The Siren Board

As you may have seen me mention, my university uses a system of 4 ATIs. For weeks now, I've been hearing, multiple times per day, a roughly two-second long "pop" or "squeak" sound from the siren closest to my dorm. I only realized it was coming from the siren in the first place last week, when it happened while I was standing right by the building where it is mounted. Now I've got friends, knowing that I'm the siren expert, asking me what's going on. I've had to tell them I honestly don't know. Can you guys help me out here?

could be just a short internal test. it's trivial to design an amplifier that can test its own output circuit; most OEM automotive amplifiers can to this. they send a pop or tone to the speaker and check the current through the circuit (actually, the voltage across an inline resistance) and if it's within spec it assumes the speaker is OK.

Ok, thank you, but are you sure this is something that would happen daily, even hourly, even multiple times in an hour? Is that normal?

CTsirenhunter wrote:Ok, thank you, but are you sure this is something that would happen daily, even hourly, even multiple times in an hour? Is that normal?

While your university could probably setup the computer to poll the sirens that often, there is probably just excess voltage on the line or a little bit of a short somewhere. It likely isn't really hurting anything, and if it acts normally during tests I suppose it shouldn't be of any major concern.

Ok, thank you. I will go reassure my friends about it. I think they'll understand better than I do, being math/science/engineering people, which I am not...

Interesting questions.

I once parked at a shopping center across the road from one of Nashville's ATIs on test day.

I was close enough to hear a distinctive"pop" when the siren shut off.

Another time I heard one of the HPSS-32s in a park; when it cut off I heard what sounded like an echo coming back through the speakers.

Strange indeed!

Here's my idea... it may not even be close to being right, but is the system capable of broadcasting a live voice message? Like some of the pa-systems at many of our nations schools. Perhaps something is bumping the "talk" button on the microphone or maybe there's a "trigger-happy" person who is just bored and likes to push buttons. Its the only thing I can think of. 8)

Oh, it's capable of doing that all right, but we're not so irresponsible as to let it happen. I've never seen the central controls of the siren, but I'm sure they're quite secure. I'm sorry, but I think the first explanation in this thread is correct...

That sounds like ATI stuff... hope it works when you guys need it..

Really, you should let the people in charge of the siren system know about this (but maybe check out some of the other locations on campus to see whether they do it too). It could indicate a real problem that needs to be addressed.

Does it correlate to anything? Time of day, regularity, etc.? Inquiring technical mind wants to know...