Microphones

How they work!

• Microphones transduce sound waves into electric energy – the audio signal

Sound Pickup - directionality

• Omnidirectional• Unidirectional

Omnidirectional

• Hears well in ALL directions

Unidirectional

• Hears well from ONE direction

Unidirectional

• Cardioid – in front of and to the sides

Unidirectional

• Hypercardioid – in front of and long distance; shotgun mic

How are Mics Made?

• 3 types– Dynamic– Condenser– Ribbon

Dynamic

• Small coil in a magnetic field.• Movement of coil produces sound signal.

Dynamic Facts

• Most rugged• Handles loud sounds• Built in pop filter• Can withstand all weather• Can withstand occasional rough handling

Condenser

• Moveable plate (diaphragm) oscillates against a fixed plate

Condenser Facts

• Sensitive to physical shock• Sensitive to temperature• Generally used indoors• Prominent in music recording• Needs a power supply– Some have battery in housing– Some draw phantom power

Ribbon

• A tiny ribbon in a magnetic field

Ribbon Facts

• Highly sensitive• Used in audio-recording studios• Normally used to record string instruments• Too sensitive for video work

How Mics Are Used

• Proper positioning of mic to relative sound source is more important than what kind of mic it is. So mics are often identified by how they are used.

Mics

• Lavalier• Handheld• Boom• Desk/Stand• Headset• Wireless(radio)

Lavalier Facts

• Very small• Rugged• Omnidirectional• Primarily used for voice• Clipped to clothes• Good quality

Handheld Facts

• Used when talent needs to control sound• Handled by talent

Boom Facts

• Used to keep mic out of picture• Suspended from fishpole or big boom• Usually super- or hyper-cardioid shotgun mic

Desk/Stand Facts

• Handhelds mounted on stands• Used for performers in a fixed position

Headset Facts

• Used by sportscaster or talent announcing live events

• Combines headset with mic and earphones that carry split audio– Program sound in one ear– Production instruction in other ear

Wireless (radio) Facts

• Broadcast signal from transmitter to receiver• Most popular handheld for singers

Lavalier Advantages

• Talent is hands-free• Distance from mic to source doesn’t change• No special lighting concerns• Talent has freer movement

Lavalier Disadvantages

• Can’t move mic closer to mouth in noisy situations

• Need separate mic for each sound source• May pickup clothing rubbing sounds• Sound perspective can be messed up

Handheld Advantages

• A talent can move mic closer to mouth• Talent can point it at person speaking• Need only a single mic for multiple sources• Singer can control intimacy of sound

Handheld Disadvantages

• Inexperienced talent may block faces• Talent may aim mic incorrectly• Talent’s hands aren’t free

Boom Advantages

• Mic can be aimed at main sound• Picks up sound from a distance

Boom Disadvantages

• Can have noisy handling if not attached properly

• Long fishpoles are heavy & difficult to handle• Must have a long enough mic cable• Boom may cast unwanted shadows• Studio boom is large and take up space• Operating a boom is as difficult as operating

the camera

Desk/Stand Advantages

• One mic can pickup multiple sources• Quality of mics on stand can vary depending

on use of mic

Desk/Stand Disadvantages

• People are less careful– Use omnidirectional and dynamic

• User may pull mic to them after careful placement

Headset Advantages

• Hands free• Can hear director instructions• Can hear program audio

Headset Disadvantages

• Useful in only a few applications– Sports– Live events

Wireless(radio) Advantages

• Performer unrestricted by cable• Wireless lav can be used to pickup nat sound

(ex. Bicyclist)

Wireless (radio) Disadvantages

• Signal pickup depends on talent’s relationship to receiver

• Can pickup interference from other wireless devices