Information about Wireless Microphone
A wireless microphone, as the name implies, is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated.
Various individuals and organisations claim to be the inventors of the Wireless Microphone.
John F. Stephens developed an FM wireless microphone for a Navy musical show in 1951 on the Memphis Naval base. Each of the principal players/singers had their own microphone/transmitter. Subsequently, the Secret Service had Stephens modify his invention to be used in government "bugging" operations. In the '60s, Stephens marketed his more famous capstanless multitrack recorder/reproducers.
Shure Incorporated claim that their "Vagabond" system from 1953 was the first.
In 1957 German audio equipment manufacturer Sennheiser, at that time called Lab W, working with the German broadcaster Norddeutscher Rundfunk (NDR) exhibited a wireless microphone system. From 1958 the system was marketed through Telefunken under the name of Mikroport.
Another German equipment manufacturer, Beyerdynamic, claim that first wireless microphone, was invented by Hung C. Lin. Called the "transistophone", it went into production in 1962. It is claimed that the first time a wireless microphone was used to record sound during filming of a motion picture was on Rex Harrison in the 1964 film My Fair Lady.
More commonly known as a Radio Microphone, there are many different standards, frequencies and transmission technologies used to replace the microphone's cable connection and make it into a wireless microphone. They can transmit, for example, in radiowaves using UHF or VHF frequencies, FM, AM, or various digital modulation schemes. Some low cost models use infrared light. Infrared microphones require a direct line of sight between the microphone and the receiver, while costlier radio frequency models do not.
Some models operate on a single fixed frequency, but the more advanced models operate on a user selectable frequency to avoid interference, and allow the use of several microphones at the same time.
The advantages are:
Another technique used to improve the sound quality (actually, to improve the dynamic range), is companding.
Some models have adjustable gain on the microphone itself, to be able to accommodate different level sources, such as loud instruments or quiet voices. Adjustable gain helps to avoid clipping.
Some models have adjustable squelch, which silences the output when the receiver does not get a strong or quality signal from the microphone, instead of reproducing noise. When squelch is adjusted, the threshold of the signal quality or level is adjusted.
Generally they are two wireless microphone types: handheld and bodypack:
There are three main types of receiver, available in two main types of housing. True Diversity receivers have two radio modules and two antennas. Diversity receivers have one radio module and two antennas. Non-diversity modules have one antenna.
Receivers are commonly housed in a half-rack configuration, so that two can be mounted together in a rack system. For large complex multi channel radio microphone systems, as used in broadcast television studios and musical theatre productions, modular receiver systems with several (commonly eight) true diversity receivers slotting into a rack mounted mainframe housing are available. Several mainframes may be used together in a rack to supply the number of receivers required. In some musical theatre productions, systems with forty or more radio microphones are not unusual.
Receivers specifically for use with video cameras are often mounted in a bodypack configuration, typically with a hotshoe mount to be fitted onto the hotshoe of the camcorder. Small true diversity receivers which slot in to a special housing on many professional broadcast standard video cameras are produced by manufacturers including Sennheiser and Sony. For less demanding or more budget conscious video applications small non-diversity receivers are common. When used at relatively short operating distances from the transmitter this arrangement gives adequate and reliable performance.
In the UK, use of wireless microphone systems requires a licence, except for the licence free bands of 173.8 MHz - 175.0 MHz and 863 MHz - 865 MHz (N.B. This is emphatically NOT TV Channel 69. Channel 69 is from 854 - 862 MHz. In the UK Channel 69 frequencies do require a licence from JFMG Ltd.: [1] ).
The UK communications regulator, Ofcom, has said it will auction part of the spectrum currently reserved for wireless microphones, to which objections have been raised by Andrew Lloyd Webber. [2] [3]
In many other countries wireless microphone use requires a licence. Some governments regard all radio frequencies as military assets and the use of unlicenced radio transmitters, even wireless microphones, may be severely punished.
Spread Spectrum technology can be used to put more wireless microphones in the same RF space.
Manufacturers working with digital wireless microphone technology include Lectrosonics, Sabine, and Zaxcom.
