Deep-toned siren in Poland

[500 AT fan]

Like the higher tone could be a toshiba and the lower tone could be something else

...I don't think any Toshibas even made it into Poland. Besides, those sound way different.

The siren in the first video probably uses two motors, as Daniel said. It's been mentioned in the past that these 3-9 port sirens used 2 motors, not usually sounded at the same time, though.

[CJ]

Lower numbers of ports take more revs to give the same sound output, it's to do with airflow which is also affected by pitch. That is why they seem to start at different times, plus the windup on the lower pitched end is slower for some reason or another.

And it's quite clearly one siren - with two motors.. Sentry do it so I don't see why not.

[orestis]

Hmm... I will go with the theory that there are two sirens. Take a look at this one.

http://www.youtube.com/watch?v=P6AgRVQh ... re=related

9 / 11 ports I guess.

[500 AT fan]

Interesting video.

Still doesn't sound quite the same as the sirens in the first videos, though.

And for the second video, am I the only one to notice there only seems to be one siren in the tower?

[Daniel]

If you look at the photo above, these sirens have two motors. The windup speeds would be slightly different. There are other Polish fire stations where two separate sirens are wired together, probably with the original use being one siren for civil defense and the other for fire.

http://www.youtube.com/watch?v=u7ZaUYEu ... re=related

Elektror, Siemens, and other companies built twin-motor sirens for this purpose, although many locations had two separate sirens. Before WWII in Germany, the low pitch was used for fire calls. Since the war, the low tone signal was abandoned in favor of three long blasts on a high tone, but many of the sirens (seen below) are still in place. Whether this is two sirens or a single, dual-motor one, I am convinced that both sounds are coming from the same location.

http://www.youtube.com/watch?v=uT3mHvRRbcU

http://www.youtube.com/watch?v=I8yIE1ZF ... re=related

http://www.youtube.com/watch?v=Qi0Ka6Nu ... re=channel