Editing Loudspeaker (section)

===Crossover===
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{{Main|Audio crossover}}
[[File:Passive Crossover.svg|thumb|A passive crossover]]
[[File:Active Crossover.svg|thumb|A bi-amplified system with an active crossover]]

Used in '''multi-driver speaker systems''', the crossover is an assembly of filters that separate the input signal into different [[frequency band]]s according to the requirements of each driver. Hence the drivers receive power only in the sound frequency range they were designed for, thereby reducing distortion in the drivers and interference between them. Crossovers can be ''passive'' or ''active''.

A [[Audio crossover#Passive crossovers|passive crossover]] is an electronic circuit that uses a combination of one or more [[resistor]]s, inductors and [[capacitor]]s. These components are combined to form a filter network and are most often placed between the full frequency-range power amplifier and the loudspeaker drivers to divide the amplifier's signal into the necessary frequency bands before being delivered to the individual drivers. Passive crossover circuits need no external power beyond the audio signal itself, but have some disadvantages: they may require larger inductors and capacitors due to power handling requirements. Unlike active crossovers which include a built-in amplifier, passive crossovers have an inherent attenuation within the [[passband]], typically leading to a reduction in [[damping factor]] before the voice coil.{{Citation needed|date=April 2024}}

An [[Audio crossover#Active crossovers|active crossover]] is an electronic filter circuit that divides the signal into individual frequency bands ''before'' power amplification, thus requiring at least one power amplifier for each band.{{Citation needed|date=April 2024}} Passive filtering may also be used in this way before power amplification, but it is an uncommon solution, being less flexible than active filtering. Any technique that uses crossover filtering followed by amplification is commonly known as bi-amping, tri-amping, quad-amping, and so on, depending on the minimum number of amplifier channels.<ref>Boston Acoustic Society. ''The B.A.S. Speaker'', September 1978. Peter W. Mitchell: "The D-23 crossover can be used for bi-amping, tri-amping, or even quad-amping."</ref>

Some loudspeaker designs use a combination of passive and active crossover filtering, such as a passive crossover between the mid- and high-frequency drivers and an active crossover for the low-frequency driver.<ref>{{cite web |publisher=EAW |url=http://www.eaw.com/products/KF/kf300.html |title=KF300/600 Series&nbsp;— Compact three-way VAT Systems |archive-url=https://web.archive.org/web/20120424065507/http://www.eaw.com/products/kf/kf300.html |archive-date=April 24, 2012 }}</ref><ref>{{cite web |url=http://www.yorkville.com/products.asp?cat=38&id=268&type=29 |title=U215 Speaker&nbsp;– 1600w 2x15 / 3x5 inch / 1 inch |publisher=Yorkville |archive-url=https://web.archive.org/web/20120322012059/http://www.yorkville.com/products.asp?cat=38&id=268&type=29 |archive-date=March 22, 2012 }}</ref>

Passive crossovers are commonly installed inside speaker boxes and are by far the most common type of crossover for home and low-power use. In car audio systems, passive crossovers may be in a separate box, necessary to accommodate the size of the components used. Passive crossovers may be simple for low-order filtering, or complex to allow steep slopes such as 18 or 24&nbsp;dB per octave. Passive crossovers can also be designed to compensate for undesired characteristics of driver, horn, or enclosure resonances, and can be tricky to implement, due to component interaction. Passive crossovers, like the driver units that they feed, have power handling limits, have [[insertion loss]]es, and change the load seen by the amplifier. The changes are matters of concern for many in the hi-fi world.{{Citation needed|date=April 2024}} When high output levels are required, active crossovers may be preferable. Active crossovers may be simple circuits that emulate the response of a passive network or may be more complex, allowing extensive audio adjustments. Some active crossovers, usually digital loudspeaker management systems, may include electronics and controls for precise alignment of phase and time between frequency bands, equalization, [[dynamic range compression]] and [[limiting]].{{Citation needed|date=April 2024}}
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