User name fmagrao's sound 80761__fmagrao__siren was stretched, put in a sampler and played as described but of varying duration and it would appear that there is an optimum frequency range for these sirens. I will create a lower frequency version in due course and a foghorn/siren hybrid. The sound features on the following track along with other uncredited sounds downloaded from this site and i am genuinely grateful for all those contributions. Https://soundcloud. Com/klaxonite/klaxonite-3-190415.
This frequency is 136. 1 hz, or a c# if a=432hz. C# is often considered the "om tone", as there is some evidence that tibetan buddhist monks and others base their chants on this note. More info here: http://sonicfabric. Blogspot. Com/2012/01/432-hz-pythagoras-and-om-1361-edition. Html.