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[[File:Speaker-driver back.jpg|150px|thumbnail|The back of a speaker driver]]

[[File:Speaker-driver back.jpg|150px|thumbnail|The back of a speaker driver]]

An '''Audio speaker''' (or Loudspeaker) is an electronic device which produces sound waves.  This is accomplished by causing vibrations which cause the air pressure to fluctuate slightly in waves.  The more rapid these fluctuations are (the higher the frequency of fluctuation) the higher the received pitch is.  The stronger each fluctuation is (the greater the amplitude), the greater the volume of the sound.

An '''Audio speaker''' (or Loudspeaker) is an electronic device which produces sound waves.  This is accomplished by generating vibrations which cause the air pressure to fluctuate slightly in waves.  The more rapid these fluctuations are (the higher the frequency of fluctuation) the higher the perceived pitch is.  The stronger each fluctuation is (the greater the amplitude), the greater the volume of the sound.

==Typical construction==

==Typical construction==

[[File:SpkFrontCutawayView.svg.png|thumbnail|A diagram of a driver]]

[[File:SpkFrontCutawayView.svg.png|thumbnail|A diagram of a driver]]

Each modern dynamic speaker contains a number of parts working together. Every speaker contains one or more driver, which is the device to actually produce sound.  Each driver contains a ''diaphragm'' (a flexible cone or dome, made of paper, plastic, or metal), which is attached to a flexible rim, called the ''suspension'' (or ''surround'').  The suspension is attached to the driver's frame, which is called the ''basket''.  The inner part of the diaphragm (the back of the concave surface) is attached to the ''voice coil''.  This voice coil is then attached to the basket by a ''spider'' (a ring of flexible material) which allows vibration but keeps the coil in place.<ref>http://www.physics.org/article-questions.asp?id=54 Retrieved September 30, 2016</ref><ref>electronics.howstuffworks.com/speaker4.htm Retrieved September 30, 2016</ref><br />

Each modern dynamic speaker contains a number of parts working together. Every speaker contains one or more driver, which is the device to actually produce sound.  Each driver contains a ''diaphragm'' (a flexible cone or dome, made of paper, plastic, or metal), which is attached to a flexible rim, called the ''suspension'' (or ''surround'').  The suspension is attached to the driver's frame, which is called the ''basket''.  The inner part of the diaphragm (the back of the concave surface) is attached to the ''voice coil''.  This voice coil is then attached to the basket by a ''spider'' (a ring of flexible material) which allows vibration but keeps the coil in place.<ref>http://www.physics.org/article-questions.asp?id=54 Retrieved September 30, 2016</ref><ref>electronics.howstuffworks.com/speaker4.htm Retrieved September 30, 2016</ref><br />

Several of these drivers are installed into an enclosure (except in rare cases, when only one is needed).  Many speakers are designed generically and sold for off-the-shelf use.  However, speakers can also be custom designed, which generally results in better sound quality, since they can be made specifically for the kind (or genre) of sound they will be reproducing.  Some speakers are even installed into enclosures which also function as furniture.

Several of these drivers are usually installed into an enclosure (except in rare cases, when only one is needed).  Many speakers are designed generically and sold for off-the-shelf use.  However, speakers can also be custom designed, which generally results in better sound quality, since they can be made specifically for the kind (or genre) of sound they will be reproducing.  Some speakers are even installed into enclosures which also function as furniture.

==Operation==

==Operation==

====Subwoofers====

====Subwoofers====

Subwoofers can produce sounds between 20 and 200Hz.  Although they have a small auditory range, multiple drivers are usually installed in each enclosure.  Unlike midwoofers, subwoofers can produce equal quality throughout their limited auditory range.<ref name="eBay">http://www.ebay.com/gds/Woofer-vs-Subwoofer-Is-There-Really-a-Difference-/10000000177630901/g.html Retrieved September 30, 2016</ref>

Subwoofers can produce sounds between 20 and 200Hz.  Although they have a small auditory range, multiple drivers are usually installed in each enclosure.  Unlike midwoofers, subwoofers can produce equal quality throughout their limited auditory range.<ref name="eBay">http://www.ebay.com/gds/Woofer-vs-Subwoofer-Is-There-Really-a-Difference-/10000000177630901/g.html Retrieved September 30, 2016</ref>

====Rotary subwoofers====

====Rotary subwoofers====

A less common kind of subwoofer is the rotary subwoofer, which uses fans instead of the diaphragm and magnet design.  Rather than moving a diaphragm to create sound waves, the fans are used to make pressure waves. These can produce sounds at 20Hz and below, and make them audible when they usually would not be.<ref name="eBay">http://www.ebay.com/gds/Woofer-vs-Subwoofer-Is-There-Really-a-Difference-/10000000177630901/g.html Retrieved September 30, 2016</ref>

A less common kind of subwoofer is the rotary subwoofer, which uses fans instead of the diaphragm and magnet design.  Rather than moving a diaphragm to create sound waves, the fans are used to make pressure waves. These can produce sounds at 20Hz and below, and make them audible when they usually would not be.<ref name="eBay">http://www.ebay.com/gds/Woofer-vs-Subwoofer-Is-There-Really-a-Difference-/10000000177630901/g.html Retrieved September 30, 2016</ref>

Although much less common, kinds of speakers other than dynamic also exist.  These are a few other kinds:

Although much less common, kinds of speakers other than dynamic also exist.  These are a few other kinds:

===Electrostatic speakers===

===Electrostatic speakers===

Electrostatic speakers also use electromagnetism, but in an entirely different way.  A pair of conductive plates are placed on either side of a flat diaphragm, which a narrow gap in between them.  The plates are then charged, so that the diaphragm has a positive charge on one side, and a negative charge on the other.  Now, the audio signal is run through the suspended diaphragm.  As the audio signal flows, the diaphragm is rapidly cycled between a positive and negative charge.  Opposite charges attract, so while charged negative, it pulls towards the positive plate, and while charged positive, it pulls towards the negative plate.  This process takes place so rapidly that high-frequency sound is produced. In fact, this system tends to respond more quickly than the traditional dynamic speaker, which can be useful in some situations.<ref name="howstuffworks11">http://electronics.howstuffworks.com/speaker11.htm Retrieved September 30, 2016</ref>

Electrostatic speakers also use electromagnetism, but in an entirely different way.  A pair of conductive plates are placed on either side of a flat diaphragm, with a narrow gap in between them.  The plates are then charged, so that the diaphragm has a positive charge on one side, and a negative charge on the other.  Now, the audio signal is run through the suspended diaphragm.  As the audio signal flows, the diaphragm is rapidly cycled between a positive and negative charge.  Opposite charges attract, so while charged negative, it pulls towards the positive plate, and while charged positive, it pulls towards the negative plate.  This process takes place so rapidly that high-frequency sound is produced. In fact, this system tends to respond more quickly than the traditional dynamic speaker, which can be useful in some situations.<ref name="howstuffworks11">http://electronics.howstuffworks.com/speaker11.htm Retrieved September 30, 2016</ref>

===Planar magnetic===

===Planar magnetic===