TubeNet

Eventide made a statement in their most recent blog post that I'm now super curious about.

Buys Ballot, a Dutchman, demonstrated the Doppler Effect on sound waves by having six tubas play the same sustained note while perched on the front of a speeding locomotive.

https://www.eventideaudio.com/blog/aagn ... harmonizer

While I'd love to believe this, I'm struggling to find a citation for it, and sousaphone's didn't exist in 1845. What's the true origin of that photo?

That type of electric locomotive WAY postdates 1845, too. Also the clothes look 1940's or '50's.

10253, Class EP-2, was built by General Electric in September 1919, #6981. It was renumbered E4 on March 2, 1939, and scrapped in January 1961.

Also, Buys apparently "assembled a group of horn players and placed ­them in an open cart attached to a locomotive."
Horns are much more probable in 1845...

The origin was a corollary experiment to Doppler's premise that waves, whether sound or light or anything else, have compression, or perceived higher frequency, in front of a source moving towards a recipient, and have rarefaction, or perceived lower frequency, behind a source moving away from a recipient.

The original experiment noted was to test the math on how much the perceived frequency shift is. The real experiment was something along these lines: a tuba player was seated on a flat car of a train traveling at a constant velocity and the player playing a steady pitch, usually referred to as @ 75Hz. A second player was seated stationary next to the track playing the same pitch. The experiment measured the heterodyning over time of the two to see if the theoretical mathematics to derive the length of the heterodyning cycle was correct.

https://www.homeworklib.com/question/76 ... eriments-a