chapter 6 microphones. microphones transducer: device that changes one form of energy into another...
TRANSCRIPT
Chapter 6Chapter 6MicrophonesMicrophones
MicrophonesMicrophones
Transducer: device that changes one Transducer: device that changes one form of energy into anotherform of energy into another
Mics and speakers: sound to Mics and speakers: sound to electrical signalelectrical signal
Microphones: typesMicrophones: types
Dynamic: a coil of wire attached to a Dynamic: a coil of wire attached to a diaphragm suspended in a magnetic diaphragm suspended in a magnetic field. field.
Sound waves vibrate diaphragm, coil Sound waves vibrate diaphragm, coil vibrates in magnetic field and vibrates in magnetic field and generates a electrical signal similar generates a electrical signal similar to sound waveto sound wave
Microphones: DynamicMicrophones: Dynamic
Tends to have rougher responseTends to have rougher response Rugged and reliableRugged and reliable Handles heat, cold, and high Handles heat, cold, and high
humidityhumidity Preferred for high SPL: guitar amps, Preferred for high SPL: guitar amps,
drumsdrums If flat response, can take the “edge” If flat response, can take the “edge”
off sounds (woodwinds, brass)off sounds (woodwinds, brass)
Microphones: CondenserMicrophones: Condenser
Sometimes called capacitor micSometimes called capacitor mic 2 parts: conductive diaphragm and metal 2 parts: conductive diaphragm and metal
backplate, spaced very close togetherbackplate, spaced very close together Both charged with static electricityBoth charged with static electricity When sound waves strike diaphragm, it When sound waves strike diaphragm, it
vibrates, varying the spacing between the vibrates, varying the spacing between the platesplates
This variation generates a similar signal to This variation generates a similar signal to incoming sound waveincoming sound wave
Diaphragm mass is lower, responds faster to Diaphragm mass is lower, responds faster to rapidly changing sound waves (transients)rapidly changing sound waves (transients)
Microphones: CondensersMicrophones: Condensers
Condenser mics need external power Condenser mics need external power supply (battery or phantom power)supply (battery or phantom power)
Phantom power: 12 to 48 volts Phantom power: 12 to 48 volts supplied through XLR cablesupplied through XLR cable
Most mixers have a switch to turn on Most mixers have a switch to turn on phantom powerphantom power
Microphones: Condenser Microphones: Condenser traitstraits
Wide, smooth frequency responseWide, smooth frequency response Detailed sound, Extended HighsDetailed sound, Extended Highs Omni type has excellent low-Omni type has excellent low-
frequency responsefrequency response Transient attacks sharp and clearTransient attacks sharp and clear Preferred for acoustic instruments, Preferred for acoustic instruments,
cymbals, studio vocalscymbals, studio vocals Can be miniaturizedCan be miniaturized
Microphones: RibbonMicrophones: Ribbon
Thin metal foil or ribbon is suspended Thin metal foil or ribbon is suspended in a magnetic fieldin a magnetic field
Sound waves vibrate the ribbon in Sound waves vibrate the ribbon in the field and generate a electrical the field and generate a electrical signalsignal
Microphones: RibbonMicrophones: Ribbon
Prized for its warm, smooth tone Prized for its warm, smooth tone qualityquality
Delicate, damaged by temperature Delicate, damaged by temperature and humidity changesand humidity changes
Complements digital recordingComplements digital recording ExpensiveExpensive
Microphones: Polar PatternsMicrophones: Polar Patterns
Polar pattern refers to the way a Polar pattern refers to the way a microphone responds from different microphone responds from different directionsdirections
Graph based on sensitivity measured Graph based on sensitivity measured in decibels.in decibels.
