What is Acoustic: Definition and 173 Discussions

Acoustic music is music that solely or primarily uses instruments that produce sound through acoustic means, as opposed to electric or electronic means. While all music was once acoustic, the retronym "acoustic music" appeared after the advent of electric instruments, such as the electric guitar, electric violin, electric organ and synthesizer. Acoustic string instrumentations had long been a subset of popular music, particularly in folk. It stood in contrast to various other types of music in various eras, including big band music in the pre-rock era, and electric music in the rock era.
Music reviewer Craig Conley suggests, "When music is labeled acoustic, unplugged, or unwired, the assumption seems to be that other types of music are cluttered by technology and overproduction and therefore aren't as pure".

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  1. andrewkirk

    Can we hear a supersonic plane?

    A very clever first-year physics student I know, who had just been learning about the Doppler effect, asked me a question. If a plane were flying a straight trajectory at Mach 2, playing a song on its speakers very loudly, and an observer with incredibly sensitive recording equipment were to...
  2. andrewkirk

    Acoustic 'beats' from mismatched musical frequencies - Comments

    andrewkirk submitted a new PF Insights post Acoustic 'beats' from mismatched musical frequencies Continue reading the Original PF Insights Post.
  3. S

    Doppler effect with moving medium but no relative motion

    I would like to be sure about one case of the use of Doppler effect with sound waves. If the medium (in the case of sound air) is moving, but there is no relative motion between the observer and the source there is no Doppler effect at all. (And the absence of relative motion is...
  4. E

    Ready to try acoustic levitation at home? What equipment do I need?

    Hello everyone, I would like to start playing around with acoustic levitation. Apologies if this is the wrong sub-forum... I psoted in General, as I am not sure where the best place would be for this. My question: What equipment would be needed to start a simple acoustic levitation? I have no...
  5. S

    Finding the speed to receive sound constantly

    Homework Statement A source emits a very brief sound signal. A receiver ##A## moves along the ##x## axis with a varying velocity such that it receives constantly the echo from the reflecting wall. Find ##v_A## as a function of the position ##x##, knowing the distance ##D## and the speed of...
  6. S

    Device that detect waves in a frequency range and beats

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  7. S

    Beats: frequency of resulting wave vs. beats frequency

    The beats frequency heard from the interference of two sound waves with frequencies ##f_1## and ##f_2## is $$\nu=|f_1-f_2|$$ Nevertheless the frequency of the resulting wave is not ##\nu## but the mean value of the two frequencies $$f_{resulting}=\frac{f_1+f_2}{2}$$ As far as I understood...
  8. C

    What is the Acoustic Impedance of Wool?

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  9. chikou24i

    A Acoustic and optical branches in phonons dispersion curves

    What is the physical meaning of acoustic and optical branches in phonons dispersion curves ?
  10. I

    Calculation of peak acoustic intensity (in water)

    If we know the max. pressure (p) is 2.5 MPa and T = 20 C. Peak intensity, I = p^2 / rho * c where rho = density of water: 0.9982E03 kg/m^3 and c = speed of sound in water: 1482.3 m/s at 20 C I = (2.5E06 [Pa])^2 / 1.4796E06 [kg/m^2/s] = 4.2241E06 W/m^2 Is this correct?
  11. L

    A Difference between an optical and an acoustic phonon

    Hello friends. My question consists two parts, 1-What is the difference between an optical and an acoustic phonon? 1-What are the conditions by which we can decide the type of phonon i.e optical or acoustic phonon ? Hope to get the reply soon.
  12. I

    Acoustic impedance water surface in partially filled tank

    Hello guys, Consider a partially filled tank with water where the acoustic field can be described by the Helmholtz equation. The boundary condition at the water surface would be \frac{∂p}{∂\vec{n}} = -j\rho_0\omega\frac{p}{Z} where Z is the impedance of the water surface. What would be...
  13. S

    Understanding a sound spectrum analyzer output

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  14. P

    Acoustic horns and impedance matching

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  15. I

    What exactly is a complex acoustic pressure?

