Questions tagged [acoustics]

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. Applications of acoustics are for instance the audio and noise control industries.

When to Use this Tag

Use when asking questions about the generation, propagation, or absorption of sound. Additionally, the tag can be used for questions regarding the working principles and characteristics of electroacoustic transducers.

Introduction

Acoustic waves may exist in any elastic medium which is capable of experiencing compression and rarefaction. This is manifestly true in the case of liquids and gases. However even solids, which are often taken to be perfectly incompressible, can sustain small oscillations of their constituent atoms about some mean position which enables wave propagation throughout the material. Generally speaking, the higher the compressibility of a material, the lower its speed of sound.

Equations of Motion

Wave motion in a variety of different contexts is governed by the classical acoustic wave equation. This linear partial differential equation has been derived on the hypothesis that the perturbation quantity is small relative to a mean value. Generalizations to this equation may be obtained which incorporate more exotic physical effects such as dispersion, convection of acoustic energy, and nonlinear wave steepening.

Prerequisites for Studying Acoustics

Phys: Some exposure to rigid body dynamics and fluid mechanics

Math: Ordinary Differential Equations (ODEs), Partial Differential Equations (PDEs)

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How to deal with the difference in sound when the audience comes in

For mixing in a small church, with cheap equipment, we have the following problem. When we set up all equipment and do a sound-check, all levels are good and the sound is just very good. When the concert starts, and the audience comes in, levels…
Peter Smit
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Fixing acoustics in a glorified hallway

We have a small radio studio that is essentially in a hallway. When on air, you can definitely hear the room coming through the mics. It sounds like there is a lot of standing wave. Our budget is small, but we can get money to fix it if I can come…
Brad
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Acoustics exercise

I have been asked to solve this exercise. An environment of $V=1500$ $m^3$, it is considered a reverberated field acoustic pressure level of $70$ $dB$ when an acoustic source of $80$ $dB$ is activated. Compute the total absorption (in $m^2$) in…
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How does our brain detect the direction of sound?

We are able to detect the direction of sound because of our brain's capbility to measures the time lag and amplitude difference between the sound that reaches our ears. However the sound produced by a source 10 meters directly in front of us and…
CODESIGN
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Why do I hear less bass in the middle of the room, and can I do anything about it?

I've recently purchased a pair of monitor speakers in order to build myself a better critical listening environment. I've tried setting them up near one wall in a small room off of my living room, whose dimensions are about 8'x7', and which is about…
Warrior Bob
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Acoustics and Auralex?

I'm about to make a tremendous rework of the acoustics in my studio, and a fix for the 129Hz standing rez-wave that haunts it. Right now I'm looking at Auralex Wedges, considering possibly 4" wedges at the hotspots and 2" elsewhere, with bass-traps…
Christian van Caine
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Are styrofoam skyline diffusers efficient as wood?

I'm making my own Skyline Diffusers using a pattern I got from the Internet, and the recommendations were to use a lighter type of wood, such as Pinus. The problem is it's still too heavy, once I'm going to hang it on my apartment. So I made some…
Henrique Nader
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Determine whether resonance/standing waves are from speakers or room?

I have two massive resonances (more than 12db above the response curve elsewhere) with my bookshelf monitors placed on a desk in a large furnished, carpeted room. One is at about 110 Hz and another at about 250 Hz. Are there any rules of thumb…
glenviewjeff
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Nice read about reverb

Not a question, but thought this was an interesting article about some reverb/acoustics in England :) http://www.bbc.co.uk/news/magazine-20773690
Fred Riding
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Do I really need to dump tons of sand into the stage i'm building?

I am building a 16x24x3 stage in a 4000 square foot warehouse, to be used principally to showcase music. A local audio guy has told me that I have to fill the wooden framed stage with sand. This appears like it is going to be very costly, so I…
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Why does the internet sound like a sine wave

I scraped a couple of webpages, then in java converted every letter into a number zero to nine dependent on how far along the alphabet it is. I then turned these into pairs of digits. I imported this raw into audacity, as unsigned eight bit stereo…
Evanson
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How to improve acoustics of a 16 meter square garage on a budget?

I'll be renting a garage now for practice. It will be used for several bands. The garage size is 16 square meters and it doesn't matter if it's loud outside (these garages are pretty far from the buildings so nobody cares). I really don't know…
Glorious Kale
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career in acoustics

hello, i am considering shifting my career path towards working in acoustics. in particular architectural acoustics, environmental acoustics and noise control. however, my academic background is in music technology and sound design. is it cardinal…
kampana
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rock wool absorption

Hi, I want to make my own bass trap and i can not find rock wool in 10 cm thickness. In terms of absorption quality is there any difference to stack two 5cm rock wool plates together to form a 10cm rock wool thickness ? It's hard to find 10 cm rock…
larvicide
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Interior ceiling sound insulation

I have a room where very loud sounds (140-160dB) are going to be produced on an occasional basis. I am trying to acoustically insulate the ceiling with the materials I have in my regional warehouse. I know I can't stop some sound from escaping to…
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