# Confused about string instruments and standing waves

• bt1740
In summary, the conversation discusses the need to calculate the frequencies of the first four harmonics for a banjo project. The speaker suggests using physics rather than equations from a book and mentions the importance of understanding nodes and antinodes in creating a correct sine wave. They also mention the role of string attachment in determining nodes. The recommended approach is to sketch out the possible sine waves for different numbers of nodes and identify a pattern.
bt1740
So I made a banjo for my project and now I need to do the calculations.
Well since its a string instrument I have to find the frequencies of the first four harmonics, I already have the fundamental frequency.
Is it fine to use:
fn = nf1

Not sure because I thought that was for open end air columns?

Welcome to PF;
Do not go by equations you find in a book - go by the physics.
You know that the fundamental and all harmonics must form sine waves - you should be able to sketch a sine wave.

Your banjo has strings - is the string attached at both ends or just one?
The attached ends of the string must remain still - so the amplitude there is zero: they are nodes.
You get an antinode (max amplitude) between every two nodes.
Each harmonic up adds a node.

So sketch out the possible sine wave for 2 nodes, then for three nodes, and so on until you see a pattern.

## 1. What is a string instrument?

A string instrument is a musical instrument that produces sound through the vibration of strings. These strings are typically made of materials such as nylon, steel, or gut, and are stretched between two points on the instrument. When the strings are plucked, strummed, or bowed, they produce vibrations that create sound waves and produce music.

## 2. How do string instruments produce sound?

String instruments produce sound through the vibration of strings. When a string is plucked, it creates a disturbance in the air molecules around it, creating a sound wave. This sound wave then travels through the air and into our ears, where it is interpreted as music. The length, thickness, and tension of the string all affect the pitch and tone of the sound produced.

## 3. What are standing waves?

Standing waves are a phenomenon that occurs when two waves of the same frequency and amplitude travel in opposite directions and interfere with each other. This creates a stationary wave pattern with points of maximum and minimum amplitude, known as nodes and antinodes. In string instruments, standing waves are created when the string vibrates at certain frequencies, producing different musical notes.

## 4. How do standing waves relate to string instruments?

Standing waves play a crucial role in the production of sound in string instruments. As the string vibrates, it creates standing waves that determine the pitch and tone of the sound produced. By adjusting the length, thickness, and tension of the string, musicians can change the frequency of the standing waves and produce different musical notes.

## 5. How do string instruments use harmonics and overtones?

Harmonics and overtones are higher frequency standing waves that are produced along with the fundamental frequency (the lowest frequency produced) in a string instrument. By lightly touching the string at certain points, musicians can produce different harmonics and overtones, creating a richer and more complex sound. These harmonics and overtones are what give string instruments their unique and beautiful timbre.

Replies
19
Views
708
Replies
6
Views
1K
Replies
1
Views
2K
Replies
5
Views
1K
Replies
1
Views
1K
Replies
2
Views
1K
Replies
3
Views
6K
Replies
5
Views
6K
Replies
31
Views
3K
Replies
11
Views
3K