Strings in tension strain
Against powerful posts and
Await their calling.
Vibrating, they speak,
The sound echoes out across
All of space and time.
Too tense, and they break.
Too slack, and naught is produced.
Balance is the key.
I read a phenomenal statement last night.
A piano can have as many as 236 strings. Each string is under a tension of 160-200 pounds. In a regular piano, this translates to 18 tons. In a concert grand, it is close to 30 tons.1
Even a violin is subjected to 50 pounds of tension across its delicate frame.2
But tension alone does not produce music; these strings must move to create sound. Combine tension and motion, and you produce something that must be seen to be believed. Here is the vibration of a violin string in slow motion.
You don’t have to search for very long before finding articles full of gnarly equations on the physics of vibration, harmonics, and the Helmholtz corner (here’s an equation-free article on the bowing of a violin and another, aptly named “Why is the violin so hard to play?”). It came as no surprise then to find that physicist Richard Feynman had turned his keen mind to piano tuning. Feynman’s letter to his piano tuner can be found here. I hope the tuner could read equations.3
We can all be grateful for the technical wizardry of Stradivarius and Guarneri and Babcock’s cast-iron frames that would have kept Liszt from wrecking his pianos, but let’s turn again to the music that can be coaxed from these taut strings.
Image attribution: Piano strings, photo by Alan Levine from Strawberry, United States (Music Strings) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons, https://commons.wikimedia.org/wiki/File:Piano_strings_6.jpg