Various individuals and organisations claim to be the inventors of the Wireless Microphone.
John F. Stephens developed an FM wireless microphone for a Navy musical show in 1951 on the Memphis Naval base. Each of the principal players/singers had their own microphone/transmitter. Subsequently, the Secret Service had Stephens modify his invention to be used in government "bugging" operations. In the '60s, Stephens marketed his more famous capstanless multitrack recorder/reproducers.
Shure Incorporated claim that their "Vagabond" system from 1953 was the first.
In 1957 German audio equipment manufacturer Sennheiser, at that time called Lab W, working with the German broadcaster Norddeutscher Rundfunk (NDR) exhibited a wireless microphone system. From 1958 the system was marketed through Telefunken under the name of Mikroport.
Another German equipment manufacturer, Beyerdynamic, claim that first wireless microphone, was invented by Hung C. Lin. Called the "transistophone", it went into production in 1962. It is claimed that the first time a wireless microphone was used to record sound during filming of a motion picture was on Rex Harrison in the 1964 film My Fair Lady.
More commonly known as a Radio Microphone, there are many different standards, frequencies and transmission technologies used to replace the microphone's cable connection and make it into a wireless microphone. They can transmit, for example, in radiowaves using UHF or VHF frequencies, FM, AM, or various digital modulation schemes. Some low cost models use infrared light. Infrared microphones require a direct line of sight between the microphone and the receiver, while costlier radio frequency models do not.
Some models operate on a single fixed frequency, but the more advanced models operate on a user selectable frequency to avoid interference, and allow the use of several microphones at the same time.
Advantages and disadvantages
)
Wireless microphones awaiting pickup by performers in a musical.
- The freedom of movement for the artist or speaker.
- Avoidance of cabling problems that are common on wired microphones, caused by constant moving and stressing the cables.
- Sometimes limited range (a wired balanced XLR microphone can run up to 300 ft or 100 meters). Some wireless systems have a shorter range, while more expensive models can exceed that distance.
- Possible interference with other radio equipment or other microphones, though models with many frequency-synthesized switch-selectable channels are now plentiful and cost effective.
- Limited operation time due to battery life.
- Noise or dead spots (places where it doesn't work, in non-diversity systems)
- Limited number of operating microphones at the same time and place, due to the limited number of radio channels (frequencies).
Techniques
The professional models transmit in VHF or UHF radio frequency and have 'true' diversity reception (two separate receiver modules each with its own antenna), which eliminates dead spots (caused by phase cancellation) and the effects caused by the reflection of the radiowaves on walls and surfaces in general. (See antenna diversity).Another technique used to improve the sound quality (actually, to improve the dynamic range), is companding.
Some models have adjustable gain on the microphone itself, to be able to accommodate different level sources, such as loud instruments or quiet voices. Adjustable gain helps to avoid clipping.
Some models have adjustable squelch, which silences the output when the receiver does not get a strong or quality signal from the microphone, instead of reproducing noise. When squelch is adjusted, the threshold of the signal quality or level is adjusted.
Products
Shure, Sennheiser, Lectrosonics, Samson Technologies, AKG Acoustics and Audio-Technica are all major manufacturers of wireless microphone systems. They have made significant advances in dealing with many of the disadvantages listed above. For example, while there is a limited band in which the microphones may operate, the new UHF-R series from Shure can have up to 108 different microphones operating simultaneously. However, allowing more microphones to operate at the same time increases the cost. That is one reason for such large price differences between different series of wireless systems. The audio quality has also greatly improved as newer systems have become available.Generally they are two wireless microphone types: handheld and bodypack:
- Handheld is like a normal microphone, but it has a bigger body to accommodate the transmitter and battery pack.
- Bodypack is a small box housing the transmitter and battery pack, but not the microphone itself. It is attachable to belt or elsewhere and has a wire going to headset, lavalier microphone or a guitar.
There are three main types of receiver, available in two main types of housing. True Diversity receivers have two radio modules and two antennas. Diversity receivers have one radio module and two antennas. Non-diversity modules have one antenna.
