Held Microphone

Held Microphone

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Replacement 600 Ohm Impedance Microphone Mic Cartridge L 818
Replacement 600 Ohm Impedance Microphone Mic Cartridge L 818
Paypal   US $10.08
X2 VTGAKAI DYNAMIC MIRCROPHONES MODEL ADM 6 NON DIRECTIONAL IMP 50K WITH STANDS
X2 VTGAKAI DYNAMIC MIRCROPHONES MODEL ADM 6 NON DIRECTIONAL IMP 50K WITH STANDS
Paypal   US $60.00
BG 58 40Hz 18KHz 600 Ohms Microphone Cartridge 30mm x 44mm
BG 58 40Hz 18KHz 600 Ohms Microphone Cartridge 30mm x 44mm
Paypal   US $10.11
Rode Boomplole for NTG 2 and other shotgun microphones 33 to 10 feet
Rode Boomplole for NTG 2 and other shotgun microphones 33 to 10 feet
Paypal   US $65.00
600 Ohms Replacement Dynamic Microphone Mic Cartridge DM 28
600 Ohms Replacement Dynamic Microphone Mic Cartridge DM 28
Paypal   US $12.37
2 50 CBI Studio Quad Mic Cables XLR BUY IT NOW FREE SHIPPING USA
2 50 CBI Studio Quad Mic Cables XLR BUY IT NOW FREE SHIPPING USA
Paypal   US $79.88
2 25 CBI Studio Quad Microphone Cables XLR Best Deal on eBay Free Shipping
2 25 CBI Studio Quad Microphone Cables XLR Best Deal on eBay Free Shipping
Paypal   US $62.88
4 50 CBI Studio Quad Mic Cables XLR FREE SHIPPING USA BUY IT NOW
4 50 CBI Studio Quad Mic Cables XLR FREE SHIPPING USA BUY IT NOW
Paypal   US $149.88
4 25 CBI Studio Quad Mic Cables XLR BUY IT NOW
4 25 CBI Studio Quad Mic Cables XLR BUY IT NOW
Paypal   US $122.88
Broadcast 35mm Conference Video Stand Microphone
Broadcast 35mm Conference Video Stand Microphone
Paypal   US $22.29
Male 3 Pin 3P XLR Connector Plug for Microphone MIC Cable
Male 3 Pin 3P XLR Connector Plug for Microphone MIC Cable
Paypal   US $3.74
AKG C414 TL II TL 2 condenser microphone mid 90s great shape
AKG C414 TL II TL 2 condenser microphone mid 90s great shape
Paypal   US $470.00
Mini Desk 35mm Studio Video Chat Microphone w Stand
Mini Desk 35mm Studio Video Chat Microphone w Stand
Paypal   US $24.29
Male 3 Pin XLR Jack Microphone MIC Audio Cable Connector
Male 3 Pin XLR Jack Microphone MIC Audio Cable Connector
Paypal   US $3.75
Male 3 Pin XLR Plug Audio Microphone Connector Adpater
Male 3 Pin XLR Plug Audio Microphone Connector Adpater
Paypal   US $3.57
Revolabs Solo Executive 8 Channel Wireless Microphone System 01 EXERAC BLK 11
Revolabs Solo Executive 8 Channel Wireless Microphone System 01 EXERAC BLK 11
Paypal   US $275.00
New Desk Top Tripod Mic Stand and Expandable Mic Clip
New Desk Top Tripod Mic Stand and Expandable Mic Clip
Paypal   US $9.95
New Expandable Mic Holder for Most Cordless and Corded
New Expandable Mic Holder for Most Cordless and Corded
Paypal   US $6.49
60Hz 16000Hz Dynamic Microphone Cartridge L 818 Yellow Black
60Hz 16000Hz Dynamic Microphone Cartridge L 818 Yellow Black
Paypal   US $12.71
VINTAGE PHILLIPS MICROPHONE MODEL TYPE EL 6100 00
VINTAGE PHILLIPS MICROPHONE MODEL TYPE EL 6100 00
Paypal   US $6.30
Hisonic HSU8900H 4x100Ch UHF Wireless Hand Held Mic Microphone System
Hisonic HSU8900H 4x100Ch UHF Wireless Hand Held Mic Microphone System
Paypal   US $399.99
Audio Technica ATR 30 Dynamic Cable Professional Microphone Cord Used
Audio Technica ATR 30 Dynamic Cable Professional Microphone Cord Used
   US $29.99
Vintage Turner Division Conrac Corp 250 251 Lo Z Microphone Desk Base USA Made
Vintage Turner Division Conrac Corp 250 251 Lo Z Microphone Desk Base USA Made
Paypal   US $29.99
Realistic Universal Replacement Cassette Wired Recorder Microphone Radio Shack
Realistic Universal Replacement Cassette Wired Recorder Microphone Radio Shack
Paypal   US $12.99
Heil Sound PR 35 PR 35 PR35 Dynamic Cable Microphone Hiel
Heil Sound PR 35 PR 35 PR35 Dynamic Cable Microphone Hiel
Paypal   US $225.00
Sennheiser ew 135 ew 100 G2 Wireless Hand Held Microphone ew100 ew135 E835
Sennheiser ew 135 ew 100 G2 Wireless Hand Held Microphone ew100 ew135 E835
Paypal   US $232.50
PYLE PRO Dual Channel UHF Wireless Microphone System WIRELESS MIC
PYLE PRO Dual Channel UHF Wireless Microphone System WIRELESS MIC
Paypal   US $155.98
Sony ECM MS907 Condenser Cable Consumer Microphone
Sony ECM MS907 Condenser Cable Consumer Microphone
Paypal   US $29.99
Sennheiser MD 421 Dynamic Cable Professional Microphone
Sennheiser MD 421 Dynamic Cable Professional Microphone
Paypal   US $200.00
Sennheiser MD421 Dynamic Cable Professional Microphone
Sennheiser MD421 Dynamic Cable Professional Microphone
Paypal   US $275.00
2 Rackmounted Vega R 662A R 662 Wireless Receivers R662A R662 MIC Microphone
2 Rackmounted Vega R 662A R 662 Wireless Receivers R662A R662 MIC Microphone
Paypal   US $125.00
Audio Technica AT853a Podium Condenser Microphone
Audio Technica AT853a Podium Condenser Microphone
Paypal   US $39.95
Dynamic Microphone Cartridge 40Hz 18KHz Frequency Response
Dynamic Microphone Cartridge 40Hz 18KHz Frequency Response
Paypal   US $9.51
VocoPro UHF 8800 8 Channel Wireless Microphone System
VocoPro UHF 8800 8 Channel Wireless Microphone System
Paypal   US $449.00
DM 28 80Hz 16KHz 30 x 45mm Dynamic Mic Microphone Cartridge
DM 28 80Hz 16KHz 30 x 45mm Dynamic Mic Microphone Cartridge
Paypal   US $9.59
MXL 990991 Condenser Cable Professional Microphone
MXL 990991 Condenser Cable Professional Microphone
Paypal   US $15.50
Lot 2 SHURE WH20QTR Head Worn Dynamic Microphone Headset with 1 4 Phone Jack
Lot 2 SHURE WH20QTR Head Worn Dynamic Microphone Headset with 1 4 Phone Jack
Paypal   US $99.00
Audix Fusion 4 Cable Professional Microphone
Audix Fusion 4 Cable Professional Microphone
Paypal   US $40.00
Audio Technica ATW 3141 Hand Held Microphone System D Band 655 681 MHz
Audio Technica ATW 3141 Hand Held Microphone System D Band 655 681 MHz
Paypal   US $375.00
AKG C 3000 B Condenser Cable Professional Microphone
AKG C 3000 B Condenser Cable Professional Microphone
Paypal   US $57.78
Replacement PS 998 500 Ohms Impedance Microphone Cartridge
Replacement PS 998 500 Ohms Impedance Microphone Cartridge
Paypal   US $9.80
Shure Wireless Microphone L4 V hand held sm58
Shure Wireless Microphone L4 V hand held sm58
Paypal   US $122.50
SANSUI SDM 2 Dynamic Microphone New in Box
SANSUI SDM 2 Dynamic Microphone New in Box
Paypal   US $4.99
Conferencing Video Stand Microphone 35mm Broadcast
Conferencing Video Stand Microphone 35mm Broadcast
Paypal   US $23.56
Vintage AKAI Dynamic Microphone Non Directional MIB
Vintage AKAI Dynamic Microphone Non Directional MIB
Paypal   US $15.50
Shure Beta 87 Super Cardioid Handheld Vocal Microphone Mic BETA87A
Shure Beta 87 Super Cardioid Handheld Vocal Microphone Mic BETA87A
Paypal   US $284.95
Sky Wireless Wired Microphone corded mic OR wireless w Transmitter ReceiverCase
Sky Wireless Wired Microphone corded mic OR wireless w Transmitter ReceiverCase
Paypal   US $44.95
Golden Large Diaphragm Studio Microphone Recording Mic
Golden Large Diaphragm Studio Microphone Recording Mic
Paypal   US $49.99
Pro 200 Channel Wireless UHF Microphone System
Pro 200 Channel Wireless UHF Microphone System
Paypal   US $115.00
Pro 4 Channel VHF wireless Microphone Mic System New
Pro 4 Channel VHF wireless Microphone Mic System New
Paypal   US $129.00

