Here is a map i've made, and some of the locations have videos and articles linked under them. If you have any locations to add to the map, please post them either here, or on the map's topic. Please keep all other info here.
viewtopic.php?f=24&t=27526
In other news, I have found multiple articles that claim the sirens were put up in the 40's, under Dutch rule. This suggests they came from a Dutch manufacturer. Wouldn't surprise me considering there are a number of other sirens in the region that are foreign.
https://jogjaraya.id/post/sirine-gaok.html
I also discovered another system of these weird sirens, in Malang, which may or may not still be up. I've only been able to find one siren, which is gone in streetview, but newer articles suggests it's been put back up.
https://www.terakota.id/menara-garling-riwayatmu-kini/
As far as I know, most of the sirens in Yogyakarta are still used for religious purposes.
And finally, here is another video of one of the rotating sirens, in Yogyakarta. This siren in particular is on top of Hotel Toegoe (on the map). This shows how directional they are.
https://www.youtube.com/watch?v=P-ExatX1NEM