Microphones-Type, Characteristics, design, Applications, techniques, Patterns

Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recordings etc. Its one of the most important part in the audio chain. The different types of microphones are used for different applications. Lets us see one by one…..

1. AUDIOGRAPHY
UNIT -2
PREPARED BY
SANKARANARAYANAN K. B
ASST. PROFESSOR
DEPARTMENT OF VISUAL COMMUNICATION
NEHRU ARTS AND SCIENCE COLLEGE(Autonomous)
COIMBATORE

2. Expected outcomes
Studentswillbeabletounderstandaboutthe
variousmicrophonesusedindifferentmedia.
Studentswillbeabletoremembertheworking
patternanddirectionalityofdifferentmicrophone
types.
Studentswillbeabletochoosethemicrophones
accordingtothepurposeofrecording.
Studentsknowaboutthebasictypes,and
characteristicsofeachmicrophone.

3. SYLLABUS –Unit 2
Microphones-Type,Characteristics,design,
Applications,techniques,Patterns.Loudspeaker-
Types,designs,Application,Crossover,Amplifiers-
Amplifications,Preamplifier,VCA,DCAConcept,
PowerAmplifiers,Impedanceamplifier,Types,Uses,
Characteristics.SignalProcessor-DynamicProcessor,
Time-dependentprocessor,multipleeffect
processors,Conceptofplug-in,Sidechaining
analoguev/sdigitalprocessors.Cablesand
Connectors-XLR,TRS,TRRS,TS,RCA,SPDIP,AES/EBU
andfiberopticCablesandConnectors.

4. Introduction
Microphonesareusedinmanyapplications
suchastelephones,hearingaids,public
addresssystemsforconcerthallsandpublic
events,motionpictureproduction,liveand
recordedaudioengineering,soundrecordings
etc.Itsoneofthemostimportantpartinthe
audiochain.Thedifferenttypesof
microphonesareusedfordifferent
applications.Letsusseeonebyone…..

5. Microphones
Amicrophone,colloquiallynamedmicisadevice–atransducer–that
convertssoundintoanelectricalsignal.Microphonesareusedinmany
applicationssuchastelephones,hearingaids,publicaddresssystemsfor
concerthallsandpublicevents,motionpictureproduction,liveand
recordedaudioengineering,soundrecording,two-way
radios,megaphones,radioandtelevisionbroadcasting,andincomputers
forrecordingvoice,speechrecognition,VoIP,andfornon-acousticpurposes
suchasultrasonicsensors.
Thefirstmicrophonethatenabledpropervoicetelephonywasthe(loose-
contact)carbonmicrophone.ThiswasindependentlydevelopedbyDavid
EdwardHughesinEnglandandEmileBerlinerandThomasEdisonintheUS.

6. Inside a Microphone
Thesensitivetransducerelementofamicrophoneis
calleditselementorcapsule.Soundisfirst
convertedtomechanicalmotionbyvibrationofa
diaphragm,themotionofwhichisthenconvertedto
anelectricalsignal.
Acompletemicrophonealsoincludesahousing,
somemeansofbringingthesignalfromtheelement
tootherequipment,andoftenanelectroniccircuitto
adapttheoutputofthecapsuletotheequipment
beingdriven.
Awirelessmicrophonecontainsaradiotransmitter.

7. Types of Microphones
Microphonesarecategorized
bytheirtransducerprinciple,
suchascondenser,dynamic,
etc.,andbytheirdirectional
characteristics.Sometimes
othercharacteristicssuchas
diaphragmsize,intendeduse
ororientationoftheprincipal
soundinputtotheprincipal
axis(end-orside-address)of
themicrophoneareusedto
describethemicrophone.
Dynamic Mic
Condenser Mic
Ribbon Mic
Carbon Microphones, Piezoelectric, Fiber-optic, Electretcondenser, Laser, Liquid Microphones

8. Dynamic Mic
Thedynamicmicrophone(alsoknownas
the moving-coilmicrophone)works
viaelectromagneticinduction.Theyarerobust,
relativelyinexpensiveandresistanttomoisture.
This,coupledwiththeirpotentiallyhighgainbefore
feedback,makesthemidealforon-stageuse.
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.terralec.co.uk%2FMicrophones.aspx&psig=AOvVaw2KwRU7Pkiweyh56sHr
vdH&ust=1592047456108000&source=images&cd=vfe&ved=0CA0QjhxqFwoTCIDctpKV_OkCFQAAAAAdAAAAABA3

