Sound is an amazing thing . All of the different noises wehearare because of minute press differences in the air around us . What ’s great about it is that the air communicate those pressure changes so well — and so accurately — over relatively long distances .
If you ’ve readHow CDs Work , you learned about the very first mike . It was a metallic element midriff attached to a needle , and this phonograph needle scratched a pattern onto a piece of metal foil . The pressure differences in the air that go on when someone spoke toward the diaphragm moved the diaphragm , which moved the needle , which then recorded on the foil . When the needle was later run back over the foil , the quiver scratched on the hydrofoil would then move the diaphragm and re - make the sound . The fact that this strictly mechanical organisation work shows how much vitality the quivering in the line can have .
All modernistic microphones are trying to accomplish the same affair as the original but do it electronically rather than automatically . A microphone wants to take varying pressure wafture in the tune and convert them into varying electrical signaling . There are several different technologies commonly used to carry through this transition . Take a flavor at the next page to learn more about different types of mics — including one of the first invented by Alexander Graham Bell .
10: Liquid Microphone
Liquid microphones , cook up by Alexander Graham Bell and Thomas Watson , wereamong the first working microphonesto be developed , and they were a precursor to what would later become the condenser mike . former liquid microphones used a alloy cup occupy with piss and sulphuric acid . A stop was place over the cupful with a phonograph needle on the receiving side of the diaphragm . healthy wave would make the phonograph needle to move in the weewee . A diminished electrical electric current ran to the needle , which was modulated by reasoned vibrations . The liquid mike was never a particularly functional gadget , but it makes a great science experiment
9: Carbon Microphone
The oldest and simplest microphone use carbon copy debris . This is the technology used in the firsttelephonesand is still used in some telephones today . The C dust has a thin metal or credit card diaphragm on one side . As sound wafture hit the diaphragm , they compress the carbon copy dust , which changes its ohmic resistance . By running a current through the carbon , the changing resistance modify the amount of current that flows . They are still used in minelaying and chemical substance manufacturing because higher line voltages might cause explosions .
8: Fiber Optic Microphone
fibre - opticsystems , which apply tops - thin chain of methamphetamine hydrochloride to transmit selective information rather of traditional metal wire , have been revolutionizing the champaign of telecommunications in recent long time , including microphone technology . So , what ’s the big wad ? Unlike conventional mics , which are often big and send an electric signal , fiber optic microphone can be extremely modest , and they can be used in electrically sensitive environments . They can also be produced with no metal , which realize them very useful in magnetised plangency imaging ( MRI ) applications and other billet where wireless frequency interference is an issue [ reference : Fibersound Audio ] .
7: Dynamic Microphone
Adynamic microphonetakes advantage of electromagnet personal effects . When a attractor move past a wire ( or coil of wire ) , the magnet cause current to run in the telegram . In a dynamic microphone , the diaphragm moves either a attractive feature or a coil when intelligent waves hit the contraceptive diaphragm , and the movement creates a small current . This type is best placed close to a vocalizer or instrumental role and does n’t typically pick up speech sound from more than a foot aside .
The modern dynamic mic is what most people plausibly picture when they think of a mike , with a slender cannular body and a orotund transcription head on top . They ’re an passing vulgar sight at live music show and karaoke because they wreak a balance of reliability , portability and sound quality .
6: Electret Microphone
Electret microphone are among the most wide used microphones on Earth . Because they ’re cheap and relatively dewy-eyed , electret mics are used incell phones , computersand hands - loose headset . An electret mike is a case of condenser microphone in which the external charge is replaced with an electret fabric , which by definition is in a lasting state of galvanising polarisation . They are also utilitarian in infotainment and news yield , astiny " lapel " micswhich can be discreetly aim on an interview study ’s clothing [ source : BeStar Acoustic Components ] .
5: Ribbon Microphone
In aribbon mike , a thin ribbon — usually aluminum , duraluminum or nanofilm — is suspended in a magnetized field . heavy waves move the ribbon , which changes the current flowing through it . medal microphones are bidirectional meaning they pick up sounds from both side of the mic .
The RCA PB-31 was one of the first ribbon microphone . It was create in 1931 and changed the audio frequency and broadcast medium industries because it set a unexampled measure when it came to clarity . Several other microphone makers made comparable modeling , include the BBC - Marconi Type A and ST&C Coles 4038 .
These mics fall out of fashion after the other radio day , and were usurped by dynamic and capacitance poser , because the chintzy ribbon inside made them exceedingly fragile . One of these can easily require mending after one inauspicious bump from a technician . Modern sound studio will still occasionally expend medal mics when they ’re looking to record a trail with an bona fide " vintage " sound .
4: Laser Microphone
A laser mike worksby capturing vibrations off a plane , like a windowpane , for example , and transmitting the signal back to a photo detector , which win over the reflected laser beam into an audio signal . When sound hits the windowpane , it twist and causes the laser beam to deflect , which can be translated to vocalise using a photocell . In late years , scientists have been formulate a new case of laser microphone that works by streaming smoke across a optical maser beam that ’s get at photocell , which is then convert to an audio signal . This eccentric is n’t befit for universal sound recording , like music , but is great for espionage , as the optical maser can in secret cut across sound over extreme distance .
3: Condensor Microphone
Acondenser microphoneis essentially acapacitor , with one dental plate of the capacitor move in response to sound waves . The movement changes the voltage of the condenser , and these variety are amplified to create a mensurable signal . Condenser microphones usually need a smallbatteryto provide avoltageacross the electrical condenser . Many modernistic consumer - grade condenser mics can also get their office from a USB connector to your PC .
Condenser mics are often used in recoding studios . There aretwo varietiesof condenser microphone : turgid stop , and belittled diaphragm . gravid diaphragm devices are democratic for vocals and instruments with a wad of bass or mid - range sound . While modest diaphragm mics are more compact , and pick up higher frequency sounds such as string instrument or cymbals .
2: Microelectromechanical Microphone
Themicroelectromechanical microphone(MEMS for short ) is an evolution of the electret design , and is begin to supercede it in some jail cell earphone and headset . The MEMS mic can be made even pocket-sized than electret , at just a few millimeters wide of the mark . Within that tiny space is a microprocessor chip moderate the mechanical sound diaphragm , a condenser to change sound gather as electrical current , an amplifier to boost that current ’s signaling , and a digital convertor to ferment it into audio data which can be used by smartphones and electronic computer .
1: Crystal Microphone
sure crystals alter their electric property as they change shape ( seeHow Quartz Watches Workfor one representative of this phenomenon ) . By sequester a contraceptive diaphragm to a crystal , thecrystal will produce a signalwhen sound waves hit the diaphragm . These mics were very cheap to produce , and so found use in budget - favorable program throughout the 20th hundred . Their heavy quality get out a lot to be want , however , causing them to be replaced by modernistic condenser and dynamic microphones . now , vitreous silica microphones are used principally formonitoring and for automotive transmitter and sensors .
As you may see , just about every technology conceivable has been harnessed to convert sound waves into electrical signals . The one matter most have in vernacular is the diaphragm , which gathers the sound waves and creates cause in whatever technology is being used to create the signal .
