Editing Loudspeaker (section)

== Speaker systems ==
Speaker system design involves subjective perceptions of [[timbre]] and sound quality, measurements and experiments.<ref>{{Cite book |last1=Davis |first1=Don |first2=Carolyn |last2=Davis |date=1997 |title=Sound System Engineering |publisher=Focal Press |edition=2 |page=350 |chapter=Loudspeakers and Loudspeaker Arrays |isbn=978-0-240-80305-0 |chapter-url=https://books.google.com/books?id=ouyzH6vsIIwC&pg=PA350 |access-date=March 30, 2010 |quote=We often give lip service to the fact that audio allows its practitioners to engage in both art and science.}}</ref><ref>{{Cite journal|last=Fremer |first=Michael |date=April 2004 |title=Aerial Model 20T loudspeaker |journal=Stereophile |url=http://www.stereophile.com/floorloudspeakers/404aerial/# |access-date=March 30, 2010 }}</ref><ref>{{Cite news |url=https://www.nytimes.com/1993/06/06/arts/home-entertainment-speaker-design-goes-modern.html?pagewanted=1 |title=Speaker Design Goes Modern |last=Fantel |first=Hans |date=June 6, 1993 |work=The New York Times |access-date=March 30, 2010 }}</ref> Adjusting a design to improve performance is done using a combination of magnetic, acoustic, mechanical, electrical, and [[materials science]] theory, and tracked with high-precision measurements and the observations of experienced listeners. A few of the issues speaker and driver designers must confront are distortion, [[acoustic lobing]], phase effects, off-axis response, and crossover artifacts. Designers can use an [[anechoic chamber]] to ensure the speaker can be measured independently of room effects, or any of several electronic techniques that, to some extent, substitute for such chambers. Some developers eschew anechoic chambers in favor of specific standardized room setups intended to simulate real-life listening conditions.

[[File:Lautsprecher 4-wege 2.jpg|thumb|upright|A four-way, high fidelity loudspeaker system. Each of the four drivers outputs a different frequency range; the fifth aperture at the bottom is a [[bass reflex]] port.]]

Individual electrodynamic drivers provide their best performance within a limited frequency range. Multiple drivers (e.g. subwoofers, woofers, mid-range drivers, and tweeters) are generally combined into a complete loudspeaker system to provide performance beyond that constraint. The three most commonly used sound radiation systems are the cone, dome and horn-type drivers.

=== Full-range drivers ===
{{Main|Full-range speaker}}
A full- or wide-range driver is a speaker driver designed to be used alone to reproduce an audio channel without the help of other drivers and therefore must cover the audio frequency range required by the application. These drivers are small, typically {{convert|3|to|8|in|cm}} in diameter to permit reasonable high-frequency response, and carefully designed to give low-distortion output at low frequencies, though with reduced maximum output level. Full-range drivers are found, for instance, in public address systems, in televisions, small radios, intercoms, and some [[computer speaker]]s.

In [[hi-fi]] speaker systems, the use of wide-range drivers can avoid undesirable interactions between multiple drivers caused by non-coincident driver location or crossover network issues but also may limit frequency response and output abilities (most especially at low frequencies). Hi-fi speaker systems built with wide-range drivers may require large, elaborate or, expensive enclosures to approach optimum performance.

[[File:Fostex FE206e (modified) full-range drive unit loudspeaker, using a whizzer cone.jpg|A full-range drive unit loudspeaker using a whizzer cone|thumb]]

Full-range drivers often employ an additional cone called a ''whizzer'': a small, light cone attached to the joint between the voice coil and the primary cone. The whizzer cone extends the high-frequency response of the driver and broadens its high-frequency directivity, which would otherwise be greatly narrowed due to the outer diameter cone material failing to keep up with the central voice coil at higher frequencies. The main cone in a whizzer design is manufactured so as to flex more in the outer diameter than in the center. The result is that the main cone delivers low frequencies and the whizzer cone contributes most of the higher frequencies. Since the whizzer cone is smaller than the main diaphragm, output dispersion at high frequencies is improved relative to an equivalent single larger diaphragm.

Limited-range drivers, also used alone, are typically found in computers, toys, and [[clock radio]]s. These drivers are less elaborate and less expensive than wide-range drivers, and they may be severely compromised to fit into very small mounting locations. In these applications, sound quality is a low priority.

