Questions tagged [harmonics]

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Measuring the harmonics of a vibrating string

I have a string which is vibrating at a fixed frequency, say 1 kHz. I know it is vibrating in a purely first harmonic mode because of the (sinusoidal) drive function I am using. With a microphone I ...
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1answer
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Behaviour of 2 resonant tuning forks in a vacuum

The scenario is the following. Two perfectly tuned resonant tuning forks A,B are placed in the same vacuum. [ Ideally the experiment is conducted when both A&B are in free fall]. Tuning fork A is ...
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1answer
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Resonance frequency of a guitar

I have some questions for you about the resonance phenomenon in a guitar: Why resonance frequency are only full integer multiples of the natural frequency, such as 2 x, 3 x, or 4 x or 3 x, 5 x, or 7 ...
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Waves and guitar frets

I have a problem to solve for Physics III at university and I can't seem to understand how to solve this question. I have the fundamental frequency at $440$ Hz, $L=1$ m, and $ρ=0.002$ kg/m. After ...
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1answer
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Does electrical sawtooth wave actually produce sinusoidal oscillations at harmonic frequencies?

According to Fourier's theorem, we know that a sawtooth wave can be represented as a sum of sine waves. These sine waves we know as harmonics (in the context of sound). My understanding is that it is ...
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42 views

Harmonal density Probability changes?

I have been thinking about strings vibrating. we usually see a purely elastic string in modes of vibration as states of modes. I was thinking, what if we changed the length of the string dL such that ...
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2answers
63 views

What is the difference between $\omega$ and $\Omega$ in the equation $\Omega = \theta_o\omega\cos(\omega t +\delta)$?

The standard equation for any object moving in a linear simple harmonic motion (SHM) is $$x=A\sin(\omega t +\delta)$$ where $A$ is the amplitude, $\omega$ is the angular velocity. Likewise, converting ...
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Laplace transform for damped waves

In Zeidler's book on QFT, page 94 there is a definition for a Laplace transform that reads \begin{equation} (\mathcal{L} f)(\mathcal{E}) = \int_0^\infty e^{i\mathcal{E}t/\hbar}f(t) dt, \end{equation} ...
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7answers
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Why do higher harmonics have a lower amplitude than the fundamental frequency?

When we pluck a string, it vibrates in all possible modes of vibrations. The lowest frequency possible is the fundamental frequency and it is the most significant part of sound. But why do the ...
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1answer
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Question regarding open and closed air columns

I'm studying high school physics and I've encountered this question: An air column that is open at both ends has a distance of 24.0 cm from one resonant length to another. What is the wavelength ...
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1answer
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Why are there no even harmonics in a closed pipe?

I have seen a diagram on sites such as hyperphysics.com that show that there is a missing bit every time so that it makes every harmonic odd. I was hoping I could get a more intuitive explanation. We ...
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3answers
105 views

Relation between frequencies of different harmonies

I know the relation between frequencies of different harmonies is $$ f_n = n\times f_1 $$ but I'm heving trouble to develope the equation which proves this equality. can anyone please give me a lead ...
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1answer
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How do cavity resonators differ from tubes of uniform width?

I read that wine bottle produces sound when u blow sideways onto its rim because some frequencies of the white noise produced in your mouth gets amplified when they match the natural frequency of the ...
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1answer
45 views

Finding the conditions for a resonant (unique single mode) state in the wave equation

If we have a string of length $L$ in constant tension $T$ and we oscillate one of the extremes at the rate $\sin{\frac{\pi nc t}{L}}$, we observe in a lab that single harmonics are produced. I want to ...
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1answer
99 views

What is the relation between the fundamental frequency and a harmonic?

I am currently busy with a physics report about determining the speed of sound in air. In order to do this, I was told to use a tube that can extend or shorten in order to find the different harmonics ...
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1answer
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What causes this high frequency “noise” in HHG spectra?

Looking at high harmonic spectra, one can often see that peaks corresponding to higher harmonics look more and more noisy and seem to be drowned out by the noise. For example, one such spectrum is ...
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Are there any resonant frequency spectra that do not possess any harmonics?

