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Tonewheel
A tonewheel or tone wheel is a simple electromechanical apparatus used for generating electric musical notes in electromechanical organ instruments such as the Hammond Organ and in telephony to generate audible signals such as Ringing tone. It was developed by Thaddeus Cahill for the telharmonium c. 1896 and patented in 1897. It was reinvented around 1910 by Rudolph Goldschmidt for use in pre–vacuum-tube radio receivers as a beat frequency oscillator (BFO) to make continuous wave radiotelegraphy (Morse code) signals audible. Description The tonewheel assembly consists of a synchronous AC motor and an associated gearbox that drives a series of rotating disks. Each disk has a given number of smooth bumps at the rim; these generate a specific frequency as the disk rotates close to a pickup assembly that consists of a magnet and electromagnetic coil. As each bump in the wheel approaches the pickup, it temporarily concentrates the magnetic field near it, and thus strengthens th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammond Organ
The Hammond organ is an electric organ invented by Laurens Hammond and John M. Hanert and first manufactured in 1935. Multiple models have been produced, most of which use sliding drawbars to vary sounds. Until 1975, Hammond organs generated sound by creating an electric current from rotating a metal tonewheel near an electromagnetic pickup, and then strengthening the signal with an amplifier to drive a speaker cabinet. The organ is commonly used with the Leslie speaker. Around two million Hammond organs have been manufactured. The organ was originally marketed by the Hammond Organ Company to churches as a lower-cost alternative to the wind-driven pipe organ, or instead of a piano. It quickly became popular with professional jazz musicians in organ trios—small groups centered on the Hammond organ. Jazz club owners found that organ trios were cheaper than hiring a big band. Jimmy Smith's use of the Hammond B-3, with its additional harmonic percussion feature, inspired a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammond Organ
The Hammond organ is an electric organ invented by Laurens Hammond and John M. Hanert and first manufactured in 1935. Multiple models have been produced, most of which use sliding drawbars to vary sounds. Until 1975, Hammond organs generated sound by creating an electric current from rotating a metal tonewheel near an electromagnetic pickup, and then strengthening the signal with an amplifier to drive a speaker cabinet. The organ is commonly used with the Leslie speaker. Around two million Hammond organs have been manufactured. The organ was originally marketed by the Hammond Organ Company to churches as a lower-cost alternative to the wind-driven pipe organ, or instead of a piano. It quickly became popular with professional jazz musicians in organ trios—small groups centered on the Hammond organ. Jazz club owners found that organ trios were cheaper than hiring a big band. Jimmy Smith's use of the Hammond B-3, with its additional harmonic percussion feature, inspired a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Organ
An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since developed into several types of instruments: * Hammond-style organs used in pop, rock and jazz; * digital church organs, which imitate pipe organs and are used primarily in churches; * other types including combo organs, home organs, and software organs. History Predecessors ;Harmonium The immediate predecessor of the electronic organ was the harmonium, or reed organ, an instrument that was common in homes and small churches in the late 19th and early 20th centuries. In a fashion not totally unlike that of pipe organs, reed organs generate sound by forcing air over a set of reeds by means of a bellows, usually operated by constantly pumping a set of pedals. While reed organs have limited tonal quality, they are small, inexpensive, self ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telharmonium
The Telharmonium (also known as the Dynamophone) was an early electrical organ, developed by Thaddeus Cahill c. 1896 and patented in 1897. , filed 1896-02-04. The electrical signal from the Telharmonium was transmitted over wires; it was heard on the receiving end by means of "horn" speakers. An authoritative history of the Telharmonium. Weidenaar produced a 29-minute documentary video, also called (Sewebsitefor extensive additional documentation) Like the later Hammond organ, the Telharmonium used tonewheels to generate musical sounds as electrical signals by additive synthesis. It is considered to be the first electromechanical musical instrument. History Cahill built three versions: The Mark I version weighed 7 tons. The Mark II version weighed almost 210 tons, as did the Mark III. Each was a considerable advancement over the features of its predecessor. A small number of performances in front of a live audience were given in addition to the telephone transmissions. Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telharmonium
The Telharmonium (also known as the Dynamophone) was an early electrical organ, developed by Thaddeus Cahill c. 1896 and patented in 1897. , filed 1896-02-04. The electrical signal from the Telharmonium was transmitted over wires; it was heard on the receiving end by means of "horn" speakers. An authoritative history of the Telharmonium. Weidenaar produced a 29-minute documentary video, also called (Sewebsitefor extensive additional documentation) Like the later Hammond organ, the Telharmonium used tonewheels to generate musical sounds as electrical signals by additive synthesis. It is considered to be the first electromechanical musical instrument. History Cahill built three versions: The Mark I version weighed 7 tons. The Mark II version weighed almost 210 tons, as did the Mark III. Each was a considerable advancement over the features of its predecessor. A small number of performances in front of a live audience were given in addition to the telephone transmissions. Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rudolph Goldschmidt
Rudolf Goldschmidt (1876—1950) was a German engineer and inventor, best known for the development of the Goldschmidt alternator radio transmitter, and the tone wheel receiver. Biography Early life Goldschmidt was born on March 19, 1876 in Neubukow, Mecklenburg, Germany, and grew up in that country. He studied engineering at Charlottenburg and Darmstadt Technical High School, and was awarded an electrical engineer degree at Technische Hochschule Darmstadt in January 1898. Beginning in 1899 he published numerous articles on various branches of electrical engineering. In 1900 he received a college and traveling scholarship, and visited engineering works in Belgium, England, and France. Later that year he was appointed engineer in the laboratory of the Allgemeine Elektricitäts-Gesellschaft AG (AEG) in Berlin. In 1901-1902 he was chief laboratory engineer and designer for Kolben and Company, Ltd., in Prague. He came to England in connection with the Willesden Electricity Supply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Savart Wheel
The Savart wheel is an acoustical device named after the French physicist Félix Savart (1791–1841), which was originally conceived and developed by the English scientist Robert Hooke (1635–1703). A card held to the edge of a spinning toothed wheel will produce a tone whose pitch varies with the speed of the wheel. A mechanism of this sort, made using brass wheels, allowed Hooke to produce sound waves of a known frequency, and to demonstrate to the Royal Society in 1681 how pitch relates to frequency. For practical purposes Hooke's device was soon supplanted by the invention of the tuning fork. About a century and a half after Hooke's work, the mechanism was taken up again by Savart for his investigations into the range of human hearing. In the 1830s Savart was able to construct large, finely-toothed brass wheels producing frequencies of up to 24 kHz that seem to have been the world's first artificial ultrasonic generators. In the later 19th century, Savart's wheels were al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of 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 other substances respond weakly to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guitar Pickup
A pickup is a transducer that captures or senses mechanical vibrations produced by musical instruments, particularly stringed instruments such as the electric guitar, and converts these to an electrical signal that is amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can also be recorded directly. Most electric guitars and electric basses use magnetic pickups. Acoustic guitars, upright basses and fiddles often use a piezoelectric pickup. Magnetic pickups A typical magnetic pickup is a transducer (specifically a variable reluctance sensor) that consists of one or more permanent magnets (usually alnico or ferrite) wrapped with a coil of several thousand turns of fine enameled copper wire. The magnet creates a magnetic field which is focused by the pickup's pole piece or pieces. The permanent magnet in the pickup magnetizes the guitar string above it. This causes the string to generate a mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Induction
Electromagnetic or magnetic induction is the production of an electromotive force (emf) across an electrical conductor in a changing magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday's law of induction. Lenz's law describes the direction of the induced field. Faraday's law was later generalized to become the Maxwell–Faraday equation, one of the four Maxwell equations in his theory of electromagnetism. Electromagnetic induction has found many applications, including electrical components such as inductors and transformers, and devices such as electric motors and generators. History Electromagnetic induction was discovered by Michael Faraday, published in 1831. It was discovered independently by Joseph Henry in 1832. In Faraday's first experimental demonstration (August 29, 1831), he wrapped two wires around opposite sides of an iron ring or "torus" (an arrangement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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