===Subwoofer===
{{Main|Subwoofer}}

A subwoofer is a woofer driver used only for the lowest-pitched part of the audio spectrum: typically below 200&nbsp;Hz for consumer systems,<ref name="crutchfield.com">[http://www.crutchfield.com/S-5VsEXVgtser/Learn/learningcenter/home/speakers_glossary.html Home Speakers Glossary]. Crutchfield.com (June 21, 2010). Retrieved on October 12, 2010.</ref> below 100&nbsp;Hz for professional live sound,<ref>{{cite web|url=http://www.prosoundweb.com/article/in_depth_the_aux_fed_subwoofer_technique_explained/P2/ |title=In-Depth: The Aux-Fed Subwoofer Technique Explained |last=Young |first=Tom |date=December 1, 2008 |work=Study Hall |publisher=ProSoundWeb |page=2 |access-date=March 3, 2010 |archive-url=https://web.archive.org/web/20100114121638/http://www.prosoundweb.com/article/in_depth_the_aux_fed_subwoofer_technique_explained/P2/ |archive-date=January 14, 2010 }}</ref> and below 80&nbsp;Hz in [[THX]]-approved systems.<ref name="DellaSala">{{cite web|url=http://www.audioholics.com/tweaks/get-good-bass/setting-the-subwoofer-lfe-crossover-for-best-performance|title=Setting the Subwoofer / LFE Crossover for Best Performance |last=DellaSala|first=Gene|date=August 29, 2004|work=Tips & Tricks: Get Good Bass|publisher=Audioholics|access-date=March 3, 2010}}</ref> Because the intended range of frequencies is limited, subwoofer system design is usually simpler in many respects than for conventional loudspeakers, often consisting of a single driver enclosed in a suitable enclosure.  Since sound in this frequency range can easily bend around corners by [[diffraction]], the speaker aperture does not have to face the audience, and subwoofers can be mounted in the bottom of the enclosure, facing the floor.  This is eased by the limitations of human hearing at low frequencies; Such sounds cannot be located in space, due to their large wavelengths compared to higher frequencies which produce differential effects in the ears due to shadowing by the head, and diffraction around it, both of which we rely upon for localization clues.

To accurately reproduce very low bass notes, subwoofer systems must be solidly constructed and properly braced to avoid unwanted sounds from cabinet vibrations. As a result, good subwoofers are typically quite heavy. Many subwoofer systems include integrated [[power amplifier]]s and electronic [[Infrasound|subsonic]]-filters, with additional controls relevant to low-frequency reproduction (e.g. a crossover knob and a phase switch). These variants are known as ''active'' or ''powered'' subwoofers.<ref>{{cite web |url=http://www.home-theater-designers.com/glossary.html |title=Glossary of Terms |work=Home Theater Design |publisher=ETS-eTech |archive-url=https://web.archive.org/web/20120723231911/http://www.home-theater-designers.com/glossary.html |archive-date=July 23, 2012 |page=1 |access-date=March 3, 2010 }}</ref> In contrast, ''passive'' subwoofers require external amplification.

In typical installations, subwoofers are physically separated from the rest of the speaker cabinets.  Because of propagation delay and positioning, their output may be out of phase with the rest of the sound.  Consequently, a subwoofer's power amp often has a phase-delay adjustment which may be used improve performance of the system as a whole. Subwoofers are widely used in large concert and mid-sized venue sound reinforcement systems. Subwoofer cabinets are often built with a [[bass reflex]] port, a design feature which if properly engineered improves bass performance and increases efficiency.

=== Woofer ===
{{Main|Woofer}}

A woofer is a driver that reproduces low frequencies. The driver works with the characteristics of the [[speaker enclosure]] to produce suitable low frequencies. Some loudspeaker systems use a woofer for the lowest frequencies, sometimes well enough that a subwoofer is not needed. Additionally, some loudspeakers use the woofer to handle middle frequencies, eliminating the mid-range driver.

=== Mid-range driver ===
{{Main|Mid-range speaker}}

A mid-range speaker is a loudspeaker driver that reproduces a band of frequencies generally between 1–6&nbsp;kHz, otherwise known as the ''mid'' frequencies (between the woofer and tweeter). Mid-range driver diaphragms can be made of paper or composite materials and can be direct radiation drivers (rather like smaller woofers) or they can be [[compression driver]]s (rather like some tweeter designs). If the mid-range driver is a direct radiator, it can be mounted on the front baffle of a loudspeaker enclosure, or, if a compression driver, mounted at the throat of a [[Horn loudspeaker|horn]] for added output level and control of radiation pattern.

=== Tweeter ===
{{Main|Tweeter}}
[[File:Tw15ul9.jpg|thumb|[[Exploded view drawing|Exploded view]] of a dome tweeter]]

A tweeter is a high-frequency driver that reproduces the highest frequencies in a speaker system.  A major problem in tweeter design is achieving wide angular sound coverage (off-axis response), since high-frequency sound tends to leave the speaker in narrow beams.  Soft-dome tweeters are widely found in home stereo systems, and horn-loaded compression drivers are common in professional sound reinforcement. Ribbon tweeters have gained popularity as the output power of some designs has been increased to levels useful for professional sound reinforcement, and their output pattern is wide in the horizontal plane, a pattern that has convenient applications in concert sound.<ref>{{cite web |last=Nieuwendijk |first=Joris A. |date=1988 |url=http://www.aes.org/e-lib/browse.cfm?elib=5129 |title=Compact Ribbon Tweeter/Midrange Loudspeaker |publisher=Audio Engineering Society }}</ref>

===Coaxial drivers===
A coaxial driver is a loudspeaker driver with two or more combined concentric drivers. Coaxial drivers have been produced by [[Altec Lansing|Altec]], [[Tannoy]], [[Pioneer Corporation|Pioneer]], [[KEF]], SEAS, B&C Speakers, BMS, [[Cabasse (company)|Cabasse]] and [[Genelec]].<ref>{{cite web |title=Genelec 8260A Technical Paper |url=http://www.genelec.com/documents/other/Genelec%208260A%20Technical%20Paper.pdf |date=September 2009 |publisher=Genelec |pages=3–4 |access-date=September 24, 2009 |archive-url=https://web.archive.org/web/20101230170304/http://www.genelec.com/documents/other/Genelec%208260A%20Technical%20Paper.pdf |archive-date=December 30, 2010 }}</ref>
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