What is a mid-range speaker?
Mid-range speaker, as its name suggests, covers the middle part of the frequency spectrum. Usually, it covers the range between 500 Hz and 4 kHz. This portion of the audio spectrum may be the most important. This is because it is very audible, and within it, most instruments and the human voice are positioned. On top of that, the human ear is most sensitive to mid-range frequency. Therefore the driver can remain on low power, while still providing good sound in terms of quality and volume.
Systems that incorporate both woofer and tweeter drivers usually have mid-range speakers. Reproduction of the midrange frequencies should sound natural and uncolored with excellent detail while avoiding sounding too forward or recessed or excessively bright or dull. If a speaker’s midrange output isn’t clear, spoken dialogue and musical vocals will be unnatural or inaudible. So, it’s of critical importance to nearly every piece of music and home theatre audio content. The nature of the drivers on both sides of the mid-range, and the mid-range itself affect the selection of crossover frequency and slope. Nearly all crossovers are passive circuits and match the characteristics of the drivers and their mounting. They consist of capacitors, inductors, and resistors. High-performance hi-fi speakers and professional sound reinforcement systems usually have active or ‘electronic’ crossovers.
The structure
Mid-range drivers are usually cone types or, less commonly, dome types, or compression horn drivers. The radiating diaphragm of a cone mid-range unit is a truncated cone, with a voice coil along with the spider portion of the suspension, and with the cone surround at the wide end. Cone mid-range drivers typically resemble small woofers. The most common mid-range cones material is paper. It is occasionally surface-treated with polymers or resins in order to improve vibrational damping.
Other mid-range cone materials include plastics such as polypropylene, Codex, Bextrene, woven Kevlar, fiberglass, carbon fibre, or light metal alloys 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. Its material is 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 drivers with horns. A very few mid-ranges are electrostatic drivers, planar magnetic drivers, or ribbon drivers.
Most television sets and small radios have only a single mid-range driver, or two for stereo sound. Since in the case of television, the most important aspect is talking, it works out well. Since the ear is most sensitive to the middle frequencies, the driver and amplifier can both be low power, while still delivering a good sound both in terms of volume and quality.
Source texts
https://en.wikipedia.org/wiki/Mid-range_speaker?fbclid=IwAR2asZAZpkIm96y89frvxZnY8-EifEVv0lKsYqR4XTSkyi_keyfZcA-Vj5E