I’m hoping that somebody can help clarify the following passage regarding standing waves and the systems that support them: Many systems that support standing waves have resonant frequency spectra ...
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1answer
307 views

Resonant frequencies in organ pipes

I have a series of doubts regarding the principle of organ pipes. For a given length of closed organ pipe there are various modes of vibration for the standing waves.I dont know if this is silly but ...
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16 views

Dependance of number of harmonics from force of collision

I recently found out that if hit something hard, it will produce all harmonics, but if hit with less and less force firstly low harmonics will disappear firstly and only high will stay. Why so?
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1answer
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Why are planet's maximal/minimal angular speed ratio harmonic?

See this Wikipedia page for Harmonices Mundi, a book by Kepler (yes, he was the one to discover the three Kepler's laws). The author writes: He found that the difference between the maximum and ...
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Why coupled oscillators tend to seek integer frequency ratios?

In this document, the author writes (page 225) Coupled oscillators have a tendency to seek frequency ratios which can be expressed as rational numbers with small numerators and denominators. For ...
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0answers
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Is there a way to know the non-zero coefficient of $\cot(\theta)$ expansion in spherical harmonics?

I'm currently trying to find an analytical solution to the Poisson equation for a given distribution using a multipole expansion. During this task, I found the radial expansion and everything else, ...
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2answers
89 views

How many linear combinations of harmonics or normal modes can describe the same periodic function as a Fourier series?

Please note that I am not asking how many terms in a linear combination can describe a specific periodic function but if given that there exist a set or linear combination of normal modes that ...
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Why can an inner product of an eigenvector also be used as an eigenvector?

In quote box below, there is an inner product of an angular momentum eigenvector. Why can you use this inner product as a new eigenvector for the next part of the work? And why do they "of course" ...
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37 views

Why a musical instrument's string oscillates with many frequencies? [duplicate]

I am trying to understand why when we play a note on a stringed instrument, not only it oscillates with it's fundamental frequency but also the multiples of that. For instance if you play a D on the ...
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1answer
110 views

Harmonics in a tube closed at one end

I have been learning about sound and how a tube closed at one end only seems to have odd harmonics. However, I have found that although clarinet follows this and plays only odd harmonics, saxophone ...
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1answer
462 views

De Broglie explanation of Bohr's second postulate. discrepancy of 2 times?

I am reading how de Broglie justified the 2nd postulate of Niels Bohr (i.e. angular momentum of an electron to be integral multiple of $\frac{h}{2\pi}$). I get his explanation of electron acting like ...
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2answers
151 views

Why the faster you spin the highest the pitch get in a whirly tube? [duplicate]

I would like to understand why the faster you spin, higher normal modes are excited This is the tube i'm talking about, i think it's used as a kid's toy: https://www.youtube.com/watch?v=eCOZxzO3FvE ...
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0answers
75 views

sounds of polygonal ring chimes of metal

Suppose we have a number of rings, each of them is constructed from some mass of wrought iron or steel: each ring is a polygon, which I would like to suppose is constructed without welding (so they ...
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1answer
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Integer multiples of fundamental time period? [closed]

If we define harmonics to be positive integer multiple of fundamental frequency What will we say to positive integer multiples of fundamental period?
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1answer
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Is the first harmonic the prevalent frequency? [closed]

Why, when we play a string, almost all of the energy we give them is ''used'' in the first harmonic (the fundamental frequency) rather than be distributed between all of them?
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4answers
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If all harmonics are generated by plucking, how does a guitar string produce a pure frequency sound?

A guitar is a plucked instrument and it is played by plucking a string at an off-centre point fixed at two ends. In general, Fourier analysis tells that all harmonics (the resonant frequencies of the ...
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2answers
67 views

Why are there these other “harmonics” (violin-specific terminology) in violins?

I've often read explanations of how standing waves form on the string of a violin and their harmonics but there is another phenomenon I've never seen explained: When you play certain notes, musicians ...
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3answers
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Why, in an open or half-open pipe, must an open end of a standing sound wave have a pressure of zero?

