# Vibration and the Guitar

Overview:

Vibration and the Guitar

If you place your hand on the body of an acoustic guitar while someone is playing music you will feel it vibrate.

This is because molecules move back and forth and their pressure varies up and down by very small amounts. The amount of times the molecules vibrate per second is a frequency and depending on how fast the molecules vibrate the sound will change in pitch.

For example, if a particular guitar string plays an A chord when it is strummed it is vibrating 110 vibrations per second or 110 Hz. An E string however, vibrates 83Hz and is the lowest note on the guitar.

## Pitch and Vibration

Pitch is how we perceive a sound based on a frequency-related scale. On the guitar there are six strings, and many different ways to tune them. We will refer to the most common:

String 1 = High E (this is the highest pitch and thinnest string)

String 2 = B

String 3 = G

String 4 = D

String 5 = A

String 6 = Low E (this is the lowest pitch and thickest string)

The pitch of a vibrating string depends on a few things, similar to the tuning fork, the pitch depends on the string’s:

Mass: If the sting is more massive it will vibrate more slowly and produce a lower pitched sound. If it is thin then it will vibrate faster and produce a higher pitched sound.

Length: The frequency can change depending on the length of the string. Having a shorter length makes it have a higher pitch. That’s why when you play a string open it is lower than when you press your finger down on a fret and play the string.

The pitch in the case of the guitar is also dependant on the tension of the string and the mode of vibration.

The guitar transmits vibration from the strings through the bridge of the guitar to the body. The body of the guitar serves as a large surface where air can move back and forth and amplify the sound.

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