<story><title>Finding the Air Cannon</title><url>https://www.twobraids.com/2024/01/air-cannon.html</url></story><parent_chain></parent_chain><comment><author>mdip</author><text>This is a clever approach and it got me wondering a few things.&lt;p&gt;An hour or so from where I live there have been complaints about an infrequent low rumbling sound for &lt;i&gt;years&lt;/i&gt;[0].  I&amp;#x27;d wondered -- at the time -- why you couldn&amp;#x27;t just do something like they do with the gunshot detectors to find the source of the sound[1].  I suspect there must be a technical&amp;#x2F;physics reason that I am not familiar with.  This article re-enforced that thinking for me -- I think I&amp;#x27;ve heard one of these air cannons, before (I have not heard the Windsor Hum), and its characteristics seem more like a gunshot kind of sound than what&amp;#x27;s described here but ... if you can record the time it starts from three different points (and all you&amp;#x27;re looking for is &amp;quot;an area roughly the size of a large factory&amp;quot; because it had always been suspected to be one of the plants along the river), wouldn&amp;#x27;t this approach have been simple&amp;#x2F;cheap enough to do to figure it out[2]?&lt;p&gt;[0] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.npr.org&amp;#x2F;2020&amp;#x2F;08&amp;#x2F;04&amp;#x2F;898853311&amp;#x2F;it-took-a-pandemic-mystery-of-windsor-hum-is-solved&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.npr.org&amp;#x2F;2020&amp;#x2F;08&amp;#x2F;04&amp;#x2F;898853311&amp;#x2F;it-took-a-pandemic-...&lt;/a&gt; -- it was solved because a steel plant shut down and the problem went away.&lt;p&gt;[1] Part of the problem was that a subset of the population could hear it and a subset of that population noticed it enough to be bothered about it so it kind of led to a large number of people dismissing complaints as &amp;quot;people who complain about WiFi signals harming their health&amp;quot;&lt;p&gt;[2] And if I answer my own question: I suspect it probably was and I suspect the reason it wasn&amp;#x27;t done is that nobody cared enough to do it, really. :)</text></comment>
<story><title>Finding the Air Cannon</title><url>https://www.twobraids.com/2024/01/air-cannon.html</url></story><parent_chain></parent_chain><comment><author>gwern</author><text>Fun historical trivia: shortly after winning the Nobel Prize, Bragg &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Lawrence_Bragg#Work_on_sound_ranging&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Lawrence_Bragg#Work_on_sound_r...&lt;/a&gt; spent WWI working on exactly this problem &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Artillery_sound_ranging&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Artillery_sound_ranging&lt;/a&gt;</text></comment>