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For More choices check out Held Microphone some of our other merchants.

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Telefunken M 80 Hand-Held Vocal Microphone


Telefunken M 80 Hand-Held Vocal Microphone


$249


The Telefunken M 80 microphone is a durable and versatile dynamic mic. Its directional pickup pattern and wide frequency response yield a blend of functionality, isolation, andmost importantlytone. It is sonically open, requiring little or no EQing to get it to fit into the mix. Minimal proximity effect gives it a smooth, balanced tone that is not too boomy or big.The M 80 mic combines a low-mass voice coil with a super-thin Mylar membrane and a high-quality step-up output transformer from AMI/TAB-Funkenwerk. Its extremely rugged design allows it to withstand serious abuse, and its black rubberized finish, recessed Telefunken badge, and chromed-head grille give it a classic Telefunken look.In use, the Telefunken M 80 microphone exhibits superior feedback rejection in a live environment. On vocals, it's clear and controlled, capturing the nuances of a performance with great detail while keeping sibilance and handling noise to a minimum. On drums, the Telefunken M 80 is tight, punchy, and open, with emphasis on the initial attack. Guitars bloom with richness and clarity, and percussion cuts with ease.Directional pickup pattern and wide frequency responseLow-mass voice coil with super-thin Mylar membraneRugged design, black rubberized finish, and chromed-head grilleSuperior feedback rejection during live performanceideal for vocals, drums, guitars, and more

Sennheiser E822s Dynamic Hand-Held Vocal Microphone


Sennheiser E822s Dynamic Hand-Held Vocal Microphone


$69.99


The Sennheiser e822S Dynamic Handheld Vocal Microphone's cardioid pickup pattern rejects rear-axis sounds. It features metal construction, internal shockmounting, hum-compensating coil, neodymium ferrous magnet with boron, and on/off switch with on-lock. 80Hz-12kHz. Precision manufactured in Germany. The Dynamic includes a 10-year warranty!Note: This mic does not include a clip. You may wish to order a mic clip (sold separately).Dynamic micPrecision manufactured in GermanyCardioid patternMetal constructionInternal shockmountingHum-compensating coilNeodymium ferrous magnet with boronOn/off switch that can be locked in on position80Hz-12kHz frequency responseIncludes 10-year warranty

