All language subtitles for Electrical Audio How-To Microphone Techniques for Speaker Cabinets

how badly did i whack that up

hi i'm steve albini and today we're

going to be talking about miking speaker

cabinets

one of the first things you need to

decide when you're putting a microphone

on a cabinet

is physically where to place the

microphone that is

what part of the speaker you're going to

be pointing at and

what distance you're going to be working

from so

considering the placement of the

microphone across the face of the

speaker

the center of the speaker cone is going

to be moving

in and out of the magnetic gap the most

accurately that is

it's going to be the most tightly

controlled by the mag electromagnetic

effects

and the movement of the center of the

speaker is going to be the most accurate

representation of the input signal

as you move out toward the perimeter of

the speaker there are a lot of other

effects that creep in

the speaker itself can ripple or crumple

there can be a harmonic mode generated

around the perimeter of the speaker

the mechanical installation can cause

noise or damping

all of those things argue that the

perimeter of the speaker is going to be

a less accurate representation of the

input signal

than the center of the speaker and all

of those things argue for pointing the

microphone toward the center of the

speaker

now those things those irregularities

do contribute to the sound quality of

the cabinet and the speaker overall when

you're listening to a

loudspeaker you're typically listening

at a distance

so if the guitar player is fond of their

guitar sound

that normally means that they've been

hearing it at a distance and they like

the sound of it at a distance

so to capture that sound

that argues for backing the microphone

off from the loudspeaker slightly

there's an added benefit to that when

the microphone is very close to the

loudspeaker

it's hearing all of these eccentricities

at their most at their highest level and

also the microphone can be exaggerating

one or more of these eccentric sound

effects there are also internal cabinet

reflections that is where the sound is

bouncing around inside the cabinet

and where the sound is bouncing off of

the mechanical frame of the speaker

and those short reflections create comb

filtering effects and can

dull the sound quality as you move away

from the loudspeaker

all of those effects sort of sum

into a general cabinet sound that is the

sound of the cabinet as

at a distance is where all of those

effects have combined

and summed into a single sound which you

can identify as the sound quality of

that speaker

so if you're trying to capture the sound

quality of a specific speaker cabinet

my default is to start with the

microphone at the center of the speaker

and then back it off to a distance where

i can hear with my ear

that the effects of the local

resonances and oddities of the cabinet

have sort of combined

into a single sound that translates to a

working distance typically of 12 to 14

inches for a guitar cabinet

for a smaller amplifier system like a

small combo amplifier

the working distance can be a bit closer

let's go into studio a and i'll show you

how i set a microphone up on a

loudspeaker

so this is the amplifier that i want to

put a microphone on

i put it up on this chair so that it

will be

closer to the working height of the

microphone stands and i won't have to

stoop so much

and whenever i do that i like to secure

a small amplifier with a strip of gaffer

tape on the front and back of the

amplifier

so that the working vibration of the

amplifier doesn't cause it to move off

axis from the microphone

the first thing i need to do is figure

out where the center of the speaker cone

is if i'm going to put the microphone in

front of it

a couple of ways to do that if you put

your hand around the back of the small

amp like this you can feel the center of

the magnet

on the back of the speaker and if you

point your finger there

you can put your finger in a

corresponding position on the front

opposite that other finger

and that'll find the center of the

speaker you can also just look through

the grille but

if you can't see through the grille you

can use a light like the one on your

cell phone

which will show you precisely where the

center of the speaker is and once you've

found the center of the speaker you'll

know where to put your microphone

now this microphone is going to be at a

working distance and it can be difficult

to tell

at a working distance whether you're on

the center line of the speaker or not

so what i like to do is i like to bring

the microphone right up close

line it up with the center of the

speaker and once i'm certain that it's

lined up i can move it back along that

axis to any working distance

now this mic stand is all is adjusted

all the way to the bottom

and it might seem that i wouldn't be

able to get this microphone in front of

the center of the speaker

but there's an extra little adjustment

here this screw which is normally used

to collapse the mic stand for storage

if you loosen that you can lower the

center post of the mic stand

and get even a big microphone like this

down in line with the center line of the

speaker

now that i'm centered on the speaker i

can move this back to any working

distance

oh wait a minute one more thing

