A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies, known as bass and sub-bass, that are lower in frequency than those which can be (optimally) generated by a woofer. The typical frequency range that is covered by a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below 80 Hz in THX-certified systems. Thus, one or more subwoofers are important for high-quality sound reproduction as they are responsible for the lowest two to three octaves of the ten octaves that are audible. This very low-frequency (VLF) range reproduces the natural fundamental tones of the bass drum, electric bass, double bass, grand piano, contrabassoon, tuba, in addition to thunder, gunshots, explosions, etc.
A loudspeaker is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A speaker system, also often simply referred to as a speaker or loudspeaker, comprises one or more such speaker drivers, an enclosure, and electrical connections possibly including a crossover network. The speaker driver can be viewed as a linear motor attached to a diaphragm which couples that motor's movement to motion of air, that is, sound. An audio signal, typically from a microphone, recording, or radio broadcast, is amplified electronically to a power level capable of driving that motor in order to reproduce the sound corresponding to the original unamplified electronic signal. This is thus the opposite function to the microphone; indeed the dynamic speaker driver, by far the most common type, is a linear motor in the same basic configuration as the dynamic microphone which uses such a motor in reverse, as a generator.
A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers in enclosures all controlled by a mixing console that makes live or pre-recorded sounds louder and may also distribute those sounds to a larger or more distant audience. In many situations, a sound reinforcement system is also used to enhance or alter the sound of the sources on the stage, typically by using electronic effects, such as reverb, as opposed to simply amplifying the sources unaltered.
A horn loudspeaker is a loudspeaker or loudspeaker element which uses an acoustic horn to increase the overall efficiency of the driving element(s). A common form (right) consists of a compression driver which produces sound waves with a small metal diaphragm vibrated by an electromagnet, attached to a horn, a flaring duct to conduct the sound waves to the open air. Another type is a woofer driver mounted in a loudspeaker enclosure which is divided by internal partitions to form a zigzag flaring duct which functions as a horn; this type is called a folded horn speaker. The horn serves to improve the coupling efficiency between the speaker driver and the air. The horn can be thought of as an "acoustic transformer" that provides impedance matching between the relatively dense diaphragm material and the less-dense air. The result is greater acoustic output power from a given driver.
Klipsch Audio Technologies is an American loudspeaker company based in Indianapolis, Indiana. Founded in Hope, Arkansas, in 1946 as 'Klipsch and Associates' by Paul W. Klipsch, the company produces loudspeaker drivers and enclosures, as well as complete loudspeakers for high-end, high-fidelity sound systems, public address applications, and personal computers.
JBL is an American audio equipment manufacturer headquartered in Los Angeles, California, United States. JBL serves the customer home and professional market. The professional market includes studios, installed/tour/portable sound, music production, DJ, cinema markets. The home market includes high-end home amplification/speakers/headphones as well as high-end car audio. JBL is owned by Harman International, itself a subsidiary of Samsung Electronics.
Altec Lansing, Inc. is an American audio electronics company founded in 1927. Their primary products are loudspeakers and associated audio electronics for professional, home, automotive and multimedia applications.
MartinLogan (ML) is a Canadian/US company producing conventional subwoofer speakers as well as floor-standing, wall-mounted, and in-wall hybrid speakers using electrostatic loudspeaker and planar magnetic thin film loudspeaker technology.
Celestion is a British designer and exporter of professional loudspeakers.
The Air Motion Transformer (AMT) is a type of electroacoustic transducer. Invented by Oskar Heil (1908–1994), it operates on a different transduction principle from other loudspeaker designs, such as moving coil, planar magnetic or electrostatically-driven loudspeakers, and should not be confused with planar or true ribbon loudspeakers. In contrast to a planar ribbon loudspeaker, the diaphragm of the AMT is of pleated shape similar to a bellows. The AMT moves air laterally in a perpendicular motion using a metal-etched folded sheet made of polyethylene terephthalate (PET) film. The circuit path embossed on the PET membrane, acts as the voice coil unit. The diaphragm is then housed between 4 stacks of steel pole-plate pieces positioned at 45° within a high-intensity, quadratic, opposing magnetic field. The air motion transformer with its sheet film equally exposed at 180° behaves as a dipole speaker, exciting front and rear sonic waves simultaneously.
