# Questions tagged [harmonics]

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1 vote
45 views

### Human error in wave experiment

I am trying to see what the fundamental frequency of a string is by slowly increasing the frequency on a function generator. This experiment relies on the experimenter to record the frequency as soon ...
• 27
37 views

### Understanding Loop Formation in a Plucked String

I have a question regarding the formation of loops when a string is plucked at different fractional lengths. In a book I referenced, it is stated that plucking a string at 1/6 of its length produces 3 ...
43 views

### Why am I getting this derivation of time period of pendulum in an accelerated frame wrong? [closed]

We are working in the frame of the cart and we are trying to obtain the $\tau=k\theta$ form. So, let's write the $\tau=I_{axis}\alpha$ first for a small deviation $\theta$ from the vartical. (The ...
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5k views

### Feynman claimed "The ear is not very sensitive to the relative phases of the harmonics." Is that true?

In The Feynman Lectures on Physics, Dr. Richard Feynman claimed that the ear (I assume he meant the human ear) is not sensitive to the relative phases of harmonics. However, I was asked to test ...
• 145
1 vote
37 views

### Question about waves in a fixed string

consider a string that is fixed at both ends. This string is connected to a metal stick. When I hit the metal stick, sound waves (longitudinal and transversal ?) will propagate trough the metal and ...
• 308
1 vote
41 views

### Dispersion relation for non-harmonic waves

This question is related to my previous one. The entire linear theory of waves is built on dispersion relations, which represent the algebraic dependence of frequency on wave number. That is we ...
1 vote
41 views

### What is the name of this pendulum? [closed]

What is the name of a pendulum with two parallel string hung vertical to a rod, and giving the rod an initial force would make it swing left and right, doing simple harmonic motion? What is the ...
37 views

### Is there a class of phenomena the description of which is not limited to the study of the properties of individual harmonic waves?

There are lots of examples of oscillatory phenomena in nature the description of which boils down to simple harmonic behavior, i.e. to Cosine/Sine/Complex Exp. This answer explains that we use sines ...
1 vote
382 views

### Is this image on harmonics and overtones wrong?

I saw this image and believed this to be the definition of what the relationship between harmonics and overtones to be in strings, closed pipes and open pipes. That the $n^{th}$ harmonic = $n-1^{th}$ ...
• 2,356
23 views

### How was the $\Gamma _\mu$ be used as a gauge condition in the Generalized Harmonic formulation $R_{\mu\nu}$

I'm watching a video(ICTP-SAIFR Numerical Relativity by Sascha Husa) where he mentioned that R_{\mu\nu} =-\frac{1}{2} g^{\lambda \rho} g_{\mu\nu,\lambda \rho} +\nabla_{ (\mu }\Gamma_{\nu)} +\...
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50 views

### How is a resonant bandpass filter similar/different from a damped mass-spring oscillator? They seem to behave both similar and different in testing

Background I am using resonant bandpass filters as musical oscillators. One can excite an array of them at harmonic frequencies and given Q values for a note by, for example, running a burst of noise ...
• 321
1 vote
55 views

### String vibration dimensions

We're all familiar with the typical diagrams of standing waves of a string, as in this image from Wikipedia: The thing that bothers me is that they ignore the reality that the string is vibrating in ...
42 views

### Observations of harmonics in gravitational wave experiments

In gravitational wave astronomy, we usually observe $f_{GW}=2f_K$ (gravitational wave frequency twice the orbital frequency from keplerian motion). However, we also know there should be harmonics with ...
• 6,611
1 vote
95 views

### Change in Frequency while Tearing Paper

Let us assume you have a 30cm strip of paper, and you tear it lengthwise. Let us abbreviate the frequency produced when you reach the end of the paper as $f_2$ and the frequency of sound heard when ...
52 views

### Air Columns non-resonant frequencies

I understand that both open and closed-end air columns have many resonant frequencies, called harmonics and a fundamental frequency. At these frequencies, we expect to observe standing waves of ...
• 11
31 views

