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10
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2answers
1k views

How can you make harmonics on a string? [duplicate]

For an oscillating string that is clamped at both ends (I am thinking of a guitar string specifically) there will be a standing wave with specific nodes and anti-nodes at defined $x$ positions. I ...
8
votes
3answers
354 views

Need mathematical explanation for different musical notes sound different on different instruments

I am not expert in music. There are number of musical instruments. One (especially a person who knows about music) can blindly recognize which instrument is being played just by listening to it. I ...
8
votes
5answers
2k views

Why do harmonics occur when you pluck a string?

When you energise a taut string, the following resonant modes of vibration occur: Plotting on the frequency domain, you can see their corresponding frequencies: But what is the underlying ...
8
votes
2answers
144 views

Pressure standing wave nodes at the end of the open side of a tube

I do not understand why standing sound waves can be formed in a one-side or two-side open tube. Consider a one-side open tube. In particular how does the reflection of the wave at the open end occur? ...
6
votes
2answers
608 views

Is the usually taught solution to forced harmonic motion just a special solution?

Let's say we have a mass on a spring being driven by a forcing function. Given hook's law, $F = -kx$, and a forcing function of $$F(t) = F_0\sin(\omega t) .$$ We can write: $$ m\frac{d^2x}{dt^2} = -...
6
votes
1answer
99 views

Fractional harmonics in musical Instruments

I recently did some Fourier transforms on different audio files containing saxophone or trumpet (John Coltrane/Clifford Brown). I found that with the saxophone, the frequency spectrum occasionally ...
5
votes
3answers
500 views

Physics of a guitar

I understand that when you pluck a guitar string, then a bunch of harmonic frequencies are produced rather than just the frequency of the desired note. If this is true, why does C2 sound so different ...
5
votes
1answer
438 views

Boundary conditions from single-valuedness of spherical wavefunctions

This question is a follow-up to David Bar Moshe's answer to my earlier question on the Aharonov-Bohm effect and flux-quantization. What I forgot was that it is not the wavefunction that must be ...
4
votes
3answers
166 views

Can a standing wave form on a string with both end open

I am fascinated with an idea of an standing wave forming on a string with both end open. If we assume two identical waves coming in of an infinitely long string then for a short period of time, they ...
4
votes
1answer
259 views

Significance of higher harmonics

I am analyzing a noise signal and have identified the fundamental frequency of a tone and it's higher harmonics. Say for example given the signal below, The fundamental frequency has a sound ...
4
votes
1answer
4k views

Why do higher pitches appear to be louder?

It may just be in a few cases, but in the case of a flute, a higher pitch appears to come with a perceived higher volume. Is this simply because you need to put more energy into the flute to get a ...
3
votes
4answers
5k views

Using $\sin()$ or $\cos()$ for computing SHM?

In simple harmonic motion, you can use either the sin or cos form of the equation but my question is which one do you use when and why? I am having a tough time understanding this, so any help would ...
3
votes
3answers
286 views

Why are the closed and open ends of an organ pipe nodes and anti nodes?

Here is a diagram of a wave in an organ pipe you'll find in most physics books Waves in air are longitudinal (not traversal), so what do the curves represent? Why are the open ends always anti ...
3
votes
3answers
2k views

Why does an octave on a piano have the divisions of 8 white keys and 5 black keys?

An octave corresponds to a doubling or halving of the frequency. Each octave on a piano and in classical music score is broken downs into 8 white keys and 5 black keys. Is there a physics explanation ...
3
votes
2answers
27 views

Why is the damping force acting on an oscillating system opposite in direction to velocity and not acceleration?

So far I know that the damping force is a frictional force that opposes motion and so it acts in the opposite direction to velocity . Bit why can't the same be said for acceleration doesn't the ...
3
votes
1answer
96 views

Where exactly is the antinode of an air column with open-closed boundary conditions?

Suppose that I have an air column with closed-open boundary condition. The air pressure at the open end of the tube is constrained to match the atmospheric pressure of the surrounding air. Therefore,...
2
votes
1answer
824 views

Where are the harmonics in the radio spectrum?

When I strike a string on my guitar and look at the audio spectrum, I can see the fundamental frequency as a large peak. I can also see the harmonic frequencies as a train of little peaks at ...
2
votes
3answers
46 views

Harmonic frequencies of a guitar string

I'm studying harmonic frequency at the moment but I'm just a bit confused about something. How are more than one different frequencies able to be produced from plucking a guitar string (fundamental ...
2
votes
1answer
174 views

How to find the first-harmonic frequency from the frequency spectrum of a recording of this harmonic being struck on a guitar?