Audio-Technica At2010 Hand-Held Condenser Microphone


Audio-Technica At2010 Hand-Held Condenser Microphone


$99


The Audio-Technica AT2010 microphone is designed to bring the studio-quality articulation and intelligibility of Audio-Technica's renowned 20 Series to the stage. Featuring the same 16 mm low-mass diaphragm found in the critically acclaimed AT2020 side-address studio condenser, the AT2010 mic excels wherever articulate vocals are needed: in houses of worship, for solo performances, jazz vocalists, singer/songwriters, and more. This breakthrough handheld vocal condenser delivers remarkable specs and superior build at an amazing price. State-of-the-art design and manufacturing techniques ensure compliance with Audio-Technica's stringent consistency and reliability standards, and set the AT2010 apart from other vocal mics in its class. The microphone offers a wide dynamic range and handles high SPLs with ease. Its rugged construction is designed to stand up to years of use. Requires phantom power.Extended frequency response and superior transient response for smooth, natural sonic characteristics High SPL handling and wide dynamic range provide unmatched versatility Cardioid polar pattern reduces pickup of sounds from the sides and rear, improving isolation of desired sound source Multi-stage grille design offers excellent protection against plosives and sibilance without compromising high-frequency clarity Corrosion-resistant contacts from gold-plated XLRM-type connector Rugged, all-metal and construction for years of trouble-free service Quiet-Flex stand clamp provides silent, flexible microphone positioning Fixed-charge back plate permanently polarized condenser

Digital Reference DR-1600 Dynamic Hand-Held Wireless Microphone System  889406918214


Digital Reference DR-1600 Dynamic Hand-Held Wireless Microphone System 889406918214


$84.99


The Digital Reference DR-1600 Dynamic Hand-Held Wireless Microphone System delivers super frequency flexibility via 3 VHF frequency bands (169.505MHz, 170.245MHz, and 171.905MHz). The handheld mic/transmitter gives you up to 20 hours of battery life. The DR-1600 features an advanced dipole antenna system and adjustable squelch control with a removable docking power supply that inserts into receiver back.

Digital Reference Drv100 Dynamic Cardioid Hand-Held Microphone


Digital Reference Drv100 Dynamic Cardioid Hand-Held Microphone


$49.99


The Digital Reference DRV100 Dynamic Vocal Microphone is an all-around mic for stage vocals. Built with a rugged grille, all-metal body, and optimized frequency response, the DRV100 microphone stands up to long hours of use while providing uncompromising vocal reproduction. Ideal for any musical style or speech application, the great-sounding and durable DRV100 microphone is the must-have for every gig bag.Outstanding vocal reproduction for any musical styleCardioid polar pattern for wider pickup areaDynamic capsule, rugged grille, all-metal body, and gold-plated XLR connectorIncludes microphone clip

Shure Slx24/Beta87a Hand-Held Wireless Condenser Microphone System


Shure Slx24/Beta87a Hand-Held Wireless Condenser Microphone System


$729


Sound installations and working bands need powerful wireless tools that can be set up quickly and used confidently. Shure's rugged SLX24/Beta87A Hand-Held Wireless System exceeds these demands with innovative automatic setup features, such as auto frequency scan and transmitter setup, exceptional wireless clarity, and legendary Shure sound.The Shure SLX24/Beta87A Hand-Held Wireless System for vocalists includes an SLX2 hand-held microphone transmitter fitted with a Beta87A capsule and the SLX4 diversity receiver.Beta 87A Vocal MicrophoneLeading the field for studio-quality sound in live performance, the Shure Beta 87A condenser element has a tailored response for warm, accurate sound. Its supercardioid design provides maximum isolation from nearby vocalists or instruments. SLX2 Wireless Handheld TransmitterSLX Wireless Handheld Transmitter with timed backlit LC display, frequency and power lockout, and "Mute" functionalitySLX4 Wireless ReceiverSLX Wireless Diversity Receiver with PS20 (120V AC) Power Supply, 1/4 Wave Antennas, and Rack Mounting HardwareAutomatic Frequency SelectionAutomatic Transmitter Setup960 Selectable frequencies across 24MHz bandwidthDetachable 1/4 wave antennasMicroprocessor-controlled diversityRF presence LED5-segment audio meterMulti-function, backlit LCDLow battery indicatorFrequency and power lockoutRugged metal chassisVolume control on rear of unit1/2 rack designFurnished rack hardwareNon-slip bumpers for use out of rackXLR and 1/4" outputs

