Rock Out With Physics

Physics Behind Playing the Guitar

The Guitar 

Jimi Hendrix, Steven Tyler,  Led Zeppelin. Absolute legends with their guitar playing ability. Songs like Dream On and When the Levee Breaks will forever be played and remembered for the guitar skills and sound these unbelievable talented people were able to reach. Everyone starts somewhere though, right? All these superstars had lessons and learned like the rest of us, but did any of them learn the actual physics behind the strings they pick? 

Waves 

The strings on the guitar are each made differently. Some are thicker, denser, and more tense than others. This allows the sound to vary for each string. A skinny more tense string will have a high pitch noise while a dense thick string will have a lower pitched sound. Why is that? The waves. When you pluck your guitar string you create a standing wave. The waves frequency will ultimately determine the pitch of the string. 

v = f

This is the equation for a standing wave where v is the speed of the wave, f is the frequency and the character is the wavelength. To calculate the wave for different pitched strings a new equation is needed that adds in the T (tension) to the equation and linear mass density, µ. The equation looks like this:

v =  T/µ

Overtones 

Overtones frequencies are multiplies of the first standing wave that combine to form a larger complex wave that gives a more vivid sound. The first initial sound you here is from the standing wave, but what makes the guitar sound so interesting and rich is the overtones that carry out the vibrations and frequency. The equation for the overtones adds a half a wavelength to each equation: 

1st overtone (l = 2/2) 

2nd overtone (l = 3/2) 

3rd overtone (l = 4/2) 

4th overtone (l = 5/2) 

Plucking the strings differently will also change what overtones you will hear. Plucking towards the middle will give off fundamental and odd multiple overtones, while plucking near the bridge of the guitar will give mostly even overtones (the very sharp high pitch noise). 

How I wish I could play as good as Led Zeppelin. Legends like them have mastered the guitar; they know the in's and the out's of the guitar. They can play with their eyes closed. However, I bet not many know the in's and out's of the physics behind the strings they rock out on. The guitar is a beautiful instrument and creates a wonderful sound. Without it we would be almost no where in the music world. Physics allows us to look deeper and understand better the things we love. 

ROCK ON!

Works Cited

Google Images, Google.

How Does a Guitar Work?

The Physics of Everyday Stuff - The Guitar.

“The Physics of Playing Guitar - Oscar Fernando Perez.” TED-Ed.

Seering, Adam. “How Strings Make Sound.” Physics of the Guitar | Guitar Building | High School Engineering | MIT OpenCourseWare, About MIT OpenCourseWare OCW Is a Free and Open Publication of Material from Thousands of MIT Courses, Covering the Entire MIT Curriculum. Learn More » © 2001–2016 Massachusetts Institute of Technology Your Use of the MIT OpenCourseWare Site and Materials Is Subject to Our Creative Commons License and Other Terms of Use.