Meyer Sound Laboratories is an American company based in Berkeley, California that manufactures self-powered loudspeakers, multichannel audio show control systems, electroacoustic architecture, and audio analysis tools for the professional sound reinforcement, fixed installation, and sound recording industries.
A line array is a loudspeaker system that is made up of a number of usually identical loudspeaker elements mounted in a line and fed in phase, to create a near-line source of sound. The distance between adjacent drivers is close enough that they constructively interfere with each other to send sound waves farther than traditional horn-loaded loudspeakers, and with a more evenly distributed sound output pattern.
John Kenneth Hilliard was an American acoustical and electrical engineer who pioneered a number of important loudspeaker concepts and designs. He helped develop the practical use of recording sound for film, and won an Academy Award in 1935. He designed movie theater sound systems, and he worked on radar as well as submarine detection equipment during World War II. Hilliard collaborated with James B. "Jim" Lansing in creating the long-lived Altec Voice of the Theatre speaker system. Hilliard researched high-intensity acoustics, vibration, miniaturization and long-line communications for NASA and the Air Force. Near the end of his career, he standardized noise-control criteria for home construction in California, a pattern since applied to new homes throughout the U.S.
David W. Gunness is an American audio engineer, electrical engineer and inventor. He is known for his work on loudspeaker design, especially high-output professional horn loudspeakers for public address, studio, theater, nightclub, concert and touring uses.
Cliff Henricksen is a musician, inventor and audio technologist. He is self-taught as a musician with a graduate degree in mechanical engineering at Massachusetts Institute of Technology (MIT). Throughout his career Cliff has found innovative ways to apply engineering basics to electro acoustics and to audio technology as it applies to music and in particular to live music performance. He has invented and engineered a wide variety of technologies and products well known in the world of professional audio. Today he balances work in audio and work as a performing musician.
Charles Emory Hughes II is an American inventor and audio engineer. He is known for his work on loudspeaker design, and the measurement of professional audio sound systems. Hughes first worked for Peavey Electronics designing loudspeakers and horns where he was granted a patent for the Quadratic-Throat Waveguide horn used in concert loudspeakers. He worked for Altec Lansing for two years as chief engineer for the pro audio division and was granted two more patents. In 2021, Hughes was hired by Biamp as principal engineer.
D. Broadus Keele Jr., also known simply as Don Keele or D. B. Keele Jr., is an American audio engineer and inventor who has helped shape and influence the professional and consumer loudspeaker industries since the early seventies. He is one of the developers of the constant directivity horn design with several patents of Bi-radial horns from companies like JBL, and Electrovoice.
Thomas J. Danley is an American audio engineer, electrical engineer and inventor, the holder of multiple patents for audio transducers, especially high-linearity, high-output professional horn loudspeaker systems. Danley first gained notice in the 1980s with his novel servomotor-driven subwoofer systems used to reproduce very low frequencies in concert tours and theme parks. In 2000 he advanced the implementation of multiple-entry horns in 2000 with several designs led by the SPL-td1, a seven-driver loudspeaker. In 2005, he started a new company, Danley Sound Labs, through which he patented further technologies and produced a wide variety of loudspeaker models based on these technologies.
Robert Vernon Cavin is an American audio engineer who built the first monitor mixing console, the first multi-angle monitor loudspeaker, and the first integrated processing/amplifier package for a 3-way loudspeaker. He was chief engineer of McCune Sound in San Francisco in the 1970s, and also vice president in the 1980s. In 1992 he accepted the chief engineer position at Apogee Sound where he designed the DA Series Class-H digitally controlled amplifier, winning the 1994 TCI Product of the Year Award. In 2000 he joined Furman Sound, and designed an interface system for Smaart users, and a new power conditioning system. Cavin's electronic designs were nominated five times for TEC Awards, in 1994, 1995, 1997, 1999 and 2001.
Ronald M. Aarts,, is a Dutch electrical engineer and physicist, inventor and professor in the field of electroacoustics and in biomedical signal processing technology.