### Loss of energy during harmonic resonance

I have been trying to determine the function describing how energy is lost during harmonic resonance: Say an input of energy at the resonant frequency of a closed resonator. I know the following ...
93 views

### How does a string thickness affect the frequency of its harmonics?

The harmonics of a theoretically infinitely small diameter string are pure integer multiples of the fundamental frequency. However, a real string has a thickness, and when vibrating in a harmonic, the ...
1 vote
42 views

### Natural Harmonics on a String

Consider the Dirichlet boundary value problem of a guitar string stretched between two fixed points which is made to oscillate by pinching and releasing the string. It can be shown in quite ...
• 1,410
1 vote
47 views

### Viewing String Oscillations with a Camera

In this video, a demonstrator shows normal modes on a string. If one is doing this with a high speed camera, how many frames per second does one need to view the oscillations? My intuition was that ...
• 1,410
66 views

### What is heard when a tuning fork is struck?

When a tuning fork is struck I hear two tones. From a distance I can hear a high octave frequency of the pitch of the tuning fork. Though, if I listen to it closely (closer to my ears), I also hear a ...
• 109
1k views

### Why is the energy of the harmonics in a vibrating string not infinitesimal?

When you pluck a guitar string, initially the vibration is chaotic and complex, but the components of the vibration that aren't eigenmodes die out over time due destructive interference. This ...
• 217
100 views

### Phase difference of standing waves

The phase difference of a standing wave is zero. The above statement is found online when searching about standing waves. However, it doesn't make much sense to me. Consider the above diagram of a ...
1 vote
98 views

### Harmonics in closed and open pipes

What exactly would happen if we sent a frequency that was not one of the harmonics into a closed and open pipe? What would happen if we gradually increased this frequency? From my understanding, I ...
43 views

### Phase difference problem

What's the phase difference between A and B on the following diagram. Where it is a standing wave. This question doesn't even make sense to me as from watching animations of standing waves, points A ...
219 views

### Clarifications on standing waves within a pipe?

Standing waves are causing great confusion for me. I have read many answers on stackexchange. However, I still don't understand standing waves within closed and open tubes. Problem 1. I struggle to ...
1 vote
61 views

### How is wavelength defined for standing waves?

How is wavelength defined for standing waves? I cannot understand why the first harmonic is half a wavelength rather than a full wavelength. I see how wavelength is defined for progressive waves but I ...
272 views

### Why do water sounds different at different levels?

I observed that when we fill a water bottle it sounds different at different levels of height. means it sounds different while filling at $\frac{1}4$ level and different at $\frac{1}2$. I just want to ...
• 77
466 views

### How to create a standing wave that doesn't oscillate with the fundamental frequency?

Is there a way to make the string on my violin vibrate in an overtone frequency instead of the fundamental frequency?
26 views

### First Harmonic/Closed Tube/Net Transfer of Energy

Standing waves have no net transfer of energy. But, when watching simulations of the first harmonic for a closed tube, I see what looks like a transfer of energy - the particles clearly appear to ...
• 463
1 vote
108 views

### Can a pendulum have detectable harmonic frequencies

Can a pendulum produce harmonic frequencies? Like could I detect harmonic frequencies if I had a sensor on the pendulum?
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1 vote
168 views

### Why is time harmonic follow the form of $e^{-i\omega t}$, not $e^{i\omega t}$? [closed]

In physics, when we solve an PDE or ODE, the solution usually has the form of $$f=C_+e^{i\lambda x}+C_-e^{-i\lambda x}$$ and the "causility" will eliminate one ...
• 19
558 views

### What do I hear when listening to a computer-generated sine wave?

When I use a sine-wave generator (such as this one), I give credit to the software and my hardware that a pure sine wave is produced (as close as is technologically possible) — that is, no harmonics. ...
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73 views

### In what respect does the wave pattern of a noise and music differ?

Does the wave pattern of musical sounds contain only harmonics (other than the fundamental frequency) while noise contains random overtones (that are not harmonics)?
• 1,066
210 views

### The definition of "total curvature" for a scalar field

In Modern Electrodynamics, Zangwill remarks that the total curvature vanishes at every point where $\nabla^2 \varphi = 0$. Now my question(s): how is "total curvature" defined for a scalar ...
• 1,095
88 views

### What is the simplest PDE/ODE/model I can use to understand how nonlinearities can lead to leakage of energy to higher harmonics in an oscillator?