    I have an impedance tube and it gives me the magnitude (dB) and phase (phase) of a signaa. So does that mean the complex pressure at that point is simply the [Magnitude] +i[Phase Value]? Does I need to change the units at all?
  16. can12345

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    Hello everyone; My question is regarding to velocity effect on transducer diaphragm. When fluid flow is acting to differential pressure transducer's diaphragm, the diaphragm is osculating(vibrating) and there will be fluid flow which is transverse(opposite flow,back flow) to normal fluid flow...
  17. T

    Gas Dynamic to Acoustic wave equation

    Homework Statement Derive from the formulas ##\frac{D^\pm}{Dt}(u \pm F) = 0## where ##\frac{D^\pm}{Dt} = \frac{\partial}{dt} + ( u \pm c) \frac{\partial}{\partial x}## the one-dimensional wave equation in the acoustical limit. \begin{cases} u << c\\ c \approx c0 = const\\ F =...
  18. L

    Acoustic phonon lifetime is larger than optical phonon?

    for example, in GaAs, the LA phonon lifetime can be ~850 ns, while LO phonon lifetime is only about 5 ps. Why such huge difference occurs? Thanks!
  19. wolram

    How can BAO and SN constraints be compared for measuring dark energy?

    How do BAO help us measure dark energy? thank you for all the help PF members give in the cosmology forum.
  20. J

    Classical Looking for an acoustic physics book

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  21. Loran Pittman

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  22. J

    Acoustic Impedance - Ultrasound Propagation in Tissue

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  23. Saumya Kar

    Difference between acoustic pressure and fluid pressure

    While the sound waves travel in a medium, let's say a fluid, what is the difference between fluid pressure and acoustic pressure ? Are these entities same?
  24. R

    What is the relationship between particle size and acoustic radiation force?

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  25. C

    How can I create affordable soundproofing for my apartment bedroom?

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  26. D

    Baryon acoustic oscillations and sound horizon

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  27. R

    Why Do We Use the Complex Conjugate of Velocity to Calculate Acoustic Intensity?

    Hello All, I would like to know why do we multiply the complex conjugate of velocity (not just the velocity) with the complex pressure to obtain the complex acoustic intensity. Could someone please help me with this? Regards, Radel...
  28. Z

    What is the lower limit of frequency range of acoustic phonon modes?

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  29. bartekac

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  30. M

    Acoustic pressure & particle velocity phase - plane vs spherical waves

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  31. L

    PDE (wave equation) used to find acoustic pressure in a a pipe

    Homework Statement Assume that the wavelength of acoustic waves in an organ pipe is long relative to the width of the pipe so that the acoustic waves are one-dimensional (they travel only lengthwise in the pipe). Therefore, the equation governing the pressure in the wave is: ∂2p/∂t2-c2*∂2p/∂x2...
  32. J

    Baryonic acoustic oscillations and density perturbations

    Hi, I am just trying to understand the connection between these two things. As far as I understand it: BAO - Before decoupling the baryons were in thermal equilibrium with photons and as a result this gave rise to a pressure force. But given in regions of high dark matter density baryons are...
  33. F

    Acoustic Wave Velocities in Brillouin Zone

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  34. A

    Acoustic standing waves with an open far end

    My textbook says I'm confused by this, because isn't a standing wave caused by reflection of the waves once it has hit the end of the tube and reflects backwards. How can sound waves be reflected from the open air? Thank you for taking the time to answer. :)
  35. E

    Acoustic levitation shape question (Japanese scientists link)

    http://sploid.gizmodo.com/amazing-scientists-make-things-fly-around-in-space-usi-1492880964 I wanted to ask is there a specific reason for the completely horizontal X shape of the levitated particles. If we already have such precise control over the standing waves, couldn't it be possible...
  36. T

    Acoustic Focusing of particles on a large scale

    Greetings PFers, I'm working on a project where I need to focus powdered that is being blown through a tube. I would like to discuss the option of using acoustic focusing to guide the particles to the axis of the tube to prevent the particles from contacting the tube inside diameter. There...
  37. A

    Optical and acoustic modes

    Basically phonons in crystals can either be acoustic or optical according to my book. But then it stresses that a necessary condition for this to hold is that the crystal has more than atom per primitive basis. The optical modes are then when neighbouring atoms oscillate out of phase (i.e. no...
  38. F