the working distance of the microphone

can have a tremendous effect on the

sound quality

you can use this to your advantage to

improve the sound quality

of a thin or weak sounding amplifier for

example

you can take advantage of a principle

called the proximity effect

all microphones exhibit this

characteristic some more than others

but at a closer working distance you

tend to get more low frequency response

that's the proximity effect figure eight

microphones

tend to have more proximity effect than

directional microphones

omnidirectional microphones have the

least proximity effect

so as the microphone gets closer to the

loudspeaker

it exaggerates the low frequencies and

if the mic if the amplifier sounds kind

of weak

kind of thin then you can beef it up

slightly by using a microphone with a

greater proximity effect the microphones

with the greatest proximity effect are

those

that are in a physically large housing

as the microphone gets close to the

loudspeaker

the polar pattern is created by the

sound striking the front of the loud

front of the microphone and some of the

sound traveling around

to the back of the microphone and the

interference of those two is what

creates the polar pattern of the

microphone

if the microphone is in a physically

large housing that is if it's a ribbon

microphone with a large magnetic

armature

then the sound gets to the front of the

microphone the working element

fairly quickly but it has a relatively

long

distance to travel to get around to the

back of the microphone

that tends to make the rear pattern

less in as the

microphone gets closer that is

microphones tend to lose their

directional qualities the closer they

get to the sound source

and it also tends to exaggerate the

proximity effect

so for the greatest proximity effect you

would use

a bi-directional microphone say a ribbon

microphone

with a large magnetic armature that is a

large footprint

because that would make for the the

greatest acoustic

shadow and the most exaggerated

proximity effect

let's go back into the studio and i'll

show you some more useful microphone

techniques

a normal working distance for me for a

cabinet like this

would be 12 to 14 inches something

like that if i wanted to emphasize the

low frequencies using the proximity

effect

to make this amplifier sound bigger or

heavier i can choke the microphone

right up on top of the speaker

proximity effect on a small combo amp

[Music]

no

okay this is a bass amplifier

uh in this instance it's for a bass

guitar but it could be

for an electric keyboard uh an organ

a electric piano or rhodes a wurlitzer

synthesizer any of those instruments

that needs a good bass response you

could be using a bass amplifier for live

monitoring

with any of those instruments it's

important to record the lowest

frequencies

with accuracy so i tend to use a

microphone like this the buyer m380

it's a microphone with good low

frequency response but it's also a

figure eight microphone

so i can move it very close to the

speaker and take advantage of the

proximity effect to extend the low

frequency response

so this microphone is going to be very

heavy in low frequencies

and i can be certain that even the

lowest notes are going to be accurately

recorded

now there is high frequency detail

coming out of the amplifier as well and

if you lose that information you can

lose the articulation of the notes

so i tend to also use a brighter

microphone like this

the sennheiser 421 and record them

simultaneously with their diaphragms

aligned so they stay in phase

then in the control room i can balance

these two microphones against each other

and synthesize the most accurate

representation of the speaker

you can think of it as something like

the woofer and tweeter in a hi-fi

speaker

where you have one driver that's

covering the low frequencies and another

one that's covering the high frequencies

and the blend of the two of them gives

you the most accurate representation

buyer m380 low frequency response at

close distance

[Music]

sennheiser 421 high frequency detail

[Music]

both mics

[Music]

ah

is a little tiny amplifier

this is a ribbon microphone the stc 4038

with a figure eight pattern and a large

armature

so it will exhibit the proximity effect

and the acoustic shadowing that i

described earlier

at a normal working distance this

microphone will be picking up the guitar

from the front lobe but the rear lobe

will be

picking up the free field ambient sound

of the room

so if i want a more ambient sound off of

this signal

i can just move this microphone back the

front

lobe will still be picking up the direct

signal of the mic of the amplifier

but the rear lobe will be picking up

relatively more of the ambient sound in

the room

so you have a great deal of flexibility

with the placement of a microphone like

this

changing the character of the sound if i

bring it up close

the acoustic shadow and the proximity

effect will exaggerate

the bass response of the amplifier

making this small amplifier sound bigger

at a normal working distance i'll get an

accurate representation of the sound of

this amp

and if i move the microphone a little

farther back i'll be using

more of the rear lobe of the microphone

and less of the front lobe and i'll get

a more ambient sound

[Music]

so

[Music]