Uni-directional, Omni-directional, Bi-Uni-directional, Omni-directional, Bi-directional (figure-8)directional (figure-8)
Three types of unidirectional patterns: Three types of unidirectional patterns: cardioid, supercardioid, and cardioid, supercardioid, and hypercardioidhypercardioid
Microphones: Omni-Microphones: Omni-directionaldirectional
All around pickupAll around pickup Picks up room reverbPicks up room reverb Not much isolationNot much isolation Low sensitivity to popsLow sensitivity to pops Low handling noiseLow handling noise No up-close bass boost (proximity effect)No up-close bass boost (proximity effect) Extended low frequency response Extended low frequency response
(condensor) great for organ, orchestra, (condensor) great for organ, orchestra, etc…etc…
Lower cost (in general)Lower cost (in general)
Microphone: Omni PatternMicrophone: Omni Pattern
Microphones: Unidirectional Microphones: Unidirectional (cardioid, supercardioid, (cardioid, supercardioid,
hypercardioid)hypercardioid) Selective pickupSelective pickup Rejection of room acoustics, Rejection of room acoustics,
background noise, and leakagebackground noise, and leakage Up-close bass boostUp-close bass boost Better gain-before-feedback in live Better gain-before-feedback in live
soundsound Coincident or near0coincident stereo Coincident or near0coincident stereo
mikingmiking
Microphone: CardioidMicrophone: Cardioid
Broad-angle pickup of sources in Broad-angle pickup of sources in front of micfront of mic
Maximum rejection of sound Maximum rejection of sound approaching the rear of the micapproaching the rear of the mic
Most popular patternMost popular pattern
Microphone: CardioidMicrophone: Cardioid
Microphones: SupercardioidMicrophones: Supercardioid
Maximum difference between front Maximum difference between front hemisphere and rear hemisphere hemisphere and rear hemisphere (good for stage-floor miking(good for stage-floor miking
More isolation than cardioidMore isolation than cardioid Less reverb than cardioidLess reverb than cardioid
Microphone: SupercardioidMicrophone: Supercardioid
Microphone: Hyper-cardioidMicrophone: Hyper-cardioid
Maximum side rejectionMaximum side rejection Maximum isolation – maximum Maximum isolation – maximum
rejection of reverb, leakage, and rejection of reverb, leakage, and background noisebackground noise
Microphone: HypercardioidMicrophone: Hypercardioid
Microphone: Bi-directionalMicrophone: Bi-directional
Also called figure-8Also called figure-8 Front and rear pickup, with sides Front and rear pickup, with sides
rejectedrejected Across table interviews, two-part Across table interviews, two-part
vocals/instrumentalsvocals/instrumentals
Microphone: Bi-directionalMicrophone: Bi-directional
MicrophonesMicrophones
Frequency response varies from Frequency response varies from proximity: off axis colorationproximity: off axis coloration
Off axis coloration: mic will have a Off axis coloration: mic will have a different tone quality on and off axisdifferent tone quality on and off axis
Microphones: Microphones:
Condensers or Dynamics come in all Condensers or Dynamics come in all polar patterns (except bi-directional polar patterns (except bi-directional dynamic)dynamic)
End-addressed or side addressedEnd-addressed or side addressed Switchable polar patterns common Switchable polar patterns common
with side addressed micswith side addressed mics Boundary mics: half pattern (usually Boundary mics: half pattern (usually
omni); rejects room acousticsomni); rejects room acoustics
Boundary MicrophoneBoundary Microphone
Microphones: Frequency Microphones: Frequency ResponseResponse
Range of frequencies a mic will reproduce Range of frequencies a mic will reproduce at an equal level (within a tolerance like at an equal level (within a tolerance like ±3db)±3db)– Most instruments: 80Hz – 15kHzMost instruments: 80Hz – 15kHz– Bass instruments: 40Hz - 9kHzBass instruments: 40Hz - 9kHz– Brass and voice: 80 Hz – 12kHzBrass and voice: 80 Hz – 12kHz– Piano: 40 Hz – 12 kHzPiano: 40 Hz – 12 kHz– Cymbals and some percussion: 300 Hz – 15 or Cymbals and some percussion: 300 Hz – 15 or
20 kHz20 kHz– Orchestra or symphonic band: 40 Hz – 15kHzOrchestra or symphonic band: 40 Hz – 15kHz
Microphones: Frequency Microphones: Frequency ResponseResponse
Roll-off switches: attenuates frequencies Roll-off switches: attenuates frequencies below a point below fundamental below a point below fundamental frequency of instrument you’re recording frequency of instrument you’re recording (guitar does not play below 80 Hz)(guitar does not play below 80 Hz)
Frequency response curveFrequency response curve Presence peak: rising high end around 5 – Presence peak: rising high end around 5 –
10kHz makes sounds more crisp and 10kHz makes sounds more crisp and articulate (crunchy)articulate (crunchy)
Proximity effect: a bass boost tendency of Proximity effect: a bass boost tendency of a mic when placed too close. a mic when placed too close.
