Horn loudspeaker with a sealed box driver mounting A horn speaker is a loudspeaker which uses a horn to increase the overall efficiency of the driving element, typically a diaphragm driven by an electromagnet. The horn itself is a passive component and does not amplify the sound from the driving element as such, but rather improves 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 (typically made of paper or, more recently, more exotic materials such as aluminum, titanium, or mylar) and the air (which has a very low density). Image File history File links Horn_speaker. ...
Image File history File links Horn_speaker. ...
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A horn is a tapered sound-guide designed to provide an acoustic impedance match between a sound-producing device and the characteristic impedance of free space. ...
Three-phase pole-mounted step-down transformer. ...
The acoustic impedance Z (or sound impedance) is the ratio of sound pressure p to particle velocity v in a medium or acoustic component. ...
Impedance matching is the practice of attempting to make the output impedance of a source equal to the input impedance of the load to which it is ultimately connected, usually in order to maximize the power transfer and minimize reflections from the load. ...
Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ...
General Name, Symbol, Number titanium, Ti, 22 Chemical series transition metals Group, Period, Block 4, 4, d Appearance silvery metallic Standard atomic weight 47. ...
Mylar is a trade name of DuPont Teijin Films of Hopewell, VA, United States, for biaxially-oriented polyethylene terephthalate (BOPET) polyester film used for its high tensile strength, chemical and dimensional stability, transparency, and electrical insulation. ...
In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: Ï (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is...
This is important because the difference in densities and motional characteristics of the air and of the driving element is a mismatch. The part of the horn next to the speaker cone "driver" is called the "throat" and the large part farthest away from the speaker cone is called the "mouth".
Operation
 Photograph of the original painting of Nipper looking into an Edison Bell cylinder phonograph with a horn speaker. Acoustic horns convert large pressure variations with a small displacement into a low pressure variation with a large displacement and vice versa. It does this through the gradual, often exponential increase of the cross sectional area of the horn. The small cross-sectional area of the throat restricts the passage of air thus presenting a high impedance to the driver. This allows the driver to develop a high pressure for a given displacement. Therefore the sound waves at the throat are of high pressure and low displacement. The tapered shape of the horn allows the sound waves to gradually decompress (and therefore increase in displacement) until they reach the mouth, where they are of a low pressure but large displacement. Image File history File links OriginalNipper. ...
Image File history File links OriginalNipper. ...
Photograph of the original painting of Nipper looking into an Edison Bell cylinder phonograph. ...
Edison cylinder phonograph ca. ...
The term exponential may refer to any of several topics in mathematics: Exponential distribution Exponential function Exponential growth, exponential decay Exponential time Matrix exponential Exponential map (in differential geometry) All relate in some fashion to exponents. ...
The most well known early horn speakers are those on mechanical phonographs, where the record moves a heavy metal needle that excites vibrations in a small metal diaphragm that acts as the driver for a horn. A famous example is the horn through which Nipper the RCA dog hears "His Master's Voice". The horn improves the loading and thus gets a better "coupling" of energy from the diaphragm into the air, and the pressure variations therefore get smaller as the volume expands and the sound travels up the horn. Edison cylinder phonograph ca. ...
In a loudspeaker, a diaphragm is the thin, semi-rigid membrane attached to the central magnet. ...
RCA, formerly an initialism for the Radio Corporation of America, is now a trademark owned by RCA Trademark Management S.A. [1], owned by Thomson SA. The trademark is used by two companies for products descended from that common ancestor: Thomson SA, which manufactures consumer electronics like RCA-branded televisions...
A modern electrically driven horn speaker works the same way, replacing the mechanically excited diaphragm with a dynamic or piezoelectric speaker. Piezoelectricity is the ability of certain crystals to produce a voltage when subjected to mechanical stress. ...
Improvements on basic designs The physics (and mathematics) of horn operation were developed for many years, reaching considerable sophistication before WWII.