Receivers are commonly housed in a half-rack configuration, so that two can be mounted together in a rack system. For large complex multi channel radio microphone systems, as used in broadcast television studios and musical theatre productions, modular receiver systems with several (commonly eight) true diversity receivers slotting into a rack mounted mainframe housing are available. Several mainframes may be used together in a rack to supply the number of receivers required. In some musical theatre productions, systems with forty or more radio microphones are not unusual.
Receivers specifically for use with video cameras are often mounted in a bodypack configuration, typically with a hotshoe mount to be fitted onto the hotshoe of the camcorder. Small true diversity receivers which slot in to a special housing on many professional broadcast standard video cameras are produced by manufacturers including Sennheiser and Sony. For less demanding or more budget conscious video applications small non-diversity receivers are common. When used at relatively short operating distances from the transmitter this arrangement gives adequate and reliable performance.
Technologies
VHF
The VHF band is located in the frequency range between 30 MHz and 300 MHz. This is the other common band used in wireless microphone systems, but it is not used as commonly as UHF. VHF wireless microphones are typically those of the fixed frequency type, meaning that the user has no opportunity to switch frequencies if interference is encountered.UHF
The UHF band is located in the frequency range between 300 MHz and 3 GHz and is the most common band used in wireless microphone systems. Depending on national regulations, which differ for every country, wireless microphones may operate in the various parts of the range between 470 MHz and 865 MHz. (for example, 470 - 806 MHz in the US). These frequencies are shared with over-the-air TV broadcasts, so when selecting a frequency, the user must know what frequencies to stay away from to avoid interference.| Channel | Frequency |
|---|---|
| U1 | 801.375 MHz |
| U2 | 801.875 MHz |
| U3 | 803.125 MHz |
| U4 | 803.750 MHz |
| U5 | 804.500 MHz |
| U6 | 805.750 MHz |
In the UK, use of wireless microphone systems requires a licence, except for the licence free bands of 173.8 MHz - 175.0 MHz and 863 MHz - 865 MHz (N.B. This is emphatically NOT TV Channel 69. Channel 69 is from 854 - 862 MHz. In the UK Channel 69 frequencies do require a licence from JFMG Ltd.: [1] ).
The UK communications regulator, Ofcom, has said it will auction part of the spectrum currently reserved for wireless microphones, to which objections have been raised by Andrew Lloyd Webber. [2] [3]
In many other countries wireless microphone use requires a licence. Some governments regard all radio frequencies as military assets and the use of unlicenced radio transmitters, even wireless microphones, may be severely punished.
Digital and Hybrid
Wireless microphone signals can not be transmitted digitally in an analog format over normal frequency modulated carriers (digital hybrid)is a system containing a compander that does a better job than traditional FM wireless but is still 100 percent analog FM modulation with no digital content. Digital wireless like the Zaxcom system is a narrow band digital wireless that offers 100% digital modulation of the carrier. One advantage of 100% digital encoding of the signal at the transmitter is that companding artifacts are bypassed, allowing for more linearity and dynamic range. The Zaxcom system allows Stereo signals can be sent over one RF carrier. Linear response down to 20 Hz is possible, unlike analog wireless microphones that often have reduced response below 100 Hz (though there are a few analog wireless products linear down to 50 Hz.) Also, control and status signals can be sent along with the digital audio data stream, yielding more accurate reporting on battery life and changes in user settings. With fully digital solutions, FM modulation artifacts dosn't affect the digital audio stream. A disadvantage to both hybrid and full digital wireless is that the radio spectrum used by a single transmitter is wider than for analog wireless, making it more difficult to coordinate a large-scale system with many wireless devices. Practical range for digital hybrid wireless is typically less than for full digital and normal analog wireless.Spread Spectrum technology can be used to put more wireless microphones in the same RF space.
Manufacturers working with digital wireless microphone technology include Lectrosonics, Sabine, and Zaxcom.