Just as the title implies, I was trying to find the fundamental frequency of a guitar string at various tensions as a part of an experiment to find its Young's modulus. In the experiment, I connected ...
2
votes
1answer
2k views

Harmonics in an open organ pipe

How to solve the following question? An open organ pipe has two adjacent natural frequencies of 500 and 600 Hz. Assume the speed of sound in the air 340m/s. The length of the organ pipe is? What ...
2
votes
1answer
70 views

In which-pattern does the individual-particles move in a longitudinal wave?

Transverse waves, such as upper-surface of pond-water, or in shaking-rope; the Transverse-Wave can be easily understood and drawn (for different times such as at t second, t + 0.25 second, t+0.5 ...
2
votes
1answer
128 views

planewave Ansatz for modelling phonon dispersion in crystals

From Ashcroft's "Solid State Physics", for one-dimensional monatomic Bravais lattice, the equations of motion of ions are: \begin{equation} M\ddot u(na)=-K[2u(na)-u([n-1]a)-u([n+1]a)] \end{equation} ...
2
votes
3answers
18k views

When are Maximum Velocity and Acceleration acheived in Simple Harmonic Motion?

Im trying to get my head around SMH out of curiosity because it seems simple yet I'm not getting the concept behind some ideas. For a SMH equation : $$ x=a \sin(\omega t+\phi) $$ Under what ...
2
votes
1answer
95 views

Frequency of an open air column

Given only the length of an organ pipe to be $2.14 m$, is it possible to find what frequency it vibrates at? If I use the equation $f=\frac{v}{\lambda}$, does the $v$ apply to the speed of sound in ...
2
votes
2answers
386 views

How can Hilbert spaces be used to study the harmonics of vibrating strings?

The overtones of a vibrating string. These are eigenfunctions of an associated Sturm–Liouville problem. The eigenvalues 1,1/2,1/3,… form the (musical) harmonic series. How can Hilbert spaces be ...
2
votes
0answers
73 views

How can I prove that antinodes are present at both open ends of organ pipe mathematically? [on hold]

I know that for anti node to be formed the magnitude of displacement should be maximum at there. For standing waves in an organ pipe, the boundary conditions are such that anti nodes are formed at ...
2
votes
0answers
147 views

What is the mechanism of subharmonic oscillations?

It's clear to me from linear systems theory that energy manifested within a fundamental mode of resonance can saturate with the excess energy spilling over into harmonic frequencies greater than the ...
1
vote
3answers
176 views

Simple harmonic motion versus oscillations

I want to see whether certain oscillations in my daily life, such as the oscillation of violin strings when plucked, are simple harmonic motion or not. Can we identify whether an oscillation is simple ...
1
vote
1answer
80 views

Picking a guitar string of fixed length to get any nth harmonic, is it possible?

In physics textbook, we can calculate the nth harmonic of a vibrating string of a fixed length. How can we do this in a real guitar? For example, if I just pick a single open string, how can I get ...
1
vote
2answers
237 views

It seems that the harmonic (integer multiple) overtones of a sound usually all have the same phase. Is this true, and if so why?

And if you were to give each of them different phases, would the sound start to sound "off", or would it sound the same? All the same frequencies would be present, which makes me think it might sound ...
1
vote
2answers
781 views

A foundational question about harmonic motion : 2 pipes with different length and frequencies [closed]

How to solve the following question? A pipe open only at one end has a fundamental frequency of 256Hz. A second pipe, initially identical to the first pipe, is shortened by cutting off a portion ...
1
vote
1answer
25 views

What does it mean for a particle to be subjected to 'more than one' simple harmonic motion? [closed]

Also what can we say now about its --> Resulting Energy? -> Resulting Amplitude? -> Maximum Velocity? Please help as I am not able to understand the process going on. I also tried to represent this ...
1
vote
1answer
132 views

Harmonics and the frequencies

Let's say we had a pipe which was closed on one side and open on the other. We can find the wavelength for the first harmonic. To find the second harmonic we just add one more antinode and find a new ...
1
vote
1answer
612 views

Open Ended/ Close Ended instruments?

