audio production chapter 4 pt 1

what is the signal chain?

everything used in the system

microphones take ___ and transduces it into ___

kinetic energy, electrical audio signal

the three different types of microphone

dynamic, condenser, ribbon

when conductive metal moves through a magnetic field, what happens?

electricity is made

dynamic mics uses __ to transduce sound to _

electromagnetic induction, audio signal

the dynamic mic is able to transduce sound because of its __

voice coil

voice coil

a wire attached to a thin plastic diaphragm

the voice coil moves around the __ when _

magnet, changes in air pressure push and pull on the diaphragm

because the voice coil is made of conductive metal..

moving through the magnetic field generates electricity

greater air pressure received by dynamic mics translates to

more voltage in the signal

the higher the frequency picked up by a dynamic mic..

the faster the diaphragm moves, resulting in faster changes in the electrical signal

because of their construction, dynamic mics are

more durable

dynamic mics emphasize

mid-range frequencies

compared to other mics, dynamic mics freq response is

less flat

dynamic mics can handle

very loud sound

dynamic and ribbons mics do not require

phantom power

like dynamic mics, ribbons mics also _

work electromagnetically

instead of a voice coil, ribbons mics have

a thin strip of super thin aluminum that’s corrugated

the ribbon in a ribbon mic is

suspended in a strong field of magnetic field

picked up by ribbon mics, sound pressure variations cause and cut across and creates ____.

movement, magnetic flux lines, generate electricity

because of the way ribbons mics are constructed, they produce

warm sound

ribbons don’t pick up ___ very well

high frequencies

ribbon mics are extremely

delicate

phantom power ___ ribbon mics

melts

ribbons mics can be more ___ than a dynamic mic, but are not ___ than a condenser

accurate

condenser mics are the most __ mics

accurate

the smaller the capsule in a condenser, the more

accurate

condenser mics operate on an

electrostatic principal

the capsule of a condenser mics consists of

a very thin movable diaphragm and one fixed backplate

the diaphragm and backplate form a ____, which is a ___

capicitor, device that stores electricity

in a condenser mic, phantom power creates

a charge between the diaphragm and back plate

When sound moves the diaphragm, it changes the

capacitance of the capsule

what is capacitance?

a device’s ability to store electricity

Louder sounds result in

higher voltage levels

because of their construction, condenser mics are the

most accurate mics

condenser mics freq response is

flatter than ribbons and dynamics

because a condenser mic has less room for vibration, it

returns to a zero state faster

condenser mics are more ___ than ribbons and dynamics

sensitive

unlike dynamics, condenser mics easily

overload from loud sound

condenser mics require

phantom power

condenser mics are not as __ as dynamics

durable

what is a mics directional response?

a mics ability to pickup sound from some directions and not from others

on axis

the direction a mics most sensitive to sound

off axis

the angles a mic is least sensitive to sound

polar pattern

a graph that shows how well a mic picks up sound from all angles

pickup patterns are the same as

polar patterns

directional response is measured in a __ around the mic

full circle

0 degrees is considered

an axis

bidrectional mics are both

0 and 180 degrees

cardioid patterns

picks up sound in a heart shape in mics front and rejects sound more towards its back

hyper-cardioid patterns

picks up sound in a narrower heart shape area in front of the mic and has a small area of sensitivity to the rear

directional patterns

picks up sound from the front and rear and rejects sound from the sides

directional patterns are also called

figure 8 patterns

directional pattern mics are

bidirectional

true ribbon mics are

bidirectional

omnidirectional patterns

picks up sound from all directions

microphone freq response

the ability of a microphone to pass frequencies through itself in comparison to the frequencies in the sound wave

if all freqs pass through a mic at the same relative levels as the sound wave, then the mic has a

flat freq response

transient response

how quickly and accurately a microphone can react to a sound

low freq rumble

rumble can be easily transmitted from outside forces to mic

low freq rumbles can be combatted with

low freq roll-off filters, shock mounts

when a directional mic is brought closer to a sound source, more low freq is picked up

the proximity effect is byproduct of making the mic

directional

when does popping occur

when directional mics are exposed to wind/breath blast

popping can be fixed by using

pop-screens

popping can be fixed by turning the mic a little

off axis

off-axis pickup

causes loss of higher freqs from less sensitive side of directional mic

sensitivity

the output of a microphone in volts compared to the input in SPL

equivalent noise

noise created by the microphone itself

overload

distortion from a sound too loud for the mic to handle

impedance

an electrical rating that helps match the output of a microphone to the input of a microphone preamp

impedance is measured in

ohms

poor cables lead to

poor sound quality

Why are mic cables very important links?

because mic level voltage is the lowest level signal we deal with in audio and that makes them easily diminished

balanced vs unbalanced cables

balanced cables have at least three conductors/wires. Unbalanced cables have two wires

Having a third wire in a balanced cable allows

cancellation of interference

the ground cable helps shield

the two conductors from interference

XLR connectors

used to connect microphones to preamp, mixer or interface.

1/4” connecters

used to interface between both professional and semi-pro equipment at line-level

TT (or bantam)

connectors/cables allow balanced lines to be plugged into a patch bay for fast and easy access to the various line-level devices

mic preamps

are gain devices that raise the low output voltage of microphones up to the higher line level voltage

mic pres can be

be built into mixers, interfaces and recording devices,

solid state preamps

are more accurate and can produce much less noise, distortion and coloring than preamps with tubes in their gain stage

tube preamps

create very pleasant even-order harmonic distortion that results in warm tones and coloring that solid state preamps can not produce