Cross section of a standard loudspeaker, not to scale
Two P-Audio Woofers. Note the cast frame, vented pole piece and reinforced paper cone.

Technical term for a loudspeaker driver designed to produce low frequency sounds, typically from 50 Hz up to 1000 Hz. The name is from the onomatopoeic English word for a dog's bark, "woof" .

- Woofer

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Special type of loudspeaker that is designed to produce high audio frequencies, typically deliver high frequencies up to 100 kHz.

Cutaway view of a dynamic tweeter with acoustic lens and a dome-shaped membrane.
Polycell tweeter from an Infinity speaker, showing the components.
Ohm CAM 16 speaker with "egg tweeter".
The cone tweeter from a Marantz 5G loudspeaker
A Philips ribbon tweeter.
A Shackman MHT85 Electrostatic Tweeter.

The name is derived from the high pitched sounds made by some birds (Tweets), especially in contrast to the low woofs made by many dogs, after which low-frequency drivers are named (woofers).


[[File:Electrodynamic-loudspeaker.png|thumb|Hi-fi speaker system for home use with three types of dynamic drivers 1. Mid-range driver

Kellogg and Rice in 1925 holding the large driver of the first moving-coil cone loudspeaker
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.
Exploded view of a dome tweeter
Electronic symbol for a speaker
A passive crossover
A bi-amplified system with an active crossover
An unusual three-way speaker system. The cabinet is narrow to raise the frequency where a diffraction effect called the "baffle step" occurs.
A three-way loudspeaker that uses horns in front of each of the three drivers: a shallow horn for the tweeter, a long, straight horn for mid frequencies and a folded horn for the woofer
Two-way binding posts on a loudspeaker, connected using banana plugs.
A 4-ohm loudspeaker with two pairs of binding posts capable of accepting bi-wiring after the removal of two metal straps.
HP Roar Wireless Speaker
Specifications label on a loudspeaker
Polar plots of a four-driver industrial columnar public address loudspeaker taken at six frequencies. Note how the pattern is nearly omnidirectional at low frequencies, converging to a wide fan-shaped pattern at 1 kHz, then separating into lobes and getting weaker at higher frequencies
Moving iron speaker
A piezoelectric buzzer. The white ceramic piezoelectric material can be seen fixed to a metal diaphragm.
Magnetostatic loudspeaker
Schematic showing an electrostatic speaker's construction and its connections. The thickness of the diaphragm and grids has been exaggerated for the purpose of illustration.
In Heil's air motion transducer, current through the membrane 2 causes it to move left and right in magnetic field 6, moving air in and out along directions 8; barriers 4 prevent air from moving in unintended directions.
Plasma speaker

The smaller drivers capable of reproducing the highest audio frequencies are called tweeters, those for middle frequencies are called mid-range drivers and those for low frequencies are called woofers.

Electrodynamic speaker driver

[[File:Electrodynamic-loudspeaker.png|thumb|Loudspeaker for home use with three types of dynamic drivers 1. Mid-range driver

Woofer speaker drivers
Cut-away view of a dynamic loudspeaker

Drivers made for reproducing high audio frequencies are called tweeters, those for middle frequencies are called mid-range drivers, and those for low frequencies are called woofers, while those for very low bass range are subwoofers.

Audio crossover

Audio signal into two or more frequency ranges, so that the signals can be sent to loudspeaker drivers that are designed to operate within different frequency ranges.

A passive 2-way crossover designed to operate at loudspeaker voltages.
Comparison of the magnitude response of 2 pole Butterworth and Linkwitz-Riley crossover filters. The summed output of the Butterworth filters has a +3dB peak at the crossover frequency.
A passive crossover circuit is often mounted in a speaker enclosure to split up the amplified signal into a lower-frequency signal range and a higher-frequency signal range.
Implementation schematic of a three-way active crossover network for use with a stereo three-way loudspeaker system.
Typical usage of an active crossover, though a passive crossover can be positioned similarly before the amplifiers.
Fourth-order crossover slopes shown on a Smaart transfer function measurement.
Series and parallel crossover topologies. The HPF and LPF sections for the series crossover are interchanged with respect to the parallel crossover since they appear in shunt with the low- and high-frequency drivers.

A standard simple example is in hi-fi and PA system cabinets that contain a woofer for low and mid frequencies and a tweeter for high frequencies.


