ARCHIVED: Mystery Sirens (2008-3/2021)

[DJ2226]

That's a single phase Model 5. They are pretty rare considering most single phase Model 5s and 3s are 12 port.

[Arteelx]

No, it's single tone, so either a 3V8(H), 7V8(B) or 10V.

You guys have been very helpful! I'm starting to wonder if this really is a single-tone siren, or not. I went to Sentry's webpage, and I learned that their two-tone sirens have tones at 460 & 920 Hz. This means that the high tone is exactly 2X the low tone. (This is news to me because I always thought that dual-toned sirens created a chord, rather than two octaves of the same note.) If you look at my original posting, the spectrograph clearly shows a second tone that is 2X the lower tone during the spool-down. I assumed that this was simply a harmonic of a singe-tone siren since it's very hard to produce a pure sine wave...but now I'm wondering if perhaps that is the second note from a two-toned Sentry unit. Also, I definitely measured the low tone at 471.7 Hz, rather than Sentry's published value of 460 Hz. This is a difference of about 2.5%. Is it typical for an electromechanical siren to be off from design by this much?

[Arteelx]

I went to Sentry's website, and I downloaded their sample sound files for the 10V and the 10V2T. Lo and behold, the low frequencies in both cases are around 469-472 Hz, rather than the published value of 460 Hz. This matches perfectly to what I'm hearing at my house. Also, the 10V and the 10VT2 look nearly identical in the analysis. In both cases, a high tone shows up at a frequency of exactly 2X the low tone...in one case, it's due to harmonics...in the other case, it's due to the existence of a second siren. So I think you guys hit the nail on the head. This is definitely a Sentry siren, and it could be either a single-tone or dual-tone model.

[justie1220]

wow never thought analyzing the hertz frequencies could help us to determine what a siren is!

[Brendan W]

I found this in Stillmore, Georgia. I'm thinking it's an ACA Screamer?

https://goo.gl/maps/SfT6NHpj86B2

[Luke]

That seems like the most logical option.

[Luke]

https://goo.gl/tgJ2rN

Looks like a Fedelcode 2 to me, but it sounds like a 5 (based on the times iv'e heard it sounding for fire calls). Any ideas?

[MaumeeStormMaster]

That's actually a Model 5. The top lid of the housing is actually not fully down on the siren, that's why the top louver is higher up. It might not even be fedelcode, it looks more like a Federal Signal. Still a cool find.

[Synther]

https://goo.gl/tgJ2rN

Looks like a Fedelcode 2 to me, but it sounds like a 5 (based on the times iv'e heard it sounding for fire calls). Any ideas?

Federal Signal Model 3 with the bottom shroud lowered. It's too small to be a Model 5, and it looks nothing like a Model 2. Nice find.

[Luke]

Thanks for your help!