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Loudspeaker Measurement
A loudspeaker (commonly referred to as a speaker or, more fully, a speaker system) is a combination of one or more speaker drivers, an enclosure, and electrical connections (possibly including a crossover network). The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. The driver is a linear motor connected to a diaphragm, which transmits the motor's movement to produce sound by moving air. An audio signal, typically originating from a microphone, recording, or radio broadcast, is electronically amplified to a power level sufficient to drive the motor, reproducing the sound corresponding to the original unamplified signal. This process functions as the inverse of a microphone. In fact, the ''dynamic speaker'' driver—the most common type—shares the same basic configuration as a dynamic microphone, which operates in reverse as a generator. The dynamic speaker was invented in 1925 by Edward W. Kellogg an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permanent Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called Ferromagnetism, ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth element, rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Receiver
In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna intercepts radio waves (electromagnetic waves of radio frequency) and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information. The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation. Radio receivers are essential components of all systems based on radio technology. The information produced by the receiver may be in the form of sound, video (television), or digital data. A radio receiver may be a separate piece of electronic equ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powered Speaker
Powered speakers, also known as self-powered speakers and active speakers, are loudspeakers that have built-in amplifiers. Powered speakers are used in a range of settings, including in sound reinforcement systems (used at live music concerts), both for the main speakers facing the audience and the monitor speakers facing the performers; by DJs performing at dance events and raves; in private homes as part of hi-fi or home cinema audio systems and as computer speakers. They can be connected directly to a mixing console or other low-level audio signal source without the need for an external amplifier. Some active speakers designed for sound reinforcement system use have an onboard mixing console and microphone preamplifier, which enables microphones to be connected directly to the speaker. Active speakers have several advantages, the most obvious being their compactness and simplicity. Additionally the amplifier(s) can be designed to closely match the optimal requirements of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossover Network
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 (hi-fi, home cinema sound and car audio) 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 (PA speakers, monitor speakers, subwoofer systems, etc.). Crossovers are used because most individual loudspeaker drivers are incapable of covering the ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woofer
A woofer or bass speaker is a technical term for a loudspeaker driver designed to produce low frequency sounds, typically from 50 up to 200 Hz. The name is from the onomatopoeic English word for a dog's deep bark, " woof" (in contrast to a '' tweeter'', the name used for loudspeakers designed to reproduce high-frequency sounds, deriving from the shrill calls of birds, " tweets"). 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. The voice coil is attached by adhesives to the back of the loudspeaker cone. The voice coil and the magnet form a linear electric motor. When current flows through the voice coil, the coil moves in relation to the frame according to Fleming's left hand rule for motors, causing the coil to push or pull on the driver cone in a piston-like way. The resulting motion of the cone creates sound waves, as it moves in and out. At ordinary sound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-range Speaker
A mid-range speaker is a loudspeaker driver that reproduces sound in the frequency range from 200 to 2,000 Hz. 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 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 woofers. The most common material used for mid-range cones is paper, occasionally impregnated and/or surface-treated with polymers or resins 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 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, made from cloth, metal, or plastic film, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tweeter
A tweeter or treble speaker is a special type of loudspeaker (usually dome, inverse dome or horn-type) that is designed to produce high audio frequencies, typically from 2,000 to 20,000 Hertz, Hz. 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). Operation Nearly all tweeters are electrodynamic drivers using a voice coil suspended within a fixed magnetic field. These designs operate by applying current from the output of an amplifier circuit to a coil of wire called a voice coil. The voice coil produces a varying magnetic field, which works against the fixed magnetic field of a permanent magnet around which the cylindrical voice coil is suspended, forcing the voice coil and the diaphragm attached to it to move. This mechanical movement resembles the waveform of the electronic signal supplied from the amplifier's output to the voice co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Frequency
An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. The generally accepted standard hearing range for humans is 20 to 20,000 Hz (20 kHz). In air at atmospheric pressure, these represent sound waves with wavelengths of to . Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Sound waves that have frequencies below 20 Hz are called infrasonic and those above 20 kHz are called ultrasonic. Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances. In general, frequency components of a sound determine its "color", its timbre. When speaking about the frequency (in singular) of a sound, it means the property that most determines its pitch. Higher pitches have higher frequency, and low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Fidelity
High fidelity (hi-fi or, rarely, HiFi) is the high-quality reproduction of sound. It is popular with audiophiles and home audio enthusiasts. Ideally, high-fidelity equipment has inaudible noise and distortion, and a flat (neutral, uncolored) frequency response within the human hearing range. High fidelity contrasts with the lower-quality " lo-fi" sound produced by inexpensive audio equipment, AM radio, or the inferior quality of sound reproduction that can be heard in recordings made until the late 1940s. History Bell Laboratories began experimenting with various recording techniques in the early 1930s. Performances by Leopold Stokowski and the Philadelphia Orchestra were recorded in 1931 and 1932 using telephone lines between the Academy of Music in Philadelphia and the Bell labs in New Jersey. Some multitrack recordings were made on optical sound film, which led to new advances used primarily by MGM (as early as 1937) and Twentieth Century Fox Film Corporation (as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speaker Enclosure
A loudspeaker enclosure or loudspeaker cabinet is an enclosure (often rectangular box-shaped) in which speaker drivers (e.g., woofers and tweeters) and associated electronic hardware, such as Audio crossover, 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, bass reflex ports and acoustic insulation. Loudspeaker enclosures range in size from small Bookshelf speaker, "bookshelf" speaker cabinets with 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 or even speakers in huge enclosures which are designed for use in stadium concert sound reinforcement systems for rock music concerts. The primary role of an enclosure is to prevent sound waves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Baffle
A sound baffle is a construction or device which reduces the strength (level) of airborne sound. Sound baffles are a fundamental tool of noise mitigation, the practice of minimizing noise pollution or reverberation. An important type of sound baffle is the noise barrier constructed along highways to reduce sound levels in the vicinity of properties. Sound baffles are also applied to walls and ceilings in building interiors to absorb sound energy and thus lessen reverberation. Highway noise barriers The technology for accurate prediction of the effects of noise barrier design using a computer model to analyze roadway noise has been available since the early 1970s. The earliest published scientific design of a noise barrier may have occurred in Santa Clara County, California in 1970 for a section of the Foothill Expressway in Los Altos, California. The county used a computer model to predict the effects of sound propagation from roadways, with variables consisting of vehicle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