Electro-Voice Re510 Hand-Held Condenser Supercardioid Vocal Microphone


Electro-Voice Re510 Hand-Held Condenser Supercardioid Vocal Microphone


$249


The Electro-Coice RE510 microphone has a 5/8"-diameter self-biased condenser capsule that delivers big-capsule studio performance without sacrificing off-axis performance or transient response. Supercardioid polar pattern for superior feedback rejection and acoustic isolation. Low-frequency roll-off switch enables tailoring of low-frequency response to meet application requirements. The precision electronic design of the RE510 Microphone provides extremely low distortion and outstanding transient response. High current differential output stage can drive long microphone cables without loss of performance. The mic's Warm Grip handle provides a comfortable feel while the multistage pop filter eliminates plosives. 3-year warranty.Requires phantom power.5/8"-diameter self-biased condenser capsuleSupercardioid polar patternLow-frequency roll-off switchExtremely low distortionOutstanding transient responseHigh current differential output stageWarm Grip handleMultistage pop filter40Hz-20kHz frequency response3-year warranty

Akg Elle C Hand-Held Vocal Condenser Microphone White


Akg Elle C Hand-Held Vocal Condenser Microphone White


$229


Building on decades of experience in making microphones, AKG has designed a professional vocal microphone with a condenser transducer perfectly tailored to the female voice. The result is called the "Elle C" and delivers an extremely accurate, detailed, and natural sound. In addition to its superb audio performance, the AKG Elle C also matches the highest aesthetic expectations of performing female vocalists. Its slender, elegant silhouette adds an exciting visual dimension to every performance. Requires phantom power.Condenser vocal microphone for female singers Slender and elegant silhouette XLR connector module with 24-carat gold plated pins for optimized connectivity 24-carat gold plated transducer case for optimum conductivity and resistance to corrosion and humidity Spring steel wire-mesh grill for extreme ruggedness incl. reliable control of pops and wind noise Internal elastic suspension

Used Akg Elle C Hand-Held Vocal Condenser Microphone White


Used Akg Elle C Hand-Held Vocal Condenser Microphone White


$208.39


Building on decades of experience in making microphones, AKG has designed a professional vocal microphone with a condenser transducer perfectly tailored to the female voice. The result is called the "Elle C" and delivers an extremely accurate, detailed, and natural sound. In addition to its superb audio performance, the AKG Elle C also matches the highest aesthetic expectations of performing female vocalists. Its slender, elegant silhouette adds an exciting visual dimension to every performance. Requires phantom power.Condenser vocal microphone for female singers Slender and elegant silhouette XLR connector module with 24-carat gold plated pins for optimized connectivity 24-carat gold plated transducer case for optimum conductivity and resistance to corrosion and humidity Spring steel wire-mesh grill for extreme ruggedness incl. reliable control of pops and wind noise Internal elastic suspension

Electro-Voice Re410 Hand-Held Condenser Cardioid Vocal Microphone


Electro-Voice Re410 Hand-Held Condenser Cardioid Vocal Microphone


$199


The versatile Electro-Voice RE410 is a handheld condenser vocal microphone that provides a crisp, clear top; sweet midrange; and pulls the voice out of the mix in a crowded spectrum. 40Hz-20kHz frequency response. Its cardioid pattern helps reject feedback loops and delivers acoustic isolation while the Warm-Grip handle provides a comfortable feel. High-compliance shockmount effectively eliminates handling noise and the multistage pop filter eliminates plosives. 3-year warranty.Requires phantom power.Handheld condenser vocal microphoneCardioid patternWarm-Grip handleHigh-compliance shockmountMultistage pop filter

