A subwoofer 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. The typical frequency range for 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 that are audible. This very low-frequency (VLF) range reproduces the natural fundamental tones of the bass drum, electric bass, double bass viol, cello, grand piano, contra bassoon, tuba, and organ, in addition to thunder and explosions.
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.
Audio crossovers are a type of electronic filter circuitry that splits an 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. The crossover filters can be either active or passive. They are often described as two-way or three-way, which indicate, respectively, that the crossover splits a given signal into two frequency ranges or three frequency ranges. Crossovers are used in loudspeaker cabinets, power amplifiers in consumer electronics and pro audio and musical instrument amplifier products. For the latter two markets, crossovers are used in bass amplifiers, keyboard amplifiers, bass and keyboard speaker enclosures and sound reinforcement system equipment.
An audiophile is a person who is enthusiastic about high-fidelity sound reproduction. An audiophile seeks to reproduce the sound of a piece of recorded music or a live musical performance, typically inside closed headphones, In-ear monitors, open headphones in a quiet listening space, or a room with good acoustics.
A tweeter or treble speaker is a special type of loudspeaker that is designed to produce high audio frequencies, typically deliver high frequencies up to 100 kHz. 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).
A mid-range speaker is a loudspeaker driver that reproduces sound in the frequency range from 250 to 2000 Hz.
A woofer or bass speaker is a 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". The most common design for a woofer is the electrodynamic driver, which typically uses a stiff paper cone, driven by a voice coil surrounded by a magnetic field.
Audio system measurements are a means of quantifying system performance. These measurements are made for several purposes. Designers take measurements so that they can specify the performance of a piece of equipment. Maintenance engineers make them to ensure equipment is still working to specification, or to ensure that the cumulative defects of an audio path are within limits considered acceptable. Audio system measurements often accommodate psychoacoustic principles to measure the system in a way that relates to human hearing.
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.
A full-range loudspeaker drive unit is defined as a driver which reproduces as much of the audible frequency range as possible, within the limitations imposed by the physical constraints of a specific design. The frequency range of these drivers is maximized through the use of a whizzer cone and other means. Most single driver systems, such as those in radios, or small computer speaker designs, cannot reproduce all of the audible frequencies or the entire audible audio range.
A loudspeaker enclosure or loudspeaker cabinet is an enclosure in which speaker drivers and associated electronic hardware, such as crossover circuits and, in some cases, power amplifiers, are mounted. Enclosures may range in design from simple, homemade DIY rectangular particleboard boxes to very complex, expensive computer-designed hi-fi cabinets that incorporate composite materials, internal baffles, horns, bass reflex ports and acoustic insulation. Loudspeaker enclosures range in size from small "bookshelf" speaker cabinets with 4-inch (10 cm) woofers and small tweeters designed for listening to music with a hi-fi system in a private home to huge, heavy subwoofer enclosures with multiple 18-inch (46 cm) or even 21-inch (53 cm) speakers in huge enclosures which are designed for use in stadium concert sound reinforcement systems for rock music concerts.
Studio monitors are loudspeakers in speaker enclosures specifically designed for professional audio production applications, such as recording studios, filmmaking, television studios, radio studios and project or home studios, where accurate audio reproduction is crucial. Among audio engineers, the term monitor implies that the speaker is designed to produce relatively flat (linear) phase and frequency responses. In other words, it exhibits minimal emphasis or de-emphasis of particular frequencies, the loudspeaker gives an accurate reproduction of the tonal qualities of the source audio, and there will be no relative phase shift of particular frequencies—meaning no distortion in sound-stage perspective for stereo recordings. Beyond stereo sound-stage requirements, a linear phase response helps impulse response remain true to source without encountering "smearing". An unqualified reference to a monitor often refers to a near-field design. This is a speaker small enough to sit on a stand or desk in proximity to the listener, so that most of the sound that the listener hears is coming directly from the speaker, rather than reflecting off walls and ceilings. Monitor speakers may include more than one type of driver or, for monitoring low-frequency sounds, such as bass drum, additional subwoofer cabinets may be used.
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.
Plasma speakers or ionophones are a form of loudspeaker which varies air pressure via an electrical plasma instead of a solid diaphragm. The plasma arc heats the surrounding air causing it to expand. Varying the electrical signal that drives the plasma and connected to the output of an audio amplifier, the plasma size varies which in turn varies the expansion of the surrounding air creating sound waves.
Acoustic suspension is a method of loudspeaker cabinet design and utilisation that uses one or more loudspeaker drivers mounted in a sealed box or cabinet. Acoustic suspension systems reduce bass distortion that can be caused by stiff motor suspensions in conventional loudspeakers.
HD77 is a model name of Marantz 4-way high-fidelity loudspeakers which were produced during the mid-1970s. They were bass reflex speakers, but came with a cylindrical piece of foam which fit into the bass-reflex port of the enclosure if the listener preferred the more accurate bass response provided by airtight speaker boxes. However, they were not fully airtight this way, but rather what is known as aperiodic. They were designed by former JBL Engineer Edmond May. The foam plug in port was in fact a "closed-cell" type which did in fact seal cabinet completely. How it worked was it was cut slightly larger than opening and when inserted, you turned the retainer screw and it would tighten and compress the plug, thereby sealing the cabinet to make the loudspeaker a "suspension" type. The controls on baffle are resistive potentiometers, which changed the response curve of corresponding driver from soft to bright, giving great versatility to adapt within almost any listening environment.
An electrodynamic speaker driver, often called simply a speaker driver when the type is implicit, is an individual transducer that converts an electrical audio signal to sound waves. While the term is sometimes used interchangeably with the term speaker (loudspeaker), it is usually applied to specialized transducers which reproduce only a portion of the audible frequency range. For high fidelity reproduction of sound, multiple loudspeakers are often mounted in the same enclosure, each reproducing a different part of the audible frequency range. In this case the individual speakers are referred to as drivers and the entire unit is called a 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. Less common types of drivers are supertweeters and rotary woofers.
Loudspeaker time-alignment usually simply referred to as "time-alignment" or "Time-Align" is a term applied in loudspeaker systems which use multiple drivers to cover a wide audio range. It involves delaying the sound emanating from one or more drivers to correct the transient response, improve accuracy and, in non-coaxial drivers, improve the directivity or lobe tilting at the crossover frequencies. It employs adjusting the front-to back spacing of the individual drivers so that the sound output is truly simultaneous.
Monitor Audio is a British company that specialises in designing and manufacturing loudspeakers and sound systems.