I believe this question was asked in some form before, but I'm not clear on the answer. If a sound wave must equal air pressure when it exits a tube, why is it possible that at many points after the ...
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1answer
143 views

Pulling a string with both ends fixed [duplicate]

Consider a string with both ends fixed. If somewhere in middle of it be pulled and released, how would it oscillate and what is it's equation? My solution assuming the result is a standing wave: The ...
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2answers
202 views

How is it possible that multiple overtones can exist at the same time?

I was wondering how it is possible for overtones to co-exist at the same time. When one pulls a string, it starts to oscillate and forms a standing wave with frequency $$f_0 = f$$ Additionally, ...
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1answer
111 views

How do we hear harmonics and how does it affect audio fidelity?

First and foremost, do we hear a sound wave as a sum of all the individual harmonics, at the fundamental frequency, or do we hear all the associated harmonics above the fundamental frequency and ...
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1answer
65 views

Can we consider oscillation of air column in the wind instruments as phonons subject to Bose- Einstein statistics ?

A flute is a wind instrument, which could be modelled as a resonance cylinder open at both ends. Any cylinder resonates at multiple frequencies. A skilful player produces a standing wave in the flute ...
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2answers
278 views

At what frequency does a string vibrate?

When a string with fixed ends vibrates (e.g. plucking a guitar string) Fourier Theorem says that the vibration can be expressed as a sum of its normal modes, which are sinusoidal vibrations with ...
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2answers
63 views

Which book would you recommend for a dummy wanting to start studying acoustics, out of interest?

I've been very into acoustics lately, specifically the harmonic series. I find it fascinating how the harmonic series works as a sort of guideline to harmony, and how we base tuning systems on trying ...
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1answer
416 views

Where do pure tones occur in nature, besides harmonics?

When you sound a tuning fork, you hear an pure tone/sine wave of usually 440Hz. Yesterday, I tried hitting a table knife made entirely from stainless steel against a grapefruit. When I held it up to ...
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1answer
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Are These Guitar Strings Demonstrating Subharmonics?

This video has a fair few instances where there is an exaggerated wiggling of the guitar strings. I rationalise this by saying its a similar effect to rotoscoping, like where wheels appear to spin ...
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2answers
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Is second harmonic generation a special case of high harmonic generation?

That might be a strange question, but while I was researching for these topics, I never found an explicit statement that would answer that question. (That might be because of the different ...
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4answers
315 views

If a guitar note is determined by the fundamental frequency, what is the relationship between this and octaves?

All the research I've been doing tells me that a guitar note is determined by the fundamental frequency played. But say you play an A on the open A string (110 Hz), and then play a higher octave A by ...
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How are overtones produced by plucking a string?

I read the following from wikipedia: When a string is plucked normally, the ear tends to hear the fundamental frequency most prominently, but the overall sound is also colored by the presence ...
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1answer
325 views

Why do two tubes with different lengths produce different frequencies?

I've learned that it has to do with harmonic frequencies and the relationship between length and wavelength in the equation $L = n(\frac{\lambda}2)$, but my question is why? If you were to blow air ...
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3answers
325 views

What does it mean that standing waves oscillate in phase?

What does it mean that all points between two adjacent nodes in a standing wave oscillate in phase? I sort of get what in phase means, it means that the peaks and troughs etc of 2 waves align. But how ...
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2answers
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On Harmonics In Physics

I am an IB physics student. I am very confused about the concept of first, second, third, etc harmonics. My questions are: How does a wave get from first to second harmonic, and from second ...
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A pure sine wave vs. the infinite sum of its harmonics

Is a pure sine wave equivalent to the sum of its every harmonic (up to infinity and without the fundamental lets assume)? Moreover, if it is so, is this the reason why all the harmonics are present ...
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What is fundamental frequency, how does it make sense?

I’m currently going through harmonics, and I do not at all understand the fundamental frequency. I understand that it is the simplest vibration of a string, but I don't understand how can it have ...