    Acoustic Observatory - Low-Cost

    Acoustic Observatory -- Low-Cost I have built what I call an Atmospheric Acoustic Observatory. It could also be thought of as a high-resolution barometer. There's a write-up on it at http://www.comfortlight.com/baro.htm. It is simple in principle, and it cost only about $50 for the main...
  39. F

    Acoustic Observatory - Low-Cost

    Acoustic Observatory -- Low-Cost Check out my Acoustic Observatory It uses well-known and obvious principles of operation to "see" thunder at great distances. It cost about $50 to build, including the red laser diode -- but not including the front surface mirror which has been lying around my...
  40. H

    Are Faraday waves acoustic waves?

    Hi, I am confusing if capillary-gravity waves (Faraday waves) belong to a type of acoustic waves stricto sensu? What's the difference between Faraday standing waves and acoustic standing waves (interference) at the the air-liquid interface. Thanks harmonyU
  41. T

    Calculating Acoustic Pressure: Threshold of Pain for the Ear

    Homework Statement Atmospheric pressure is 101 kPa. Compute the acoustic pressure that corresponds to the threshold of pain for the ear. What percentage of atmospheric pressure is this? Homework Equations L=20log(P/Po) Po is a constant = 2x 10-5 threshold of pain for the...
  42. M

    Acoustic Wave & CMB: Exploring Anisotropy & 7 Peaks

    Dear all, many people refer to the CMB anisotropy picture by WMAP or Plack and call it acoustic waves. I thought there is the anisotropy of the CMB radiation plotted, what exactly can I imagine to be the acoustic wave of it? Secondly, what exactly is plotted n the famous plot where the...
  43. T

    Acoustic Resonance Chamber Design- Wine glass shattering

    Greetings PFers, I'm designing a demonstration unit for use in grade schools demonstrating the principle of resonance upon wine glasses (shattering them). I intend to put a wine glass into an acrylic chamber of some geometry, hand the student a microphone and see if they can generate the...
  44. atyy

    Acoustic communication impossible in even-D

    Arnold, an in interview with Lui in Notices of the AMS, Volume 44, no 4, p432 says: "It is a far-reaching generalization of the well-known fact of the impossibility of acoustic communication in the even-dimensional spaces (for instance, in the “plane” world), while in our three-dimensional...
  45. J

    Acoustic Communiaction References

    I'm doing a research paper about electronic wireless communication using sound. I've got a few reference regarding its use in underwater networks, networking within a body in a medical context, and one regarding communicating information through a steel wall (such as a sealed pressure vessel)...
  46. iVenky

    Acoustic impedance- pressure and velocity

    I find that the acoustic impedance is given by Z= Pressure/ Velocity I read that the acoustic impedance of a plane propagating wave is given by Z = ρ0c. What is ρ0 and c? Thanks a lot
  47. P

    Acoustic Length in Pipe/Tube Explained - Physics Lab

    What is acoustic length in a pipe/tube? On a physics lab, the lab write up mentions it but it doesn't explain what it is. I know it's give by L = λ/4 and higher ones will be odd multiples of the first one. But what does this actually mean and what is it for? I looked it up but couldn't find any...
  48. J

    Separating Acoustic Waves from Background Reflections

    I'm trying to classify materials based on the reflected acoustic wave they produce. One transducer sends out an ultrasonic pulse to the material of interest and another transducer picks up the reflected waveform. Some of the wave is transmitted thru the material and reflected off of the...
  49. R

    Can a Laser and Reflective Material Create a High-Frequency Microphone?

    Greetings, I've been looking for a way to create a microphone capable of picking up high frequencies (up to about 100kHz). Electrets don't tend to go that high and piezo crystals even detuned will only give a limited band. I had the idea of bouncing a laser off a sheet of reflective...
  50. T

    Understanding the Effects of Acoustic Impedance on Animal Vocalizations

    I am working on an animal vocalization study and I need a clarification about acoustic impedance. All of the sources I have gone to are a bit too technical for me, so if you would be so kind to answer my question I would be very grateful! My question is this: What happens to a sound in high...
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