 06:25 PM
...You will really enjoy this siren.:cool:No doubt about it, he will enjoy it.

The dual-tone siren actually has two sets of rotors that are tuned slightly differently, so the two different tones rise and fall together but definately are different notes. They seemed to be very popular on M-M ambulances in that era, my Volunteer has one, too (as did the '69 Volunteer I owned many years ago).

Brendan Martin
09-23-2009, 06:35 PM
On our fire apparatus we use the Federal Q2B and on our ambulances we have electronic sirens mostly, Whelen, but the Federal 77 on my 63 makes the hair on the back of my neck stand up, I really have not heard anything quite like it! :D

John Dorgan - Deceased - 1938 - 2012
09-24-2009, 01:10 PM
Double tone Federal sirens.
Actually, they are called "Double tone" rather than dual tone sirens.
I presently have several in the process of restoration. If you are loking for one please let me know at john@sirenman.com I have a plain 77GB as well as a model 78.
John Dorgan