External links
- Introduction to Wireless Microphones at Sweetwater.com
- Discussion regarding the reassignment of Channel 69 frequencies
microphone, sometimes referred to as a mike or mic (both IPA pronunciation: [maɪk]), is an acoustic to electric transducer or sensor that converts sound into an electrical signal.
..... Click the link for more information.
..... Click the link for more information.
Shure Incorporated is a consumer and professional audio electronics corporation. Shure Incorporated mainly produces microphones and other audio electronics, but also produces in-ear monitors (earphones) for a variety of audio applications including MP3 players.
..... Click the link for more information.
..... Click the link for more information.
Sennheiser electronic GmbH & Co. KG
Private
Founded 1945 (as Labor W)
Headquarters Wennebostel, Germany
Key people Fritz Sennheiser, founder
Jörg Sennheiser, CEO
Industry Audio electronics
..... Click the link for more information.
Private
Founded 1945 (as Labor W)
Headquarters Wennebostel, Germany
Key people Fritz Sennheiser, founder
Jörg Sennheiser, CEO
Industry Audio electronics
..... Click the link for more information.
Norddeutscher Rundfunk (NDR) [North German Broadcasting] is a public radio and television broadcaster, based in Hamburg. In addition to the city-state of Hamburg, NDR transmits for the German Länder
..... Click the link for more information.
..... Click the link for more information.
Hung Chang Lin (Jimmy Lin) (born August 8, 1919) is a Chinese-American Inventor who currently resides in Maryland.
Hung C. Lin holds 61 U.S. patents. Among his inventions are the quasi-complementary amplifier which is used in mast commercial audio amplifiers.
..... Click the link for more information.
Hung C. Lin holds 61 U.S. patents. Among his inventions are the quasi-complementary amplifier which is used in mast commercial audio amplifiers.
..... Click the link for more information.
Rex Harrison
Rex Harrison pictured in 1947
Birth name Reginald Carey Harrison
Born 5 March 1908
Huyton, Knowsley, Lancashire, England
Died 2 May 1990 (aged 82)
..... Click the link for more information.
Rex Harrison pictured in 1947
Birth name Reginald Carey Harrison
Born 5 March 1908
Huyton, Knowsley, Lancashire, England
Died 2 May 1990 (aged 82)
..... Click the link for more information.
IMDb profile
My Fair Lady is an Academy Award-winning 1964 film adaptation of the stage musical, My Fair Lady, based in turn on the play Pygmalion by George Bernard Shaw.
..... Click the link for more information.
My Fair Lady is an Academy Award-winning 1964 film adaptation of the stage musical, My Fair Lady, based in turn on the play Pygmalion by George Bernard Shaw.
..... Click the link for more information.
microphone, sometimes referred to as a mike or mic (both IPA pronunciation: [maɪk]), is an acoustic to electric transducer or sensor that converts sound into an electrical signal.
..... Click the link for more information.
..... Click the link for more information.
Cycles per second: 300 MHz to 3 GHz
Wavelength: 1 m to 100 mm Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3 GHz, which is 300 MHz to 3,000 MHz.
..... Click the link for more information.
Wavelength: 1 m to 100 mm Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3 GHz, which is 300 MHz to 3,000 MHz.
..... Click the link for more information.
Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. It is also known as the meter band or meter wave as the wavelengths range from ten to one meters.
..... Click the link for more information.
..... Click the link for more information.
frequency modulation (FM) conveys information over a carrier wave by varying its frequency (contrast this with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant).
..... Click the link for more information.
..... Click the link for more information.
Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent.
..... Click the link for more information.
..... Click the link for more information.
microphone, sometimes referred to as a mike or mic (both IPA pronunciation: [maɪk]), is an acoustic to electric transducer or sensor that converts sound into an electrical signal.
..... Click the link for more information.
..... Click the link for more information.
diversity scheme refers to a method for improving the reliability of a message signal by utilizing two or more communication channels with different characteristics. Diversity plays an important role in combating fading and co-channel interference and avoiding error bursts.
..... Click the link for more information.
..... Click the link for more information.