so

[Music]

i blew that my performance

this is a bigger cabinet with two

speakers with multiple speakers in it

and that gives you the option of using

multiple microphones on different

speakers

the speakers themselves might be

different with different sound qualities

and you may want to record them

separately or you may want to take

advantage

of different sound quality microphones

either for balancing

later or to synthesize a stereo image

from a mono signal

in this case i have a ribbon microphone

here and a condenser microphone here

the ribbon microphone will be slightly

darker slightly heavier the condenser

microphone will be slightly brighter

slightly

slightly more high energy more high-end

energy

anyway i've also got a microphone at a

distance picking up the ambient sound in

the room

that microphone is over there by the

conga drum

i have this microphone on the floor so

that its pickup pattern

normally omnidirectional becomes

hemispherical that is it's picking up

the reflected sound from all the

surfaces in the room

above the floor it's not hearing any of

the reflections off of the floor

those would be near field reflections

which would cause coloration of the

sound

it's a good practice when you're putting

a microphone on the floor to put a stand

or get

or some piece of hardware over the top

of the microphone

acoustically it's basically transparent

but it prevents people from stepping on

the microphone accidentally

[Music]

[Applause]

[Music]

ah

a combo amplifier like this ac 30 or a

fender twin

sometimes has two speakers now you can

record those two speakers independently

or you can record one of them

but if what you're after is the overall

sound of that amplifier

at a at some distance away from those

two speakers

the sound of them sums into a phantom

center

that is if you're close very close to

the cabinet you can hear the two

speakers discreetly

but if you back up just a little bit

you'll find a point where

between midpoint between those two

speakers you're hearing both speakers

and the whole of the cabinet

from a single point that phantom center

is a good place to put a microphone if

you want to use one microphone to pick

up that amp

you can find that center by crouching

down and moving your head back and forth

and you will be able to hear very

clearly the point at which all the sound

from the cabinet sums to a single point

and that's how you know where to put

this microphone

i'm not going to do the jumping thing

that started to hurt

after a while okay you may have noticed

that in these

demonstrations the microphone position

relative to the speaker cabinet

is and on that is the

plane of the speaker cabinet

is parallel to the plane of the

microphone diaphragm

when i first started working i didn't

know what i was doing

and so i mimicked the practices of other

people that i'd observed

and it was a very common practice for

a speaker cabinet to be mic'd from the

side with the microphone coming in at an

angle

if this is an overhead view of the

cabinet

the microphone would be very close to

the speaker and

sort of angled in from the side

and when i tried that mic position i

found it unsatisfying

it didn't sound that clear i felt like i

was

uh reaching for the equalizer often

and i started to think about why it

didn't sound that good

and experimenting in with moving the

microphone position and i found that

when i had the microphone

more perpendicular the sound was

instantly brighter and clearer and

sounded better to me

um and if you imagine the

the plane of the speaker

emanating sound this away

and if the microphone is at an angle

then the angled diaphragm of the

microphone

is going to be getting

sound across it at slightly different

times

and that's going to cause some phase

cancellation and the very high

frequencies

uh and indeed i noticed that when i had

the microphone at an

at an angle it sounded duller and less

precise to me

but if the microphone is perpendicular

to the plane of the speaker

then you know within a very small error

the whole of the diaphragm is being hit

by the sound at the same time

um and i believe this practice was

derived

from um live sound engineers having to

keep the stage uncluttered in front of a

speaker cabinet

um the area in front of the speaker

cabinet is prime real estate for

dancing and other kinds of showmanship

uh

you know whatever people do on stage

i've never been on stage so i don't know

rather than put a microphone out in the

middle of the stage where it could get

kicked

live sound engineers developed the

practice of having the microphone off to

the side of the speaker cabinet

and then sneaking it in at an angle so

as a kind of a defensive

maneuver and then that just survived as

received wisdom

into the studio

and all of my practices in the studio

are derived from an iterative

experimental process

i would try something and if it didn't

sound good i would try to think about

why it didn't sound good and that would

guide future experimentation and until

eventually

i developed a set of practices that i

think

are durable and versatile and can be

used in a lot of different situations

i encourage everybody to experiment with

their studio practices

because that's how the

profession grows and

matures we get better at things over

time

because we're bad at them at some point

and we stop doing that

you