As a cone shape of fixed length would resonate at the natural frequency of its length, modern horn designs typically feature some form of exponential flare, such as the tractrix taper. Roughly speaking, the slower the flare rate, the deeper and lower frequencies the horn will reproduce for a given length of horn. For example, a horn area growth rate of 30% per foot will allow reproduction down to about 30 Hz; 1000% per foot (10 times area) per foot provides midrange reproduction; 100 times area per foot is used in high frequency horns. This article is about the geometric object, for other uses see Cone. ...
This article is about resonance in physics. ...
It has been suggested that Tractrice be merged into this article or section. ...
In cymbal making, taper refers to the gradual change in thickness from the bell to the rim of the cymbal. ...
The hertz (symbol: Hz) is the SI unit of frequency. ...
Modern high output horns also make the throat area of the horn smaller than the cone diaphram area. This is called the "loading" or "compression" ratio of the horn. The compression ratio is the cone area divided by the throat area. Typically for bass and midrange frequency the compression ratio is from (1.5 to 1) low compression to normal compression (2 to 1) to high compression (3.5 to 1). High frequency tweeters sometimes have compression ratios as high as 10 to 1.
The higher the compression the greater the horn's ability to properly couple the diaphragm to the air at the horn's mouth, increasing efficiency, until the compression ratio is so high that it actually begins to impede cone motion. At this point the maximum sound output power from the horn (at a given distortion) will be reduced. To demonstrate this at an extreme, place a cone woofer face down on a concrete floor. The compression ratio will be very high, however sound output from the back of the speaker will be quite low.
Applications Horn speakers are used in many audio applications, since use of a horn reduces the need for exotic speaker cone materials and construction, eg, to be as lightweight and rigid as possible. The drivers in horn speakers can be very small, even for bass frequencies where conventional speakers would need to be very large for equivalent performance. Horn speakers can be designed to reproduce a wide range of frequencies using a single, small driver; to some extent these designs avoid the need for a crossover entirely. Lowther, Fostex, and Goodmans are firms which have produced such speakers. FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ...
Audio crossovers are a class of electronic filters designed specifically for use in audio applications, especially hi-fi. ...
Horn speakers can provide very high efficiencies, making them a good match for very low-powered amplifiers, such as single-ended triode amps or other tube amplifiers. After WWII, some early hi-fi fans went so far as to build low frequency horns whose mouths took up much of a wall of the listening room. The throats were sometimes outside on the lawn, or in the basement. With the coming of stereo in the 1960s, this approach became impossible even for the most dedicated fans. those with domestic appearance concerns had never been able to use such large constructions in any case. Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ...
In a single-ended triode (SET) electronic amplifier the entire audio signal waveform is amplified by the triode. ...
Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ...
Some audiophiles use horn speakers for audio reproduction, while others eschew horn systems for their harmonic resonances (finding them an unpleasant form of distortion). Since there are a variety of horn designs (of differing length, material, and taper, as well as different drivers) it is, to some extent, impossible to give such blanket characterizations to horn speakers generally. An audiophile, from Latin audire[1] to hear and Greek philos[2] loving, can be generally defined as a person dedicated to achieving high fidelity in the recording and playback of music . ...
A distortion is the alteration of the original shape (or other characteristic) of an object, image, sound, waveform or other form of information or representation. ...
Public address and concert use Horn speakers can also be used to provide the very high sound pressure levels needed for sound reinforcement and public address applications, although in these high sound pressure applications, high fidelity is sometimes compromised for the sake of the necessary efficiency, and also for the controlled dispersion characteristics which are generally required in most large volume spaces. Concert venues often use large arrays of horn speakers for high-volume bass reproduction ("bass bins"), in order to provide bass that concertgoers can not only hear but also feel. For the financial services company, see Fidelity Investments. ...
See also The horn (popularly known also as the French horn) is a brass instrument decended from the natural horn that consists of tubing wrapped into a coiled form. ...
An old Altec Lansing PC speaker. ...
Klipsch Audio Technologies is one of the most successful consumer and professional speaker companies in America. ...
External links - Single Driver Website: Horn Design
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