9. Dynamic Mic
Dynamicmicrophonesusethesamedynamicprincipleasin
aloudspeaker,onlyreversed.Asmallmovableinductioncoil,
positionedinthemagneticfieldofapermanentmagnet,is
attachedtothediaphragm.Whensoundentersthroughthe
windscreenofthemicrophone,thesoundwavemovesthe
diaphragm.Whenthediaphragmvibrates,thecoilmovesin
themagneticfield,producingavaryingcurrentinthecoil
throughelectromagneticinduction.
https://www.google.com/url?sa=i&url=https%3A%2F%2Fgiphy.com%2Fstickers%2Fmicrophone
UuW1l47hGuTo4&psig=AOvVaw2KwRU7Pkiweyh56sHrvdH&ust=1592047456108000&source
=images&cd=vfe&ved=0CA0QjhxqFwoTCIDctpKV_OkCFQAAAAAdAAAAABAt

10. Parts in Dynamic Mic
1.Sound Waves
2.Diaphragm
3.Voice Coil
4.Magnet
5.Signal Wires (+ & -)

11. Condenser Mic
Thecondensermicrophone,inventedatWesternElectric
in1916byE.C.Wenteisalsocalledacapacitor
microphoneorelectrostaticmicrophone—capacitors
werehistoricallycalledcondensers.
Here,thediaphragmactsasoneplateofacapacitor,
andthevibrationsproducechangesinthedistance
betweentheplates.
Therearetwotypes,dependingonthemethodof
extractingtheaudiosignalfromthetransducer:DC-
biasedmicrophones,andradiofrequency(RF)orhigh
frequency(HF)condensermicrophones.

12. Condenser Mic
Condensermicrophonesspantherangefromtelephone
transmittersthroughinexpensivekaraokemicrophonesto
high-fidelityrecordingmicrophones.Theygenerallyproduce
ahigh-qualityaudiosignalandarenowthepopularchoice
inlaboratoryandrecordingstudioapplications.
Theyrequireapowersource,providedeithervia
microphoneinputsonequipmentasphantompowerorfrom
asmallbattery.Powerisnecessaryforestablishingthe
capacitorplatevoltageandisalsoneededtopowerthe
microphoneelectronics
Avalvemicrophoneisacondensermicrophonethatuses
avacuumtube(valve)amplifier.Theyremainpopularwith
enthusiastsoftubesound.
https://www.google.com/url?sa=i&url=https%3A%2F%2Fpixabay.com%2Fphotos%2Faudio-condenser-
microphonemusic1844798%2F&psig=AOvVaw0G424TmxJGRsc_ZIayabXC&ust=1592049123048000&so
urce=images&cd=vfe&ved=0CAIQjRxqFwoTCPCKpLCb_OkCFQAAAAAdAAAAABAD

13. Parts in a Condenser Mic
1.Sound waves
2.Diaphragm
3.Back plate
4.Battery
5.Resistor
6.Audio Signal

14. Ribbon Mic
Ribbonmicrophonesuseathin,usuallycorrugated
metalribbonsuspendedinamagneticfield.The
ribboniselectricallyconnectedtothemicrophone's
output,anditsvibrationwithinthemagneticfield
generatestheelectricalsignal.Ribbonmicrophones
aresimilartomovingcoilmicrophonesinthesense
thatbothproducesoundbymeansofmagnetic
induction.

15. Parts of a Ribbon Mic
1.Sound Waves
2.Magnet
3.Ribbon
4.Audio Signals
Ribbon Material

16. Microphones
Characteristics
Design
Applications
Techniques
Directional Patterns.

17. Characteristics
Impedance
Frequency Response
Sensitivity
Polarity
Connector
Phantom Power
Wireless/Wired

18. Impedance
Impedancemeasurestheamountofoppositiona
devicehastoanACcurrent.TheUnitofImpedance
isohmsandisrepresentedwiththeGreekomega
symbolΩ.
Allmicrophoneswillberatedwithanimpedance,
thismaybewrittenonthemicrophoneitselforon
thespecificationsheetofmicrophone.Thetwo
generalclassificationsformicrophoneimpedance.
LowImpedance200-1000Ω
HighImpedance10k–50kΩ

19. Frequency Response
TheFrequencyresponsereferstothewaya
microphoneactinresponsetodifferentfrequencies.It
isthefeatureofallmicrophonesthatsome
frequenciesareembellishedandothersare
attenuated.Afrequencyresponsewhichfavorhigher
frequenciesmeansthattheresultingaudiooutputwill
havemorehigherendfrequencies(Treble)thanthe
originalsound.