Microphones: Other ratingsMicrophones: Other ratings
ImpedanceImpedance Maximum SPL: the point at which a mic Maximum SPL: the point at which a mic
starts to distort – 125db good, 135db better, starts to distort – 125db good, 135db better, 150db excellent150db excellent
Sensitivity: how much output voltage a mic Sensitivity: how much output voltage a mic produces when driven by a certain SPLproduces when driven by a certain SPL
Self-noise: noise level or hiss a mic producesSelf-noise: noise level or hiss a mic produces Signal to Noise Ratio: the difference in Signal to Noise Ratio: the difference in
decibels between mic’s sensitivity and it’s decibels between mic’s sensitivity and it’s self noiseself noise
Microphone typesMicrophone types
Large-Diaphragm CondenserLarge-Diaphragm Condenser– Good low frequency response and low self-noiseGood low frequency response and low self-noise
Small-Diaphragm CondenserSmall-Diaphragm Condenser– Stick shaped or pencil, usually cardioid and end Stick shaped or pencil, usually cardioid and end
addressed, good transient response and detail, addressed, good transient response and detail, good for acoustic instrumentsgood for acoustic instruments
Dynamic InstrumentDynamic Instrument– Stick shaped, end addressed, be careful of Stick shaped, end addressed, be careful of
presence peak, used on drums and guitar ampspresence peak, used on drums and guitar amps
Microphone typesMicrophone types
Live-VocalLive-Vocal– Ice cream cone shaped large grill to Ice cream cone shaped large grill to
reduce breath pops, can be condenser, reduce breath pops, can be condenser, ribbon, or dynamic, usually has ribbon, or dynamic, usually has presence peak and low frequency roll-offpresence peak and low frequency roll-off
Boundary MicBoundary Mic– Used on surfaces like piano lid, wall, Used on surfaces like piano lid, wall,
picks up direct and reflected sound at picks up direct and reflected sound at the same time for smooth responsethe same time for smooth response
Microphone typesMicrophone types
Miniature MicMiniature Mic Stereo Mic: combines two directional Stereo Mic: combines two directional
mic capsules in a single housingmic capsules in a single housing Digital (USB) Mic – built-in a/d Digital (USB) Mic – built-in a/d
converterconverter
Microphone SelectionMicrophone Selection
Natural, smooth tone Natural, smooth tone qualityquality
Flat frequency Flat frequency responseresponse
Bright, present tone Bright, present tone qualityquality
Presence peak (5kHz)Presence peak (5kHz)
Extended lowsExtended lows Omni condenser Omni condenser dynamic with dynamic with extended low extended low frequency responsefrequency response
Extended highsExtended highs condensercondenser
Choosing a MicrophoneChoosing a Microphone
Boosted bass up Boosted bass up closeclose
Directional micDirectional mic
Reduced leakage, Reduced leakage, reduced room reduced room acousticsacoustics
DirectionalDirectional
Enhanced acousticEnhanced acoustic OmniOmni
Miking close to a Miking close to a surfacesurface
Boundry (TMZ)Boundry (TMZ)
Choosing a MicChoosing a Mic
Coincident or near-Coincident or near-coincidentcoincident
Stereo micStereo mic
Extra ruggednessExtra ruggedness DynamicDynamic
Distortion-free pick-Distortion-free pick-up of loud soundsup of loud sounds
Condenser with high Condenser with high SPL spec or dynamicSPL spec or dynamic
Low self-noise, high Low self-noise, high sensitivity, noise-free sensitivity, noise-free pickup of quiet pickup of quiet soundssounds
Large-diaphragm Large-diaphragm condenser miccondenser mic
Mic AccessoriesMic Accessories
Pop Filter: breath pops “p”, “b”, or Pop Filter: breath pops “p”, “b”, or “t” sounds“t” sounds
Stands and boomsStands and booms Shock MountShock Mount SnakeSnake