Used Electro-Voice Re410 Hand-Held Condenser Cardioid Vocal Microphone


Used Electro-Voice Re410 Hand-Held Condenser Cardioid Vocal Microphone


$181.09


The versatile Electro-Voice RE410 is a handheld condenser vocal microphone that provides a crisp, clear top; sweet midrange; and pulls the voice out of the mix in a crowded spectrum. 40Hz-20kHz frequency response. Its cardioid pattern helps reject feedback loops and delivers acoustic isolation while the Warm-Grip handle provides a comfortable feel. High-compliance shockmount effectively eliminates handling noise and the multistage pop filter eliminates plosives. 3-year warranty.Requires phantom power.Handheld condenser vocal microphoneCardioid patternWarm-Grip handleHigh-compliance shockmountMultistage pop filter

Used Sennheiser E822s Dynamic Hand-Held Vocal Microphone


Used Sennheiser E822s Dynamic Hand-Held Vocal Microphone


$63.69


The Sennheiser e822S Dynamic Handheld Vocal Microphone's cardioid pickup pattern rejects rear-axis sounds. It features metal construction, internal shockmounting, hum-compensating coil, neodymium ferrous magnet with boron, and on/off switch with on-lock. 80Hz-12kHz. Precision manufactured in Germany. The Dynamic includes a 10-year warranty!Note: This mic does not include a clip. You may wish to order a mic clip (sold separately).Dynamic micPrecision manufactured in GermanyCardioid patternMetal constructionInternal shockmountingHum-compensating coilNeodymium ferrous magnet with boronOn/off switch that can be locked in on position80Hz-12kHz frequency responseIncludes 10-year warranty

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If you didn"t find what you wanted look below for Held Microphone in the Amazon Marketplace.

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GTD Audio Hand held Microphone Mic For GTD Audio G-787, G-733 Receiver GTD Audio Hand held Microphone Mic For GTD Audio G-787, G-733 Receiver
List Price: $59.00
Sale Price: $36.00

This Hand Held Microphone will be compatible with GTD Audio G-787, G-733 receiver only

Nady DKW DUO HT/B/D VHF Dual Receiver Handheld Microphone System Nady DKW DUO HT/B/D VHF Dual Receiver Handheld Microphone System
List Price: $79.99
Sale Price: Too low to display

The Nady DKW DUO HT/B/D is a VHF dual receiver for single or simultaneous dual microphone operation. It is an ideal entry-level system with all the advantages and freedom of wireless operation without cumbersome cords...

Midland GXT1000VP4 36-Mile 50-Channel FRS/GMRS Two-Way Radio (Pair) (Black/Silver) Midland GXT1000VP4 36-Mile 50-Channel FRS/GMRS Two-Way Radio (Pair) (Black/Silver)
List Price: $89.99
Sale Price: $55.01
Used From: $55.56

Midway's GXT1000VP4 two-way, 22-channel radios are designed for GMRS (General Mobile Radio Service) operation, in a rugged, weatherproof package. With a range of up to 36 miles, they're perfect for most any adventure...

Azden WMS-PRO Wireless Microphone System Azden WMS-PRO Wireless Microphone System
List Price: $279.99
Sale Price: $159.00
Used From: $137.99

Azden's WMS-PRO wireless microphone system offers untethered convenience and clear FM transmission from compact, unobtrusive components. The system consists of Azden's WM-PRO transmitter, WR-PRO receiver, EX-503 clip-on electret microphone, and EX-413 handheld microphone...

GTD Audio Battery Cover For Hand held Microphone GTD Audio Battery Cover For Hand held Microphone
Sale Price: $6.95

Battery Cover Fits G-622, G-788, G-900, G-787 hand held microphone

Pyle-Pro PDWM4300 4 Mic VHF Wireless Rack Mount Microphone System Pyle-Pro PDWM4300 4 Mic VHF Wireless Rack Mount Microphone System
List Price: $337.99
Sale Price: Too low to display
Used From: $115.10

Using manufacturing breakthroughs pioneered by Pyle, the PDWM4300 system redefines the price point for quality microphones. Class A solid state electronics are engineered for low noise, distortion and coloration...