20. Frequency Response

21. Sensitivity
Microphonesensitivityismeasuredwitha1kHzsine
waveat94dB(SPL).
Sensitivity,theratiooftheanalogoutputvoltageor
digitaloutputvaluetotheinputpressure.
Theamountoftheanalogordigitaloutputsignal
fromthemicrophonewiththatinputstimulusisa
measureofitssensitivity.

22. Sensitivity
Image Source : https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.learningaboutelectronics.com%2FArticles%2FWhat-is-microphone-
sensitivity&psig=AOvVaw3XsIjuadEbYYesh6HX8WN&ust=1592397859717000&source=images&cd=vfe&ved=0CA0QjhxqFwoTCKCWtbuuhuoCFQAAAAAdAAAAABAJ

23. Polarity
Polarity,whenitcomestorecording,meanshaving
thespeakermoveinthesamedirectionthat
themicmembraneoriginallymoved.Forexample,
ifyouputamicinfrontofakickdrumandthe
drummerplaysthekick,theheadinitiallymoves
towardthelistenerinfrontofthedrum.
For More Info Visit:
https://www.sweetwater.com/insync/polarity-does-it-really-
matter/#:~:text=Polarity%2C%20when%20it%20comes%20to,in%20front%20of%20the%20drum.

24. Polar Patterns (Directional response)
Amicrophone'sdirectionalityorpolarpattern
indicateshowsensitiveitistosoundsarrivingat
differentanglesaboutitscentralaxis.Howthe
physicalbodyofthemicrophoneisorientedrelative
tothediagramsdependsonthemicrophonedesign.
Somemicrophonedesignscombineseveral
principlesincreatingthedesiredpolarpattern.This
ranges from shielding (meaning
diffraction/dissipation/absorption)bythehousing
itselftoelectronicallycombiningdualmembranes.
Video

25. Polar Patterns (Directional response)
OMNI-DIRECTIONAL
AnOmni-directional(ornon-directional)
microphone'sresponseisgenerallyconsideredtobe
aperfectsphereinthreedimensions.(360)
Image Source: https://www.shure.eu/musicians/discover/educational/polar-patterns

26. Polar Patterns (Directional response)
CARDIOID
Aunidirectionalmicrophoneisprimarilysensitivetosounds
fromonlyonedirection.Themiccutoffunwantedambient
soundandgivesmuchmoreresistancetofeedbackthanomni
directionalmicrophones.Thismakesacardioidmicrophone
appropriateforlivereinforcement.
Image Source: https://www.shure.eu/musicians/discover/educational/polar-patterns

27. Polar Patterns (Directional response)
BIDIRECTIONAL
"Figure8"orbi-directionalmicrophonesreceivesoundequallyfromboth
thefrontandbackoftheelement.Mostribbonmicrophonesareofthis
pattern.Inprincipletheydonotrespondtosoundpressureatall,onlyto
thechangeinpressurebetweenfrontandback;sincesoundarrivingfrom
thesidereachesfrontandbackequallythereisnodifferenceinpressure
andthereforenosensitivitytosoundfromthatdirection.
Image Source: https://www.shure.eu/musicians/discover/educational/polar-patterns

28. Other Polar Patterns (Directional
response)
Hyper-cardioid
Super-cardioid
Sub-cardioid

29. Polar Patterns (Directional response)
Ahyper-cardioidmicrophone is similar to cardioid,
but with a slightly larger figure-8 contribution,
leading to a tighter area of front sensitivity and a
smaller lobe of rear sensitivity.

30. Polar Patterns (Directional response)
Asuper-cardioidmicrophoneissimilartoahyper-
cardioid,exceptthereismorefrontpickupandless
rearpickup.Thisratiomaximizesthefront-back
ratio;theenergyratiobetweenfrontandrear
radiation.

31. Polar Patterns (Directional response)
Thesub-cardioidmicrophone has no null points. It is
produced with about 7:3 ratio with 3–10dB level
between the front and back pickup.

32. A Quick Comparison
Image Source: https://www.shure.eu/musicians/discover/educational/polar-patterns

33. Application-specific designs
Alavaliermicrophoneismadeforhands-free
operation.Thesesmallmicrophonesarewornonthe
body.Originally,theywereheldinplacewitha
lanyardwornaroundtheneck,butmoreoftenthey
arefastenedtoclothingwithaclip,pin,tapeor
magnet.Thelavaliercordmaybehiddenbyclothes
andeitherruntoanRFtransmitterinapocketor
clippedtoabelt(formobileuse),orrundirectlyto
themixer(forstationaryapplications).

