![]() At some point the sound will be almost as loud in all directions. The lower the frequency the sound, the less it will tend to adhere to this directional principle. The current siren can be pointed in a specific direction and the siren will be significantly louder in that direction than to the sides or rear. It is this phenomenon that we desired to exploit with a new siren.Īnother important phenomenon of lower frequency sound is that it is not as directional as higher frequencies. You hear the low frequency bass and drums long before the vehicle pulls up next to you, but even when the vehicle is next to you, you can not hear the melody or other parts of the music. You have probably seen this demonstrated with “boom box” cars. Lower frequency sound penetrates solid objects better than higher frequency sound. However, this does not make it the best frequency to penetrate a well sealed and insulated motor vehicle. I was told casually by one expert in the field that this range was chosen due to it being the range of frequency that is best heard by humans and remains the best heard as hearing diminishes with age. These tones encompass the upper mid-range of human hearing. We found that the Society of Automotive Engineers requires wail and yelp sirens to be between 650 Hz at the low end to 2000 Hz at the top end. The first thing we did was examine the frequency (or pitch) of the current siren. ![]() We looked into technologies that could make the siren more effective. It was determined that modern vehicles are much tighter in construction and have improved seals and insulation that effectively blocks more sound transmission than vehicles of even just 10 years ago. We had determined from observation on-duty as a siren listener and off-duty as a signal receiver that sirens did not seem to be as effective today as they used to be. While we were examining the visual warning signals for improvement we also decided to examine the audible signals to determine if there was any way to improve these signals. Jim Wells, which evaluated and selected lighting and sirens for their use. The idea was one of many that came about in a project, overseen by Lt. For those who may not know, the system was designed at the request of law enforcement, specifically the Florida Highway Patrol. No siren can overcome idiots and people whose heads are up their.rears. The Rumbler is a supplemental siren designed to use lo-frequency tones for penetrating into other motor vehicles where ordinary sirens fail. The Rumbler just broadens the frequency range. The Rumbler does not stop your normal siren tone from being emitted in full strength from the normal is still there and can be heard. I am not a sound engineer, but it does make some sense to me. Larry told me that dual tone sirens, while noisy, were less effective than a single tone because the two tones often "cancelled" each other out (frequencies and such). Among things we talked about was dual tone sirens (and why FedSig didn't offer any). ![]() I have spoken to the engineer who designed the Rumbler, Larry Block. The Rumbler's amp unit will fit into any console plate that would fit one of the older SMC1-SMC5 SignalMaster controllers. Installation is not really hard, but does require a ground activation trigger, power, ground, and running two additional sets of speaker cables. It takes the siren signal and then synthesiszes it and amplifies it before sending it to its two lo-freq speakers. The Rumbler installs by interrupting and then completing the circuit from "normal" siren amp to speaker. Not to come off like a butt, but the OP is looking for informed opinions from those who have actually used the system or at least heard it.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |