Acoustic Definition and 174 Threads

TL;DR Summary: The theory for ears are well developed so far. Is there a more authorative book or paper? Where can I find a good book or a paper?

Question: My Answer: Is it correct? Thank you

The standard derivation in obtaining a single wave equation involves making use of the heat equation with a Taylor expansion of the equation of state, then differentiating this equation and the continuity equation with respect to time, and combining with the divergence of the NS equation...

So the video I'm referring to is the second in this webpage. Around time stamp 3:55 mr Wolfgang, the demonstrator, says that the little balls settle down at the high-pressure areas, which are signaled by the bright bands in the Schlieren image. We understand this by noticing that the area near...

Hi all I have acoustic noise level value in dB vs 1 dyne/sq cm e.g. -10 db vs 1 dyne / sq cm. I need to convert it into dB ref 1upa unit. How i will convert it? Thanks & Regards

Hi, I am trying to get the transfer function from a wall between rooms. From one side I have the force of a hammer as an input ,and in the other side of the wall (next room) I have an accelerometer. Is it possible to get the TF without know the damping, stiffness and mass of the wall partition...

Question: Answer: I don't understand about a and c. I just tried to solve b but my answer is still lacking for part b. Can anyone guide me about how to solve these problems and what I did wrong in part b.

Hi all If we have an acoustic transducer and values of its two parameters are known, i.e conductance and capacitance, is it possible to calculate impedance using these two parameters? Thanks

I have read about doppler effect in acoustics so i searched for the relation ship between wavelength of wave produced by linear movement of body and its momentum along with other dependent variables such as density of fluid (leaving acoustics for a second) and temperature but souldn't find a...

I found there is kind of solution in Pointon's book: An Introduction to Statistical Physics for Students. But I don't know how to find intensity by using frequency.

Good day. We know how simple objects, such as 1D wires behave when a simple harmonic wave travels along a wire, or two wires knotted togethe.We also know what happens if you excite a circular thin disc with a single frequency. Are there some material I can read on, that considers the effect...

There are some mathematical models (eg Delany-Bazley) to calculate impedance of porous materials and these formulas give complex impedance values as a result. But I could not find any model to be used for seafloor (underwater ground modeling) or I don't know if existing models may be used. I...

I have calculated the wave length of a 36 kHz acoustic wave in 20 °C water to be around 41.16mm. Suppose I have a transducer that produces a 36 kHz acoustic wave and a small water container with a length of 41.6 mm. How will the standing acoustic wave look like, which is produced by the...

Hi all I am trying to calculate Source Level 'SL' of a underwater acoustic Cylindrical Array with multiple Transducers. The array has 03 Rings with 32 transducers in each Ring. The spacing between each ring is around 0.18m whereas Dia of each Ring is about 1m. Each transducer is being driven...

I was in Urbino a walled city in the Marche region of Italy. At the foot of Duke's palace we found an elliptical wall. It has been mentioned that the guards were once placed at the ends of the wall. In fact the city is located on top of a mountain, the guards had to watch over the whole valley...

I was reading a pdf on acoustic grating for my practicals when I saw that the grating element of an acoustic grating is equal to the wavelength of the sound wave. I also checked a few other sources and got the same. I do not understand why. I know that for an acoustic wave, the standing wave...

For example: https://www.laserfocusworld.com/test-measurement/research/article/16566273/scientists-develop-saseran-acoustic-laserthat-produces-terahertz-sound-waves Can these devices produce ionizing radiation? I understand ultrasound traditionally does not produce ionizing radiation, but I am...

My neighbor has two AC condensers are driving me insane. I took measurements of the units, and they were between 33.5db - 47.9db at 80HZ. About 3 feet away is a cinderblock privacy fence between us. It is about 10 feet tall. His home is on an elevation about 4 feet higher than mine (so the...

I am trying to come up with a design for a device that can generate very high and very brief waves of pressure directed at a 1 mm diameter target (shown as "E" in "Diagram.PNG") housed in a steel support structure "D". The idea is to accelerate hammer "A" towards anvil "B" in a vacuum tube. The...

In most standard exposition of (the mean-field theory of) charge density wave (CDW), phase and amplitude fluctuations are introduced as the collective excitations. Kohn anomaly in the acoustic phonon dispersion is also mentioned as temperature goes from the above till the CDW transition...

https://www.upi.com/Science_News/2019/07/30/Mathematical-model-identifies-acoustic-signal-preceding-seismic-shake/4431564489814/

Hi, I'm trying to model the transmission loss and SNR of an acoustic signal underwater. I'm using this expression to modelize the transmitted signal: y = sqrt(P)*exp(1i*2*fr*pi*t)' where P is the transmission power in watts, fr is the transmission frequency and t is the acquisition time. The...

Summary: I have been trying to understand the abstract and introduction to the paper https://arxiv.org/pdf/astro-ph/0501171.pdf DETECTION OF THE BARYON ACOUSTIC PEAK IN THE LARGE-SCALE CORRELATION FUNCTION OF SDSS LUMINOUS RED GALAXIES. I made an effort to find in the paper the answers to...

Hey all, I am doing some work to brush up my acoustics and one of the problems I came across this goes like this (translated, so sorry for potential grammar mistakes although I'll do my best to avoid them): A singer exhales 0.1 Litre Air per second. The 'overpressure' (pressure difference, so...

Hi everyone. Firstly, I'm not a physicist, so relatively "intuitive" explanations would be greatly appreciated :) I'm confused by the following: Let's say we have a partition / wall, which resonates at a specific natural frequency. If the resonance is relatively high Q (low damping), then...

