Changes

==Speed of sound==

==Speed of sound==

The speed at which sound travels depends on the medium through which the waves are passing, and is often quoted as a fundamental property of the material. In general, the speed of sound is proportional to the square root of the ratio of the [[elastic modulus]] (stiffness) of the medium and its density. Those physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in air and other gases depends on [[temperature]]. In air at sea level, the speed of sound is approximately 769.5 mph (1,238.3 kph) at 68º F (20º C),[http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html Speed of Sound] in water 3,315.1 mph (5,335.1 kph) at 20º C (68º F),[http://hypertextbook.com/facts/2000/NickyDu.shtml Speed of Sound in Water] and in steel 13,332.1 mph (21,446 kph) [http://library.thinkquest.org/19537/Physics4.html The Soundry: The Physics of Sound]. The speed of sound is also slightly sensitive (to second order) to the sound amplitude, resulting in nonlinear propagation effects, such as the weak production of harmonics and the mixing of tones. (see [[parametric array]]).

The speed at which sound travels depends on the medium through which the waves are passing, and is often quoted as a fundamental property of the material. In general, the speed of sound is proportional to the square root of the ratio of the [[elastic modulus]] (stiffness) of the medium and its density. Those physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in air and other gases depends on [[temperature]]. In air at sea level, the speed of sound is approximately 769.5 mph (1,238.3 kph) at 68º F (20º C),[https://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html Speed of Sound] in water 3,315.1 mph (5,335.1 kph) at 20º C (68º F),[https://hypertextbook.com/facts/2000/NickyDu.shtml Speed of Sound in Water] and in steel 13,332.1 mph (21,446 kph) [https://library.thinkquest.org/19537/Physics4.html The Soundry: The Physics of Sound]. The speed of sound is also slightly sensitive (to second order) to the sound amplitude, resulting in nonlinear propagation effects, such as the weak production of harmonics and the mixing of tones. (see [[parametric array]]).

==Sound pressure==

==Sound pressure==

===Examples of sound pressure and sound pressure levels===

===Examples of sound pressure and sound pressure levels===

See also [[Sound pressure#Examples of sound pressure and sound pressure levels|the Sound pressure article]]. A larger dB chart can be found here:

See also [[Sound pressure#Examples of sound pressure and sound pressure levels|the Sound pressure article]]. A larger dB chart can be found

[[http://makeitlouder.com/Decibel%20Level%20Chart.txt]]

[https://makeitlouder.com/Decibel%20Level%20Chart.txt here].

 

== Equipment for dealing with sound ==

== Equipment for dealing with sound ==

Equipment for generating or using sound includes [[musical instrument]]s, [[hearing aid]]s, [[sonar]] systems and [[sound reproduction]] and broadcasting equipment.  Many of these use electro-acoustic transducers such as [[microphone]]s and [[loudspeaker]]s.

Equipment for generating or using sound includes [[musical instrument]]s, [[hearing aid]]s, [[sonar]] systems and [[sound reproduction]] and broadcasting equipment.  Many of these use electro-acoustic transducers such as [[microphone]]s and [[loudspeaker]]s.

== See also ==

== See also ==

*[[Acoustics]] | [[Auditory imagery]] | [[Audio signal processing]] | [[Beat (acoustics)|Beat]]s | [[Cycle (music)|Cycles]] | [[Diffraction]] | [[Doppler effect]] | [[Echo]] | [[Music]] | [[Note]] | [[Phonons]] | [[Physics of music]] | [[Pitch (music)|Pitch]] | [[Radiation of sound]] | [[Resonance]] | [[Rijke tube]] | [[Reflection (physics)|Reflection]] | [[Reverberation]] | [[Sonic weaponry]] | [[Sound localization]] | [[Soundproofing]] | [[Rotary Woofer]] | [[Steam whistle]] | [[Timbre]] | [[Voyager Golden Record]] | [[Audio bit depth]] | [[Sound branding]] | [[Sounds and Mind]]

*[[Acoustics]] | [[Auditory imagery]] | [[Echo]] | [[Music]] | [[Note]] | [[Resonance]] | [[Sounds and Mind]]

 

== External links ==

== External links ==

*[http://hyperphysics.phy-astr.gsu.edu/hbase/sound/soucon.html HyperPhysics: Sound and Hearing]

*[https://hyperphysics.phy-astr.gsu.edu/hbase/sound/soucon.html HyperPhysics: Sound and Hearing]

*[http://www.acoustics.salford.ac.uk/schools/index.htm Sounds amazing a learning resource for sound and waves]

*[https://www.acoustics.salford.ac.uk/schools/index.htm Sounds amazing a learning resource for sound and waves]

*[http://www.phys.unsw.edu.au/~jw/hearing.html Hearing curves and on-line hearing test]

*[https://www.phys.unsw.edu.au/~jw/hearing.html Hearing curves and on-line hearing test]

*[http://www.audiodesignline.com/howto/audioprocessing/193303241 Audio for the 21st Century]

*[https://www.audiodesignline.com/howto/audioprocessing/193303241 Audio for the 21st Century]

*[http://www.sengpielaudio.com/calculator-soundlevel.htm Conversion of sound units and levels]

*[https://www.sengpielaudio.com/calculator-soundlevel.htm Conversion of sound units and levels]

*[http://www.acoustics.salford.ac.uk/schools/index.htm Sounds Amazing a learning resource for sound and waves]

*[https://www.acoustics.salford.ac.uk/schools/index.htm Sounds Amazing a learning resource for sound and waves]

*[http://www.sengpielaudio.com/Calculations03.htm Sound calculations]

*[https://www.sengpielaudio.com/Calculations03.htm Sound calculations]

 

for more see: [http://en.wikipedia.org/w/index.php?title=Sound&action=edit]

[[Category: General Reference]]

[[Category: General Reference]]

[[Category: Physics]]

[[Category: Physics]]