Multimoog Musical Instrument Wartungshandbuch PDF herunterladen (Seite 21)

Now

we

can route

control

signals

into

the

con

trol

input

of

each

module

shown

above

to

dynami

cally

control

its

function.

Think

of

a

control

signal

fed

into

the

control

input

as

acting

like

an

invisible

hand

that

turns

the

knob

for

you.

Voltage

controlled

modules

are

sometimes

referred to

with

letters,

such

as

VCO

(voltage

controlled

oscillator),

VCF

(voltage

controlled

filter),

and

VCA

(voltage

controlled

amplifier).

Although

any

number

of

modules

may

be

voltage

controlled,

these

are

the

most

common—

VCO,

VCF,

VCA.

Anything

that

makes

a

proper

signal

that

is

connected

to

a

control

input

is

defined

as

a

controller.

On

a

modular

synthesizer,

the

output

of

a

controller

would be

connected

to

the

control

input

of

a

module

with

a

patchcord

as

shown:

CONTROLLER—CONTROL

INPUT

CONNECTION

VCO

CONTROLLER

CONTROLLER

VCF

VCA

CONTROLLER

J

TO

MONITOR

On

the

Multimoog,

control

signals

may

be

connected

to

control

inputs

using

a

variety

of

switches

and

selectors.

Or

a

control

signal

from

the

outside

world might

be

routed

through

the

FILTER

or

OSC

A&B

INPUT

on

the

rear

panel.

Each

control

input

on

the

Multimoog

is

capable

of

adding

all

of

the

voltages

that

are

applied

from

several

controllers;

that

is,

control

voltages

are

additive.

A

keyboard

is

a

controller

that

makes

discrete

voltage

steps

which

increase

as

you

play

up

the

key

board.

If

this

controller

is

connected

to

the

control

input

of

the

VCO,

the

keyboard

can

be

used

to

control

the

pitch

of

the

VCO

and

tunes can

be

played.

A

contour

generator

is

a

controller

that

creates

a

rising

and

falling

voltage

pattern,

a

contour.

If

we

connect

this

controller

to

the

control

input

of

the

VCA,

the

amount

of

amplification

(silence

to

maximum)

will

be

controlled.

This

lets

us

articulate

the

sound.

The

VCF

can

also

be

controlled

by

a

contour

generator.

When

this

occurs,

the

tone

color

will

typi

cally

become

brighter

as

the

contour

voltage

rises,

and

duller

as

it

falls.

To

get

back

to

our

comparison

with

the

trumpet,

suppose

that

you

were

using

a

Harmon

mute.

As

you

move

your

hand

away

from

the

plunger

in

the center

of

the

mute,

you

create

the

familiar

"wow"

or

"wah-wah"

effect.

Your hand

is

acting

as

a

contour

generator,

controlling

the

filter

(mute).

Of

course,

we

have

to

tell

a

contour

generator

when

to

start

and

stop

creating

contours.

For

this

purpose,

the

synthesizer

produces

another

type

of

signal

called

a

"trigger."

The

keyboard

generates

a

trigger

signal

that

tells

when

a

key

is

depressed

and

released—useful

information.

A

trigger

is

a

timing

signal

that

"triggers"

the

contour

generator(s).

(On

some

modular

equipment,

other

functions

can

be

"triggered.")

I

n

summary,

the

modern

synthesizer

consists

of

several

elements:

sound

sources,

modifiers,

control

lers,

and

trigger

sources.

Sound

sources

make

audio

signals

that

can

be

heard.

Modifiers

alter

signals.

Con

trollers

make

signals

used

to

control

sound

sources

and/or

modifiers.

Triggers

are

timing

signals

that

usually

initiate

the

action

of

a

controller

such

as

a

contour

generator.

See

below

for a

block

diagram

of

the

basic

voltage

controlled

synthesizer.

26

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 76 77

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