Close ended instruments have twice the wavelength, because the wave must travel twice the distance to repeat itself. Why must a wave reach a lower density medium (air in this case) to repeat? When ...
1
vote
0answers
30 views

Low Frequency Wind Chimes

I'm building a public sound sculpture made of tuned aluminum pipes -- think wind chimes that people can play. I want to include lower frequency chimes in the sculpture, but the fundamental frequency ...
1
vote
1answer
106 views

What is the relationship between harmonic motion and the harmonics of a wave?

I learned about harmonic motion and harmonic oscillators a long time ago in physics, but I can't remember what the relationship between that and and the definition of harmonic in a wave. A harmonic ...
1
vote
0answers
47 views

What is the exact renormalization regularization for divergent harmonic serise?

given the harmonic series $$ \sum_{n=0}^{\infty}\frac{1}{n+a} $$ what is the correct option for the regularization ? a) $ \sum_{n=0}^{\infty}\frac{1}{n+a}= -\Psi (a) $ Digamma function b) $ \...
1
vote
1answer
259 views

Woodwind instruments overtones [duplicate]

When playing woodwind instruments, e.g., flute, if one blows harder, the sound will be one octave higher. Even harder gives even higher overtones. Does anyone know why?
0
votes
3answers
169 views

Fluid filled harmonic oscillator

A vessel (preferably circular) filled with water is accelerating unidirectionally such that the level of water is higher on one end than the other. What I want to know is that if the vessel is ...
0
votes
1answer
12k views

Finding phase angle of simple harmonic motion [closed]

A sinusoidal oscillator has : $$x=x_{max} \cos(\omega t - \varphi )$$ Period is 2, initial displacement is 100mm initial velocity is 200mm/s What is the phase angle assuming $-\pi < \varphi < ...
0
votes
1answer
38 views

Which experiments of harmonic generation at low frequencies preceded Franken's SHG?

In The Principles of Nonlinear Optics by Shen, he says that the generation of harmonics at low frequencies were long-known before Franken did SHG in the optical range. Franken's idea was simple. ...
0
votes
1answer
24 views

Why is second harmonic Intensity periodic in coherent length?

Solving for the intensity of second harmonic generation we get that intensity is $sinc^2(\pi/2*L/L_{coherent})$. How is calculated that the intensity is periodic in L_{coherent} (coherent length, L ...
0
votes
3answers
5k views

Young's Modulus and Vibrating String Harmonics

I was wondering how Young's Modulus effects the resonant harmonics of a vibrating (string instrument) string. I know that the string's fundamental frequency is $$\frac{1}2 \times \text{Length} \times \...
0
votes
1answer
980 views

What are overtones and how do they relate to harmonics?

Problem 43. Two organ pipes, a pipe of fundamental frequency 440 Hz, closed at one end, and a pipe of fundamental frequency 660 Hz, open at both ends, produce overtones. Which choice below correctly ...
0
votes
0answers
52 views

How was the “vibrating string” studied?

The vibrating string is used to derive a lot of theory regarding strings, such as the theory about harmonics. However, since the string movement and specifically the phenomenon of harmonics seems ...
0
votes
0answers
31 views

How can I determine if a peak in a spectrofluorometer's spectrum is erroneous?

Let me give you the specific scenario since I'm really not sure which factors are relevant or not: Our lab made our own upconversion nanoparticles (UCNP) following a popular paper on the subject. ...
0
votes
0answers
39 views

Resonance and harmonics: change in phase difference, and force due to a non uniform magnetic field

I am doing an experiment (at school) on oscillating wires and I am following a lab script. Along the way, it asks some questions that I am supposed to answer. The only problem with this is that we ...
0
votes
0answers
23 views

find cylindrical multipole coefficients

How does one find the coefficients to the cylindrical multipole expansion? I have the harmonic function $\omega = \dfrac{f(\theta)}{\sqrt{r}}$ where $f(\theta)$ is function with a period of $2\pi$ ...
0
votes
0answers
101 views

Second harmonic generation - how does SHG spectrum and pulse differ from the fundamental?

I'm trying to learn about second harmonic generation (SHG) in nonlinear optics but can't seem to find a conclusive answer to the following questions. 1) If generating SHG using a pulsed laser source, ...
0
votes
0answers
155 views

Which is has the highest (greatest) sound intensity - Sine, Square or Sawtooth waveform?

From this, http://electronics.stackexchange.com/questions/42904/square-wave-sine-wave-is-more-audible I now understand that a Square soundwave will be perceived louder than that of a Sine sound wave ...