I came across this problem in the study of surface waves in an oscillating cylindrical vessel of liquid. There are various eigenmodes described using Bessel functions, and energy transfer can happen ...
1 vote
84 views

### Is there a 'better' tuning frequency than 440 Hz? [closed]

My apologize if this question is a bit broad or open ended but I'm asking here rather than a music forum for two reasons: I'm trying to gain a better understanding of the physics of sound and ...
1k views

### What are harmonic waves?

I am studying waves for my examination. Harmonic waves is also in my syllabus and I don't know what it is. I searched for it on google and got two possibly different answers. One answer is from en....
• 121
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### HOW are harmonics generated in longitudinal waves on the particle level?

I have been looking through the physics.se and all over the internet for weeks now honestly, and I still don't understand how harmonics are formatted on the particle level. Yes, I know that only ...
• 185
46 views

### The cause of higher harmonics amplitude drop in an air column?

In the case of the real life string, I believe I understand the cause of the amplitude drop as we go into higher harmonics: the bendability of the string is not infinite and as we get lower ...
• 185
1 vote
37 views

### Length of a water column executing SHM in a U-shaped Tube

I was watching the lecture 30 of Walter Lewin ( 8.01 ). Here is a link: https://youtu.be/hAYeA3Wwb4U At 29:30, when he was describing the SHM of water in a U shaped tube. Lewin says that for the ...
• 11
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### Does rope in a standing wave expand and contract as it moves between being straight vs sine?

Images of standing waves often show two people using a jump rope. The shape of the rope goes from straight to waves to straight, then a sine wave the other way and then straight again as it repeats. ...
82 views

### Why only harmonics allowed in the Casimir effect?

My question is really a request for an intuitive explanation as to why only harmonic frequencies of photons allowed between two conduction plates. Why do the plates have to be conductive? And can real ...
• 85
195 views

### Is timbre a physical noumenon or a perceptual phenomenon? [closed]

I have a question relating the "timbre" of a sound, namely what is exactly and exhaustively defined by this word? Most definitions that I come across seem somewhat loose as "the color ...
• 185
1 vote
554 views

### How can I calculate the number of nodes on a plucked string?

Given the length of the guitar string, can you predict the number of nodes that would exist on that string? My textbook says that there are an infinite number of harmonics that can be created when a ...
1 vote
195 views

### How does one apply the phase change of $π$ on reflection at the rigid end of a string?

Consider a string, with a free end $P$ and another end $Q$ which is rigidly fixed. Now, we start oscillating the point $P$ (with $0$ initial phase difference) and a wave starts traveling(in the ...
141 views

### Does the standing wave equation proof require $\ell=Nλ$? [closed]

Consider two identical sources $S_1$ and $S_2$ of waves, separated by a distance $\ell$ (as shown in the figure). The sources produce waves in opposite directions(and towards each other). Now, ...
1k views

### Why does an antinode form at the open end of an organ pipe?

I recently learnt about reflection of waves in various media and the resultant standing waves formed. In a string which is tied at an end, the wave formed reflects with a phase difference of 180 (at ...
65 views

### How to calculate the overall harmonics of a system of tubes?

Let's say there is a tube closed at one and and open from the other. The open end is connected to another tube (of smaller diameter) which is open from both ends. How can I calculate the overall ...
214 views

### What exactly happens, step by step, in string harmonics?

I know that a string when plucked shows harmonics but I do not really understand how. Like, I understand resonating air column and how standing waves are formed there, but I can't seem to get the step ...
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