34. Contact microphone
Acontactmicrophonepicksupvibrationsdirectlyfroma
solidsurfaceorobject,asopposedtosoundvibrations
carriedthroughair.Oneuseforthisistodetectsounds
ofaverylowlevel,suchasthosefromsmallobjects
orinsects.Thecontactplateisplaceddirectlyonthe
vibratingpartofamusicalinstrumentorothersurface,
andthecontactpintransfersvibrationstothecoil.
Contactmicrophoneshavebeenusedtopickupthe
soundofasnail'sheartbeatandthefootstepsofants.
Aportableversionofthismicrophonehasrecentlybeen
developed.
More Info : https://youtu.be/dxsmpbgONU8
https://youtu.be/MRpjsQp7-9I

35. Throat microphone
Athroatmicrophoneisa
variantofthecontact
microphonethatpicksup
speechdirectlyfroma
person'sthroat,whichitis
strappedto.Thisletsthe
devicebeusedinareas
withambientsoundsthat
wouldotherwisemakethe
speakerinaudible.

36. Parabolic microphone
Aparabolicmicrophoneusesaparabolic
reflectortocollectandfocussoundwaves
ontoamicrophonereceiver,inmuchthe
samewaythataparabolic
antenna(e.g.satellitedish)doeswith
radiowaves.
Typicalusesofthismicrophone,whichhas
unusuallyfocusedfrontsensitivityandcan
pickupsoundsfrommanymetersaway,
includenaturerecording,outdoorsporting
events,eavesdropping,lawenforcement,
andevenespionage.

37. Wireless microphone
Awirelessmicrophonetransmitstheaudioasa
radiooropticalsignalratherthanviaacable.It
usuallysendsitssignalusingasmallFMradio
transmittertoanearbyreceiverconnectedtothe
soundsystem,butitcanalsouseinfraredwavesif
thetransmitterandreceiverarewithinsightofeach
other.

38. Noise-canceling microphone
Anoise-cancelingmicrophoneisahighlydirectional
designintendedfornoisyenvironments.Onesuchuse
isinaircraftcockpitswheretheyarenormally
installedasboommicrophonesonheadsets.Another
useisinliveeventsupportonloudconcertstagesfor
vocalistsinvolvedwithliveperformances.
Manynoise-cancelingmicrophonescombinesignals
receivedfromtwodiaphragmsthatareinopposite
electricalpolarityorareprocessedelectronically.A
fewnoise-cancelingmicrophonesarethroat
microphones

39. Stereo microphones
A stereomicrophone
integratestwomicrophonesin
oneunittoproducea
stereophonicsignal.Astereo
microphoneisoftenused
forbroadcastapplications
orfieldrecordingwhereit
wouldbeimpracticalto
configuretwoseparate
condensermicrophonesina
classicX-Yconfiguration
(seemicrophonepractice)for
stereophonicrecording.Some
suchmicrophoneshavean
adjustableangleofcoverage
betweenthetwochannels.

40. MCQs / Assessment
Multiple Choice Questions Link will be shared in
Quizziz.com
Model Question :
What is the operating principle of a transducer in Moving Coil
Microphone?
a) Electromagnetic Induction b) Electrostatic Principle
c) None of the Above d) Both a & b

41. Summary
Microphonesaredevicesthatareusedfor
recordingsoundsforvariousapplication.Theyare
mainlyof3types,Dynamic,Ribbonand
Condenser.Themaincharacteristicsofmicrophones
areitsimpedance,frequencyresponse,polarity,
sensitivityanddirectionalresponse.
Microphonesareusedfordifferentkindof
applicationsaccordingtotheirtype,design,and
polarpatterns.

42. Points to Remember
Microphoneisatransducerthatconvertsacoustical
energytoelectricalenergy.
Microphonesareofdifferenttypes:its
differentiatedaccordingtoitsdesign,polar
response,makeandcharacteristics.
Therearethreemaintypeofpolarpatterns:
Unidirectional,bidirectionalandomni-directional.
Application-specificmicrophonesareusedfor
specificpurposesofrecording.

43. Source for Reference
https://www.shure.eu/musicians/discover/education
al#!page-teaser-782efe2c#all
https://www.shure.eu/musicians/discover/education
al/microphone-directionality-polar-pattern-basics
https://www.shure.eu/videos/events/webinars/shur
e-webinar-microphone-techniques-for-mobile-
recording

44. Introduction of Next Session
Loudspeakers
Loudspeaker Types and Design
Application
Parts of Loudspeaker
Crossover

45. Thank You
SANKARANARAYANAN K. B
ASST. PROFESSOR
DEPARTMENT OF VISUAL COMMUNICATION
NEHRU ARTS AND SCIENCE COLLEGE(Autonomous)
COIMBATORE
Mail Id: [email protected]