12-inch (30 cm) subwoofer driver (loudspeaker). A driver is commonly installed in an enclosure (often a wooden cabinet) to prevent the sound waves coming off the back of the driver diaphragm from canceling out the sound waves being generated from the front of the subwoofer.
View of the underside of the downward-firing Infinity Servo Statik 1, showing the size of the 18-inch (45 cm) custom-wound Cerwin-Vega driver in relation to a can of Diet Coke, to show scale.
A display of Cerwin-Vega speaker enclosures at the 1975 Audio Engineering Society meeting.
A crew sets up a sound system, including large bass bins, in Jamaica in 2009.
The 1987 Bose Acoustimass 5 stereo bass driver contained one six-inch (152 mm) driver per channel and provided crossover filtering for its two cube speaker arrays.
Cross-section of a subwoofer drive unit.
Bass reflex enclosure schematic (cross-section).
Heavily braced and built subwoofer enclosure.
A large subwoofer cabinet used in a home hi-fi system.
This picture of the internal components of an active (powered) subwoofer shows the circuitry for the power amplifier.
This rear panel of a powered subwoofer shows the heat sinks used to cool the power amplifier.
This picture of the rear panel of a Polk subwoofer cabinet shows a low-pass filter adjustment knob.
The rear panel of a down-firing, active subwoofer cabinet.
Basic sealed subwoofer in a residential setting.
A small subwoofer cabinet designed for use with a home computer.
Multiple subwoofers in a hatchback car.
Each stack of speakers in this sound reinforcement setup consists of two EAW SB1000 slanted baffle subwoofers (each contains two 18-inch drivers) and two EAW KF850 full range cabinets for the mid and high frequencies.
A row of subwoofer cabinets in front of the stage of a rock concert. One enclosure out of every stack of three is turned backward to make a cardioid output pattern.
Large subwoofer enclosures.
Cardioid dispersion pattern of two end-fire subwoofers placed one in front of the other. The signal feeding the enclosure nearest the listener is delayed by a few milliseconds.
CSA: Six subwoofers arranged for less bass energy on stage. Signal going to the reversed enclosures is delayed a few milliseconds.
End-fire array using three rows of subwoofers. Each row is delayed a few milliseconds more than the previous row.
Compound or 4th order band-pass enclosure

A subwoofer (or sub) is a loudspeaker designed to reproduce low-pitched audio frequencies known as bass and sub-bass, lower in frequency than those which can be (optimally) generated by a woofer.

Loudspeaker enclosure

Enclosure in which speaker drivers (e.g., loudspeakers and tweeters) and associated electronic hardware, such as crossover circuits and, in some cases, power amplifiers, are mounted.

MTX Audio loudspeaker enclosures (with rear panel reflex port tubes) which can mount 15 inch woofers, mid-range drivers and horn and/or compression tweeters. In this photo, only one driver is mounted.
A cabinet with loudspeakers mounted in the holes. Number 1 is a mid-range driver. Number 2 is a high-range driver. Number 3 indicates two low-frequency woofers. Below the bottom woofer is a bass reflex port.
A Lansing Iconic multicell horn loudspeaker from 1937.
Medium density fiberboard is a mediocre material out of which loudspeaker enclosures are built.
A small "bookshelf speaker", an LS3/5A, with its protective grille cover removed.
A box stuffed with fiberglass insulation to increase the effective volume of the box.
A closed-box loudspeaker enclosure.
Isobaric loudspeaker in a cone-to-magnet (in-phase) arrangement. The image above shows a sealed enclosure; vented enclosures may also use the isobaric scheme.
Bass reflex enclosure.
RCA shelf stereo bass reflex multi-way speakers.
Passive radiator enclosure.
Compound or 4th-order band-pass enclosure.
Dipole speakers and their radiation pattern.
Horn loudspeaker schematic.
Multiple entry horn.
Transmission line enclosure.

Enclosures used for woofers and subwoofers can be adequately modeled in the low-frequency region (approximately 100–200 Hz and below) using acoustics and the lumped component models.

Mid-range speaker

Loudspeaker driver that reproduces sound in the frequency range from 250 to 2000 Hz.

Cutaway view of a dynamic mid-range speaker

Cone mid-range drivers typically resemble small woofers.

Veritone Minimum Phase Speakers

Loudspeaker manufacturer founded in 1977 by speaker designer Brian Cheney.

Woofers were used for bass and mid-bass, along with a passive radiator or port for the 626 bookshelf model.

Keyboard amplifier

Powered electronic amplifier and loudspeaker in a wooden speaker cabinet used for amplification of electronic keyboard instruments.

A small, inexpensive keyboard amplifier for personal home use
A US Navy keyboardist playing his Yamaha keyboard through a large Roland keyboard amp.
A tiny BOSS micro-cube keyboard amp being used with a MIDI keyboard.
A keyboardist playing a live show with a big Leslie cabinet (visible to his right).
A keyboardist using a Trace Elliot bass amplifier combo for her onstage sound.

The Leslie creates these effects by rotating the tweeters or horns or a spinning a sound-directing duct around the bass woofer speaker, which causes the Doppler effect.

Josef Anton Hofmann

London-born American audio engineer and speaker-system designer.

A KLH Model Eight radio

Hofmann theorized that when woofers are mounted in speaker enclosures, the designer would have to accept that there are three trade-offs.