Acoustics

folk myth that the sound of the ocean may be heard through seashells

thumb|305px| An example of rarefaction is also as a Phase (waves)|phase in a [[sound wave or phonon. Half of a sound wave is made up of the compression of the medium, and the other half is the decompression or rarefaction of the medium.]] Rarefaction is the reduction of an item's density, the opposite of compression. Like compression, which can travel in waves (sound waves, for instance), rarefaction waves also exist in nature. A common rarefaction wave is the area of low relative pressure following a shock wave (see picture).

theory

level of background noise in a signal

thumb|Obstetric ultrasonography of [[twins at a gestational age of almost 9 weeks. The mother’s and the twins’ bodies have a higher echogenicity than the amniotic fluid around them. The standard representation is brighter color for higher echogenicity, giving the almost anechoic fluid an almost black appearance.]] Echogenicity (sometimes as echogenecity) or echogeneity is the ability to bounce an echo, e.g. return the signal in medical ultrasound examinations. In other words, echogenicity is higher when the surface bouncing the sound echo reflects increased sound waves. Tissues that have highe

Recording method

In acoustics, microbaroms, also known as the "voice of the sea", are a class of atmospheric infrasonic waves generated in marine storms

blacksmith's hammers associated with discovery of consonance

increase in bass or low frequency response when a sound source is close to a microphone

interior chamber of a wind instrument

frequency dispersion applied to sound and seismic waves

type of material

or interdigitated transducer, a sensor and transmitter for a surface acoustic wave

subjective perception, when listening to a certain sound situation

water-based rocket launch noise control

conveying information through mechanical (seismic) vibrations of the substrate

time-averaged sound energy in a volume

claim that presence of ultrasound has measureable reactions

instantaneous displacement of a particle from its equilibrium position in a medium as it transmits a sound wave

method of loudspeaker cabinet design

in cryptography, a side channel attack which exploits sounds

hypothetical neural stimulation for altering states of consciousness

formula for sound intensity loss in a Newtonian fluid

room designed to create reverberation

wave that can travel around a concave surface

thumb|A recording setup using auralization; two microphones are used to emulate the sound heard from both ears. Auralization is a procedure designed to model and simulate the experience of acoustic phenomena rendered as a soundfield in a virtualized space. This is useful in configuring the soundscape of architectural structures, concert venues, and public spaces, as well as in making coherent sound environments within virtual immersion systems.

thin vibrating layer that produces sound

cavity which amplifies sound waves

sound transmission method

a vibrating object which produces a sound; any kind of device made or used for the purpose of generating sound

fields of sound which spread less than most transmissions

the study of piano sounds and the design elements which are involved

device that converts heat into sound by creating a self-amplifying standing wave

diffraction of waves in the atmosphere

Base 2 logarithmically-spaced frequency bands

coherent movements of atoms of the lattice out of their equilibrium positions