Acoustic barrier fence is an excellent way to add sound absorption to an industrial or architectural environment to reduce harsh reflections from hard reflective surfaces, thereby lowering noise levels

I am trying to understand the physics of resonance phenomenon. One can find the resonant modes of a water filled spherical cavity either analytically or by using the FEM eigenvalue analysis (K-ω2n M = 0, with K and M being the usual stiffness ans mass matrices in FEM). For the later, we usually...

Dear all, For my students, I'm currently trying out some experiments they can do to simulate acoustic processes. One of the topics that we will be discussing is that of standing waves. Although I have never done it before--I come from a completely different background--I want to create...

Hi all I am in search of a Power Amplifier (preferably Solid state pulsed amplifier ) which is able to output around 340 Vrms across 25 ohm impedance load (acoustic transducer operating at approx 4.5 KW) in pulsed mode with duty cycle less than 1%, maximum pulse length of 5 ms and operating...

Hi all, I have some problems to understand how to calculate the transmission loss at long distance, which model do I have to use? I was looking into the energy flux model (Weston model), but I didn't understand at what range I should switch from "mode stripping" to "single mode". I am working...

Homework Statement Hello, I have a problem with a quote from a textbook I am currently reading, and it is not strictly a homework problem. It is a part of the book in which authors explain mechanism of sound amplification in human ear, specifically by resonance in ear canal and mechanical...

Hi, I wonder is it possible to trap electrons in vacuum using acoustic waves as it is possible to trap them using electromagnetic waves? imagine a vacuum tank and electrons injected say from a thermionic emission (electron gun) and having one or two transducers set apart to produce satnding...

Homework Statement Spaker located at 90 feet from a auditorium chair. The sound pressure level at the chair is 70 dB. The first reflection from the roof takes 200ms to get to the chair. What distance does the first reflection travel to get to the chair if the room temperature is 303.15 K? What...

Please can someone explain me how high levels of ultrasound can be created in Air? Should we consider the Ultrasound or we should concentrate only on sound level in Air as frequency ultrasound have no effect on sound level?

Acoustic impedance of material is defined by density multiply by the velocity of waves within the base material. My question is if i have a tubular or hollow part with a base material, does this count as a reduction of density compared to the base material of the tube or hollow part. Would the...

Note: this is a re-post from the physics area because this thread is probably more appropriate for this content. There is a lot of rather contradictory information present on the biological effects of acoustic weapons with a bevy of scientific articles claiming that they cause harm to...

I do apologize if this is considered against the general discussion rules. I'd really like to get the opinion of individuals of an intellectual nature. I remember a recent discussion with a few family members on the topic of building infrastructure (roads) that generates electricity utilizing...

Dear all, I have a question related to acoustic propagation in isotropic lossy media, more specifically generation of Lamb waves at fluid-solid interfaces. There goes the question: I am trying to obtain the Lamb wave velocity and attenuation dispersion curves of viscoelastic materials...

Hi Physics, I have an idea but before i start. I must know am I right. Is it possible? We have a small room with two objects. The first object is a producer of sound waves out of the human hearing range. This object sends ultra sound waves to the second object. The second object start to...

Hello~ Is there anyone good to make a simple acoustic receiver,just like using an IC to connect several capacitors? Someone pose a picture just as follow.And said that is to make a small amplifier with a single chip and the making of mono loudspeaker and double channel loudspeaker are in this...

I'm trying to do a simple calculation, but there must be something wrong. The wavelength ##\lambda_1## corresponding to first acoustic peak of the CMB is related to the sound horizon at last scattering, ##d_{hs}##, by : ## \lambda_1 = 2d_{hs} ## (see for instance slide 14 on Wayne Hu PDF...

Hello everyone, I want to calculate or rather simulate a particle movement by influence of a ultrasonic wave. I have read many times that I have to use the acoustic radiation force for calculating the movement of a particle but not why? At first I calculated the particle movement only with...

Is it true that the higher the frequency of sound, the narrower the wave will be?

What is the formula to calculate acoustic absorption in water? particularly sound in the ultrasonic range.

Homework Statement An interface is formed between a block of aluminium (density = ##2.70 \times 10^3 kg/m^3##, speed of sound =##6.40 \times 10^3m/s##) and a block of copper (density = ##8.96 \times 10^3 kg/m^3##, speed of sound =##4.76 \times 10^3m/s##). Longitudinal waves traveling through...

Hello, I have a practical problem, I'd like to find the "best" spot to hear sounds in a valley (forgive me if "acoustic point" isn't an appropriate term, I just couldn't come up with anything better and scrolling an acoustics text didn't help), or at least a non-blind spot (one which instead...

Baryon acoustic oscillations acoustic peaks in cosmic microwave background anisotropies provides evidence for cold dark matter but is there any sort of prediction as to the specific properties of this dark matter? predictions as to the mass of this dark matter, total mass, and mass of the...

I don't understand the difference between the Jeans Mass and the fundamental mode. Both are reaching till the horizon but according to me is the Jeans mass not oscillating. So what is the relation between a Jeans mass and the fundamental mode of the acoustic waves?

i'm doing an experiment to study the effect of sound waves on fire and smoke and would like to know how can i produce sound waves with frequencies varying from 0-200 hz

Hi, I was wondering on how to implement a sinewave oscillator with a variabke frequency from 20hz to 20khz. What types of circuits are there to do this and what sort of parameters would affect the frequency range? Thanks