South City Substation; 1971-72
August 25, 2018
I’ve never had any of these new-fangled noise-cancelling headphones but they must work on the same principle as these brick cones.
By positioning complimentary oscillators (humming transformers) with their noise directed at one another their longitudinal sound waves will act to cancel one another out. To test this, stand at the ‘node’ directly between to cones and see if it’s much quieter than if you move toward one or the other.
Same principle is used in factories to keep the noise down. Let loud machines calm each other down rather than form a joint assault on human ears.
That answer should get me full marks in fifth form science.
Ref. Upright! Exploring Dunedin’s Built Heritage, Facebook
Ref. Google maps
Ref. See Through Windows Ltd.; “So, I’m not going to pretend I know anything about the Crawford St/Vogel St Substation…”
Happily I have no such qualms about pretending to know all sorts of things. Otherwise there would be very few blog posts! 🙂 🙂