{{Short description|Loudspeaker driver}} [[File:Midrange-speaker.png|thumb|Cutaway view of a dynamic mid-range speaker {{olist |Magnet |Cooler |Voicecoil |Suspension |Membrane}}]]
A '''mid-range speaker''' is a [[loudspeaker]] driver that reproduces sound in the frequency range from 200 to 2,000 [[Hz]].<ref>{{cite journal |url=https://books.google.com/books?id=XyEDAAAAMBAJ&pg=RA3-PA196 |last1=Luckett |first1=Hubert |last2=Gorman |first2=Robert |title=How to Choose the Right Loudspeaker |journal=Popular Science |date=February 1957 |page=196 |volume=170 |number=2 |issn=0161-7370 |publisher=Bonnier Corporation}}</ref>
Mid-range drivers are usually cone types or, less commonly, dome types, or [[Compression_driver|compression horn drivers]]. The radiating diaphragm of a cone mid-range unit is a truncated cone, with a voice coil attached at the neck, along with the spider portion of the suspension, and with the cone surround at the wide end. Cone mid-range drivers typically resemble small [[woofer]]s. The most common material used for mid-range cones is [[paper]], occasionally impregnated and/or surface-treated with [[polymer]]s or [[resin]]s in order to improve vibrational damping. Other mid-range cone materials include plastics such as [[polypropylene]], Cobex, Bextrene, woven [[Kevlar]], fiberglass, [[carbon fiber]], or light metal [[alloy]]s based on [[aluminium]], [[magnesium]], [[titanium]], or other alloys. The radiating surface of a dome mid-range is typically a 90-degree section of a sphere, made from cloth, metal, or plastic film, with its suspension and voice coil co-located at the outer edge of the dome. Most professional [[concert]] mid-range drivers are [[compression driver]]s coupled to [[Horn loudspeaker|horns]]. A very few mid-ranges are [[electrostatic]] drivers, planar magnetic drivers, or ribbon drivers.
A mid-range driver is called upon to handle the most significant part of the audible sound spectrum, the region where the most [[fundamental frequencies]] are emitted by musical instruments, and, most importantly, the human voice. This region contains most sounds that are the most familiar to the human ear, and where discrepancies from faithful reproduction are most easily observed. It is therefore paramount that a mid-range driver of good quality be capable of low-distortion reproduction.
Many [[television set]]s and small radios, especially AM receivers, have only a single mid-range driver, or two for stereo sound. Some mid to high-end TV sets include a larger [[woofer]]. With human speech being the most important aspect of television audio and AM radio, it works out well. Since the ear is most sensitive to the middle frequencies produced by a mid-range driver and amplifier, both can be low power, while still delivering what is perceived to be good sound, both in terms of volume and quality.
Many [[laptop]]s and [[smartphone]]s are also small radios, have only a single mid-range speaker, or two mid-range speakers for stereo sound.
==Installation issues== Mid-range drivers are usually used in three-way multi-driver speaker systems. There are, therefore, special considerations involved in the acoustic join between the mid-range and both the low frequency ([[woofer]]s) and the high frequency drivers ([[tweeter]]s). The nature of the drivers on both sides of the mid-range, and the mid-range itself, affects the selection of crossover frequency and slope. Nearly all crossovers are passive circuits, designed to match the characteristics of the drivers and their mounting, and are built of capacitors, inductors, and resistors. Active or 'electronic' crossovers are used in some high-performance hi-fi speakers, and in professional [[sound reinforcement system]]s.
Placement of the mid-range (and tweeter) drivers on the enclosure baffle significantly affects the output of the driver, and the material surrounding the mid-range and tweeter drivers on the baffle can produce (or inhibit) reflections of energy from the baffle face, or other items, further influencing the output. Grilles, especially those with structural frames, can further modify the output of the entire speaker system. One of the terms used in design circles to describe some of these diffraction and reflection artifacts is the ''baffle step'' effect.
When a mid-range speaker is mounted in the same box as a woofer, it will have its own small sub-enclosure, or a sealed back, to prevent the woofer's backwave radiation into the box from affecting the mid-range's cone or dome motion.
==See also== * [[Loudspeaker]] * [[Loudspeaker enclosure]] * [[Audio crossover]] * [[Full-range speaker]] * [[Tweeter]] * [[Super tweeter]] * [[Woofer]] * [[Subwoofer]]
==References== {{reflist}}
[[Category:Loudspeakers]]