Antenna diversity is a transmission technique in which the information-carrying signal is transmitted along different propagation paths. This can be achieved by using multiple receiver antennas (diversity reception) and/or by using multiple transmitting antennas (transmit
..... Click the link for more information.
..... Click the link for more information.
companding (occasionally called compansion) is a method of mitigating the detrimental effects of a channel with limited dynamic range. The name is a portmanteau of compressing and expanding.
..... Click the link for more information.
..... Click the link for more information.
In electronics, gain is a measure of the ability of a circuit to increase the power or amplitude of a signal. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system.
..... Click the link for more information.
..... Click the link for more information.
Clipping is a form of waveform distortion that occurs when an amplifier is overdriven, which happens through attempts to increase the voltage or current beyond its threshold of power.
..... Click the link for more information.
..... Click the link for more information.
In telecommunications, squelch is a circuit function that acts to suppress the audio (or video) output of a receiver in the absence of a sufficiently strong desired input signal.
..... Click the link for more information.
..... Click the link for more information.
Shure Incorporated is a consumer and professional audio electronics corporation. Shure Incorporated mainly produces microphones and other audio electronics, but also produces in-ear monitors (earphones) for a variety of audio applications including MP3 players.
..... Click the link for more information.
..... Click the link for more information.
Sennheiser electronic GmbH & Co. KG
Private
Founded 1945 (as Labor W)
Headquarters Wennebostel, Germany
Key people Fritz Sennheiser, founder
Jörg Sennheiser, CEO
Industry Audio electronics
..... Click the link for more information.
Private
Founded 1945 (as Labor W)
Headquarters Wennebostel, Germany
Key people Fritz Sennheiser, founder
Jörg Sennheiser, CEO
Industry Audio electronics
..... Click the link for more information.
Samson Technologies is an audio production conglomerate that is made up of the following companies or elements:
..... Click the link for more information.
- Samson Wireless
- Samson Audio
- Hartke Systems
- Zoom
- Armoured Cable
External links
- Official Samson Website
..... Click the link for more information.
AKG Acoustics (originally Akustische und Kino-Geraete Gesellschaft m.b.H.) is an Austrian manufacturer of audio electronics and accessories for professional and consumer markets.
..... Click the link for more information.
..... Click the link for more information.
Audio-Technica Corporation (株式会社オーディオテクニカ
..... Click the link for more information.
..... Click the link for more information.
transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications.
..... Click the link for more information.
..... Click the link for more information.
Phantom power (labeled as +48 V on some audio equipment) is a method that sends a DC electrical voltage through microphone cables. It is best known as a common power source for condenser microphones, though many active DI boxes also use it.
..... Click the link for more information.
..... Click the link for more information.
In electronic engineering, a DC to DC converter is a circuit which converts a source of direct current (DC) from one voltage level to another. It is a class of power converter.
..... Click the link for more information.
..... Click the link for more information.
Sony Corporation
ソニー株式会?
Public (TYO: 6758 ; NYSE: SNE )
Founded May 7 1946 (adopted current name in 1958) by Masaru Ibuka and Akio Morita[1]
Headquarters Minato-ku, Tokyo, Japan[1]
..... Click the link for more information.
ソニー株式会?
Public (TYO: 6758 ; NYSE: SNE )
Founded May 7 1946 (adopted current name in 1958) by Masaru Ibuka and Akio Morita[1]
Headquarters Minato-ku, Tokyo, Japan[1]
..... Click the link for more information.
Cycles per second: 300 MHz to 3 GHz
Wavelength: 1 m to 100 mm Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3 GHz, which is 300 MHz to 3,000 MHz.
..... Click the link for more information.
Wavelength: 1 m to 100 mm Ultra high frequency (UHF) designates a range (band) of electromagnetic waves whose frequency is between 300 MHz and 3 GHz, which is 300 MHz to 3,000 MHz.
..... Click the link for more information.
Ofcom is the independent regulator and competition authority for the communication industries in the United Kingdom[1]. Ofcom was initially established in the enabling device, the Office of Communications Act 2002
..... Click the link for more information.
..... Click the link for more information.
This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus
