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Topic: Sound intensity

Related Topics

Sound intensity level

Sound pressure level

Particle velocity

Sound power

Sound energy flux

Sound power level

Sound impedance

Particle velocity level

Acoustics

Sound

Speed of sound

Threshold of pain

Radiation of sound

Psychoacoustics

Decibel

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	Loudness
		Sound loudness is a subjective term describing the strength of the ear's perception of a sound.
		This is one of the motivations for using the decibel scale to measure sound intensity.
		A widely used "rule of thumb" for the loudness of a particular sound is that the sound must be increased in intensity by a factor of ten for the sound to be perceived as twice as loud.
	hyperphysics.phy-astr.gsu.edu /hbase/sound/loud.html (894 words)

	Sound Intensity
		To assess sound loudness, as distinct from an objective intensity measurement, the sensitivity of the ear must be factored in.
		Since audible sound consists of pressure waves, one of the ways to quantify the sound is to state the amount of pressure variation relative to atmospheric pressure caused by the sound.
		Sound level measurements in decibels are generally referenced to a standard threshold of hearing at 1000 Hz for the human ear which can be stated in terms of sound intensity:
	hyperphysics.phy-astr.gsu.edu /hbase/sound/intens.html (493 words)

	Learn more about Sound in the online encyclopedia. (Site not responding. Last check: 2007-10-07)
		In geography, a sound is a large ocean inlet, or a narrow ocean channel between two bodies of land.
		Most sounds are combinations of signals, but a theoretical pure sound can be described as having a given speed of oscillation or frequency measured in hertz (Hz) and amplitude or energy with measures such as decibel level.
		The amplitude of a sound wave is measured in pascals, and the intensity of a sound is measured in decibels relative to a stated scale.
	www.onlineencyclopedia.org /s/so/sound.html (459 words)

	Sound intensity - Wikipedia, the free encyclopedia
		:The term "intensity" is used exclusively for the measurement of sound in watts per unit area.
		Sound intensity is not the same physical quantity as sound pressure.
		Hearing is directly sensitive to sound pressure which is related to sound intensity.
	en.wikipedia.org /wiki/Sound_intensity (173 words)

	Encyclopedia: Sound
		Sound is the vibration of matter, as perceived by the sense of hearing.
		In sound waves parts of matter (molecules or groups of molecules) move in a direction of the spreading of the disturbance (as opposite to transversal waves).
		A sound wave is usually represented graphically by a wavy, horizontal line; the upper part of the wave (the crest) indicates a compression and the lower part (the trough) indicates a rarefaction.
	www.nationmaster.com /encyclopedia/Sound (902 words)

	Facts about topic: (Sound intensity) (Site not responding. Last check: 2007-10-07)
		The usual context is the measurement of sound intensity in the air at a listener's location.
		Sound intensity level (additional info and facts about Sound intensity level) is a different measure used in acoustics (The study of the physical properties of sound).
		Note: The term "intensity (The amount of energy transmitted (as by acoustic or electromagnetic radiation)) " is used exclusively for the measurement of sound in watts per unit area.
	www.absoluteastronomy.com /encyclopedia/s/so/sound_intensity.htm (315 words)

	Physics
		Sound intensity is related to the ability to hear different frequencies since our ears are able to hear middle frequencies better, 2000-4000Hz.
		Sound intensity, which is measured in W/m^2 is different from sound intensity level, measured in dB.
		The sound intensity is derived into phons which are a unit for loudness, the intensity level in dB at 1000Hz.
	www.hivepc.com /physics/sound.html (877 words)

	The Physics Classroom
		As a sound wave carries its energy through a two-dimensional or three-dimensional medium, the intensity of the sound wave decreases with increasing distance from the source.
		Applied to the diagram at the right, the intensity at point B is one-fourth the intensity as point A and the intensity at point C is one-sixteenth the intensity at point A. Since the intensity-distance relationship is an inverse relationship, an increase in one quantity corresponds to a decrease in the other quantity.
		This intensity corresponds to a pressure wave in which a compression of the particles of the medium increases the air pressure in that compressional region by a mere 0.3 billionths of an atmosphere.
	www.physicsclassroom.com /Class/sound/U11L2b.html (1282 words)

	Sound Article, Sound Information (Site not responding. Last check: 2007-10-07)
		Sound is defined as a mechanical compression and rarefaction or a longitudinaldisplacement wave that propagates through a medium (solid, liquid or gas).
		Sounds that are sine waveswith a single pair of frequency and amplitude components are generally perceived as a pure tone.
		While the sound may still be referred to in general use as a single frequency (for example, a piano striking the A above middle C is said to beplaying a note at 440 Hz) the sound you perceive will be colored by all of the frequencycomponents and their relative amplitudes (see timbre.)
	www.anoca.org /sounds/waves/sound.html (615 words)

	Sound Power and Intensity
		For a sound wave, the amount of energy transported is proportional to the square of the amplitude of the wave.
		Both sound pressure level and sound intensity level are purported to measure the same thing: the loudness of a sound that we hear.
		The next step to show the equality of sound pressure level and sound intensity level is to realize that the intensity in a sound wave is proportional to the square of the amplitude of the sound wave.
	hep.physics.indiana.edu /~rickv/Sound_intensity.html (912 words)

	Acoustics Monitoring Program
		A propagating sound wave consists of alternating compressions and rarefactions which are detected by a receiver as changes in pressure.
		The amplitude of a sound wave is proportional to the maximum distance a vibrating particle is displaced from rest.
		To the human ear, an increase in frequency is perceived as a higher pitched sound, while an increase in amplitude is perceived as a louder sound.
	www.pmel.noaa.gov /vents/acoustics/tutorial/tutorial.html (398 words)

	sound intensity -- Britannica Concise Encyclopedia - The online encyclopedia you can trust!
		When this ratio is 10, the difference in intensity of the sounds is said to be one bel, a unit named in honour of the United States inventor Alexander Graham Bell.
		Sound intensity may be measured in units of energy or work—e.g., microjoules (10-6 joule) per second per square centimetre—or in units of power, as microwatts (10-6 watt) per square centimetre.
		A purely subjective definition of sound is also possible, as that which is perceived by the ear, but it is not particularly illuminating and is unduly restrictive, for it is useful to speak of sounds that cannot be heard by the human ear, such as those that are...
	www.britannica.com /ebc/article-9068800 (1097 words)

	Sound intensity level - Wikipedia, the free encyclopedia
		Sound intensity level or acoustic intensity level is a logarithmic measure of the sound intensity in comparison to the reference level of 0 dB (decibels).
		The measure of a ratio of two sound intensities is
		The sound intensity level is given the letter "L
	en.wikipedia.org /wiki/Sound_intensity_level (97 words)

	Sound_Intensity (Site not responding. Last check: 2007-10-07)
		The sound energy transmitted per unit time through a unit area, thereby being a measure of the magnitude of a sound.
		for the conversion of intensity ratios to decibels.
		Sound intensity is proportional to the square of the
	www.sfu.ca /sonic-studio/handbook/Sound_Intensity.html (95 words)

	Sound Intensity-Technical Information
		Sound Intensity is a time-averaged, directional quantity that measures the rate of energy flowing through a specified unit area.
		By comparing the differences between the sound signal at the two microphones, the sound intensity analyzer can compute both the sound pressure and particle velocity at the mid-point between the two microphones, and can multiply the two together to compute the sound intensity.
		Because sound intensity is based on both acoustic pressure and velocity it has a direction.
	www.soundintensity.com /si_technical.htm (284 words)

	Sound Intensity
		Sound intensity and vibration measurements were performed under 'maximum rated power conditions' to determine the sound power radiated from each source, including gas turbines, inlets, exhausts, a two-stage compressor, gearboxes, piping, pinch valves.
		Sound intensity measurements used to quantify noise from components of a pellet mill for photocopier toner, and associated piping; removable noise control measures developed for selected process components.
		Acoustic intensity techniques were utilized to measure the sound power and determine the relative contribution of various sources associated with blowers, fans and burners at this large refinery in Ontario.
	www.soundintensity.com /si_projects.htm (424 words)

	Inverse Square Law for Sound
		The sound intensity from a point source of sound will obey the inverse square law if there are no reflections or reverberation.
		A plot of the drop of sound intensity according to the inverse square law emphasizes the rapid loss associated with the inverse square law.
		Sound from a point source obeys the inverse square law.
	hyperphysics.phy-astr.gsu.edu /hbase/acoustic/invsqs.html (132 words)

	Intensity (Site not responding. Last check: 2007-10-07)
		Sound originates when a vibrating source disturbs the air in a quasi-periodic fashion and sends a sound wave travelling through it.
		Another way of saying this is that a sound source radiates acoustical energy which is transferred to the medium (air) and this energy propagates through the air in the form of a sound wave.
		It is the amplitude of the eardrum oscillations which leads to the sensation of loudness and this amplitude is directly related to the average pressure variation p, of the incoming sound wave.
	www.ndr.hu /sound/intensity/Intensity1.html (310 words)

	00.05.10: Discovering the Mathematics of Sound
		Sound is the form of energy which most of us seem to take for granted.
		In the case of sound waves, the disturbance is in the form of a change in pressure and density which is sometimes described as a vibration in the medium.
		If a sound source 100 feet away has an intensity of 90 dB and you were to move to a distance 200 feet from the source, the intensity of the sound would drop by 6 dB (if the distance from the source is doubled, there is a drop of 6 dB).
	www.yale.edu /ynhti/curriculum/units/2000/5/00.05.10.x.html (3579 words)

	Sound intensity on the basilar membrane as square of amplitude on the eardrum
		Sound intensity on the basilar membrane as square of amplitude on the eardrum
		But there is also, as a measure for sound, the contribution of the frequency dependent part of the sound intensity signal, for every combination of frequencies and in the sound signal represented in the intensity spectrum as pure tone signals:
		The total stimulus on the basilar membrane, i.e., the sound intensity signal, is transferred by the combined sensing of outer hair cells and inner hair cells into the signal on the auditory nerve and finally sent to the brain.
	www.slechthorend-plus.nl /fysica/en/heerens_02expl.htm (2743 words)

	Physics Demonstrations - Sound
		Sound appears to be a topic distinct from motion and heat.
		A dramatic illustration of the variation of the speed of sound with the density of a gas is performed by breathing a low density and a high density gas and talking as the gas is expelled from the lungs.
		The speed of sound in a gas is proportional to the square root of its density.
	sprott.physics.wisc.edu /demobook/chapter3.htm (7341 words)

	Sound level SPL in dB - pressure level L sound pressure p sound intensity I - dB conversion of sound units calculating ... (Site not responding. Last check: 2007-10-07)
		Sound level SPL in dB - pressure level L sound pressure p sound intensity I - dB conversion of sound units calculating spl sound level calculation air - sengpielaudio
		To speak of the intensity of a sound pressure is nonsense.
		Sound pressure and sound intensity are really not the same.
	www.sengpielaudio.com /calculator-soundlevel.htm (303 words)

	Physics 128 Lecture: Sound
		The power of a sound wave is proportional to the amplitude of the wave squared,and the frequency of the wave squared.
		The intensity I of a wave, or the power per unit area, is the rate at which energy is transported by the wave through a unit area A perpendicular to the direction of travel of the wave.
		The intensity of a periodic sound wave is proportional to the square of the amplitude and the square of the frequency of the wave.
	www.cord.edu /dept/physics/p128/lecture98_34.html (917 words)

	BBC NEWS \| Magazine \| Can sound really travel 200 miles?
		Sound can travel as long as there is something for it to travel through.
		During the first world war the sound from the guns on the Somme could be clearly heard in parts of the UK on the arc of a circle.
		Sound is much slower than light and therefore would take longer to reach the Netherlands and Belgium.
	news.bbc.co.uk /1/hi/magazine/4521232.stm (1788 words)

	Gracey, Bruel & Kjaer 4297 Sound Intensity Calibrator for Hire
		Sound Intensity Calibrator type 4297 is used for on-site sound-pressure calibration and pressure residual intensity index verification, with the type 2260E Sound Intensity Meter and 3595 Sound Intensity Probe Kit.
		Sound Intensity Calibrator Type 4297 enables instruments which measure sound intensity to be accurately calibrated.
		Type 4297 is intended for use with Bruel and Kjaer Sound Intensity Probes Type 3583, 3584 and 3595 (or earlier Types 3545 or 3548) with Sound Intensity Microphone Pair Type 4197 (or earlier Type 4181).
	www.gracey.com /descriptions/bk-4297-d1.htm (591 words)

	The Decibel Scale for Sound Intensity and Pressure Robert F
		Intensity is the amount of energy transmitted per second over an area of a square meter.
		The sound intensities that human ears are sensitive to are very small compared to a watt, but still very wide between the weakest sound detectible and the strongest that does not cause pain (or damage the ear).
		This intensity was chosen as the standard reference level because it is approximately the weakest intensity of a pure tone at 1000 Hz that can be detected by human listeners, that is, an auditory threshold.
	www.cs.indiana.edu /~port/teach/641/decibel_scale.html (594 words)

	Sound Intensity Meters, Probes and Calibrators for Hire (Site not responding. Last check: 2007-10-07)
		Sound intensity probes are directional, so you can isolate and measure noise sources in reverberant noise fields, i.e.
		Sound level meter microphones are omni directional, by design, so the traditional measurement of sound power involved expensive anechoic or fully reverberant test rooms.
		Sound intensity probes, on the other hand, enable you to derive the sound power from the measured intensity of a noise source in the work place *.
	www.gracey.com /prod-07a.htm (599 words)

	Physics 20: Characteristics of Sound - Intensity
		The intensity of sound is a measure of the average rate of sound energy flow per unit area across a surface perpendicular to the direction of propagation.
		Explain that the intensity of a sound, as well as its duration, determine the extent of hearing damage that could occur from it.
		Also, the ear is responsive to sound intensities over a range of about 14 orders of magnitude (but roughly a 25% increase in intensity is required to perceive a change).
	www.sasked.gov.sk.ca /docs/physics/u5c12phy.html (1290 words)

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