Pyle-Pro PDMIC58 Professional Moving Coil Dynamic Handheld Microphone Pyle-Pro PDMIC58 Professional Moving Coil Dynamic Handheld Microphone
List Price: $39.99
Sale Price: Too low to display

The PDMIC58 is a professional moving coil dynamic handheld microphone. Translation: it makes your voice sound great, thanks the unidirectional element. The durable zinc alloy metal construction means this mic is great for everyday use...

GTD Audio Hand held Microphone Mic For G-622 GTD Audio Hand held Microphone Mic For G-622
List Price: $59.00
Sale Price: $35.00

This Hand Held Microphone will be compatible with GTD Audio G-622 receiver only

Shure PG24/PG58 Wireless Vocal System, H7 Shure PG24/PG58 Wireless Vocal System, H7
List Price: $374.00
Sale Price: $245.00
Used From: $220.01

Includes PG4 Diversity Receiver with PG2/PG58 Handheld Microphone Transmitter, tuned to accentuate the clarity of lead and backup vocals.

Pyle-Pro PDWM8400 8 Mic Professional Handheld VHF Wireless Microphone System Pyle-Pro PDWM8400 8 Mic Professional Handheld VHF Wireless Microphone System
List Price: $593.99
Sale Price: Too low to display
Used From: $179.28

This 8-channel wireless microphone system is perfect at an event or party when you need powerful wireless coverage. This professional system features dual telescoping receiver antennas for the highest quality signal...


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Held Microphone

The Development of The First Microphones

The invention of the microphone was a result of the development of the telephone. As a technology was developed to transmit sound over a distance as an electrical signal, methods of converting sound into electrical impulses were required. The very first microphones were bulky, awkward and performed poorly. They used liquid mercury as a variable resistor, and tended to muffle out sound. A more sensitive and mobile solution was needed.

In 1881 Henry Runnings devised a transmitter wherein the variable resistance medium consisted of a mass of finely divided carbon granules held between two conducting plates. Between a metal diaphragm, and a parallel conducting plate, and a mouthpiece, is a chamber filled with fine granules of carbon. The diaphragm, and the plate, form the terminals of the transmitter, and the current from the battery must therefore flow through the mass of granular carbon.

When the diaphragm is caused to vibrate by sound waves, it is brought into more or less intimate contact with the carbon granules and causes a varying pressure between them. The resistance offered by them to the current is thus varied, and the desired undulations in the current produced. This transmitter, instead of having one or a few points of variable contact, is seen to have a multitude of them.

It can carry a larger current without heating, and at the same time produce greater changes in its resistance, than the forms previously devised, and no ordinary sound can cause a total break between the electrodes. These and other advantages have caused this type in one form or another to largely displace all others.

At first the practice was to put the transmitter, together with the receiver and battery, directly in circuit with the line wire, With this arrangement the changes produced in the resistance by the transmitter were small in comparison with the total resistance of the circuit, especially in the case of a long line, and the changes in current were therefore small. Edison remedied this difficulty by using an induction coil in connection with the transmitter.

The induction coil used then and now is made as follows : Around a core formed of a bundle of soft iron wires is wound a few turns of comparatively heavy insulated copper wire. Outside of this, and entirely separate from it, is wound another coil consisting of a great number of turns of fine wire, also of copper, and insulated. The transmitter, together with the battery, is placed in a closed circuit with the coarse winding of a few turns, while the fine winding of many turns is included directly in circuit with the line wire and the receiving instrument.

The coarse winding is usually termed the primary winding, because it is associated with the primary source of current, the battery; while the fine winding is usually termed the secondary winding, because the currents flowing in it at the transmitting station are secondary, or induced currents. In coils of this kind the coarse winding, is almost invariably termed the primary for the above reason, although many conditions exist in electrical work, and in telephone work, where the high resistance winding is in reality the primary coil.

About the Author

Malcolm Blake is fascinated by modern technology, and the paths of development through history that lead to where we are today. He writes articles on topics such as Telephone Reverse Search and Reverse Yellow Pages.