What is Sound pressure: Definition and 27 Discussions

Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa).

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  1. Marcogoodie

    Sound absorption/Acoustuic attenuation coefficeint (α(ω)) of PVC foam?

    I am currently doing a physics experiment to find the frequency-dependent attenuation coefficient (α(ω) )of pvc foam, are there any verified/reliable sources that show the attenuation coefficient α(ω) of pvc foam or materials in general? Best I found is this...
  2. N

    I Sound pressure and inverse distance law

    Hello, I am confused as to how to think about sound pressure and the distance from a sound source. Let's assume that a sound wave is omnidirectional and propagating away from a source in a sphere. We have the following two equations: Pressure = Force/Area Intensity = Power/Area Many texts...
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  5. Jese Reyes

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    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...
  6. PSuran

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    Hello, I have a question that I've been struggling to find an answer to / understand. Probably because my understanding of physics is quite limited :) Before I ask the question, these are the things I take as facts, so please correct me if something is wrong: 1. A speaker in half space...
  7. Rorshach

    Tympani in a concert hall: calculating Sound Pressure Level (SPL) and delay

    Homework Statement Hello. I have a problem, which is as follows: A seat in a concert hall is 84 ft from the tympani. The tympanist strikesa single note. The sound pressure level of the direct sound of the note at the seat is measured to be 55 dB. The first reflection from the nearest sidewall...
  8. lukasleopold

    Estimating sound pressure (in an MRI scanner)

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  9. Y

    Sound Pressure in Partial Vacuum

    Is there a good description or formula regarding how the sound pressure from a constant source depends upon ambient pressure? That is, if I were to conduct an experiment where I put a source and a microphone in a container, and then change the pressure in that container with a pump, assuming...
  10. R

    Units of sound pressure level, example: 120 dB re 20 μPa

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  11. A

    How to find the sound power in a collision?

    How would you go about calculating the sound power and sound pressure given the pressure (as in collisions [force/area]) of the collision, kinetic energy in the collision, velocities of both objects, densities and masses. Is this possible? Is the pressure of the collision equal to the sound...
  12. L

    Calculating Sound Pressure Level As Distance Changes

    Homework Statement The sound pressure level is 80db at a distance of 30 meters. What is the dBSPL at 60 meters? Homework Equations My book has provided me the following formula: dBSPL = dBr-20log(di/dr) - but it has not explained what "di" and "dr" are.The Attempt at a Solution I've been...
  13. R

    Sound pressure level at vacuum cleaner and earphones

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  14. B

    Why does sound pressure vary with 1/r?

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  15. J

    Sound Pressure inside the cabin

    Hello, I am trying to measure the sound pressure inside a cabin. I placed 2 microphones to measure it using octave band. For each frequency i have two sound pressures ..is it possible to take the average of them ? for example add the 2 sound pressure for the 2 microphones and divide...
  16. C

    Is there a formula for calculating SPL?

    Hi. Is there a formula for calculating SPL? The information I have is Frequency of pitch, dB level of pitch and 0dB as 20uPa. TIA
  17. R

    Overall Sound Pressure Level between two Frequencies

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  18. B

    Sound waves and sound pressure

    Homework Statement Consider a sound wave in air of density 1.2 kg/m3. The displacement wave has the form s(x,t)=smaxcos(kx-\omegat) where k=8.79rad/m, \omega=3021.6 rad/s and smax=2.51 x 10-7m. Calculate the sound pressure \DeltaP(x,t) of this wave at x=0.282m and t=0.00137s. Answer in units...
  19. S

    Calculate sound pressure inside a cavity

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  20. L

    Why does particle displacement A increase sound pressure?

    pressure=p(x,t)=BkAsin(kx-ωt) http://www.physics.unomaha.edu/Sowell/phys2120/Lectures/Sound/Sound.pdf Surely, when loudness-intensity-pressure increases, so does the maximum displacement A of the speaker. Wrong thread title. My question is: Why increasing the maximum molecule...
  21. T

    Lowering Sound Pressure: Techniques and Considerations

    How to lower sound pressure (i.e. the volume of a sound)?
  22. Y

    Determing Sound Pressure Levels (SPL)

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  23. L

    What Is the Optimal Position for an Acoustic Barrier to Reduce Road Noise?

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  24. N

    Validity of a Formula for Superposition of Coherent Sound Waves

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  25. H

    Sound pressure level and sound intensity level

    Hi all. A very simple question: what is the difference between sound pressure level and sound intensity level? It seems to me that sound presssure level also measure the "energy" since it is p^2, which shall be related to energy... If it is so, it seems that sound pressure level shall be the...
  26. S

    Sound Pressure Calculations for a Baby and Parents

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  27. S

    Sound pressure level magnitude question.

    Hey all, I've got an audio related question for you guys/gals: I understand the logarithmic relationship to SPL, but would someone help me out with a simple question and post a formula as to how you arrive at an answer? Assuming a start value of 150 decibels, what pressure level would...
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