Yamaha CS-15 User manual

YAMAHA
Synthesizer
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OWNER'S MANUAL
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SYNTHESIZER CS-15
The synthesizer that has brought anew and creative sound to the world of music
is now apopular musical instrument, widely played by music minded people in all
styles ofmusic.
The CS-15 is asuperb synthesizer unexcelled in operation and performance. It is
designed by YAMAHA employing the latest IC technology, and it is destined to be
used by you to explore your own fantastic music universe!
The CS-15 is equipped with 2complete VCO, VCF and VCA systems as well as 2EGs, To
make full use of its functions and to discover your original sound, please read the contents of this
Owner's Manual carefully.
Points of Attention
Installation
Avoid places subjected to direct sunshine, high
humidity, or extremely dusty locations. Never use the
synthesizer near fire or heat-producing objects, such
as on top of apower amplifier.
Cleaning
When cleaning the set, do not wipe the panel or key-
board with thinner or other cleaning liquids, as this
may leave stains or cause discoloration. Always use
only asoft and dry piece of cloth.
Connections
Connections to an amplifier or other equipment must
be made appropriately and with due care, as wrong
connections may lead to damage in the synthesizer
or amplifier.
Volume
The volume level should always be set with care, as
the application of excessive input to the amplifier
may cause damage to the amplifier or speakers.
NOISE
GENERATOR
GLIDE
w[4
TIME VCO 1DEPTH
VCO 2DEPTH
©

CONTENTS
WHAT IS ASYNTHESIZER 4
CONNECTIONS 6
FUNCTIONS
HOWTO PRODUCE SOUND 7
PITCH/GLIDE 8
VCO 9
MIXER/EXTERNAL 10
VCF 11
VCF/VCA 12
EG 13
LFO/EFFECT 14
EFFECT/EXTERNAL 15
CONNECTING TWO SYNTHESIZERS 16
APPLICATIONS
IMPORTANT POINTS 17
HOW TO CREATE THE TRUMPET SOUND 18
USE OF TWO SYSTEMS 20
USE OF EFFECT CONTROLS 21
BLOCK DIAGRAM 22
SOUND MEMO 23
SPECIFICATIONS 25
TROUBLESHOOTING 26
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WHAT IS ASYNTHESIZER
Unlike other musical instruments, the synthesizer has
no fixed sound of its own. Thus, before playing it, it is
necessary to shape the sounds. But with the synthesizer
you will be able to create, with your own hands and by
synthesizing sounds, anew type of sound that can never
be made by any other musical instrument.
•THETHREE ELEMENTS OF SOUND
How does asynthesizer make sounds? Before
explaining the principle of the synthesizer, let us
consider what kind of properties sound has.
Sound produced by musical instruments such as
the piano or the guitar has acertain pitch, according
to the key or string used. It is possible to change the
pitch by changing the length of the vibrating portion
of the string. In this case, the string's number of
vibrations per second also changes. The slower the
string vibrates, the lower the pitch becomes. In this
way, it is possible to express the difference in pitch
by the number of vibrations (frequency).
PITCHES
3<*ss sound
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However, between the sound of apiano and that
of aguitar there is adifference in tone even when
both sounds are of the same pitch: no one will mis-
take the sound of the piano for that of the guitar.
This is because there is adifference in the way the
strings vibrate (the vibration waveform ), due to the
difference in the arrangement by which the sounds
are generated, and because of the difference in the
shape and size of the musical instruments.
TONES JMf«rerK* in -tones means
PIPNO
Furthermore, even when both the pitch and tone
quality are the same there can be adifference in
sound, such as when the same key of the piano is hit
in aforcible or agentle manner. It is easy to discern
the two sounds from each other because of the
magnitude (volume) of the sound. This is because a
difference will be produced in the size and amplitude
of the string's vibrations, due to the intensity with
which it has been struck.
In this way, sounds produced by musical instru-
ments have such elements as pitch, tone and volume,
whose differences add to the sound's characteristics.
These elements are referred to as "the three elements
of sound", which may also be considered as the
difference in frequency, waveform and amplitude.
•TEMPORAL CHANGE IN SOUNDS
However, the elements which render sounds with
certain characteristics are not confined to these
three. Taking the piano for example, the volume will
reach maximum the instant the key is hit, then will
decrease gradually. When the finger is released from
the keyboard, the sound will fade out. In the case of
the organ, the action of depressing the key will cause
the volume to rise to acertain level, which will be
retained for the duration the keyboard is depressed.
The sound will fade away when the finger is released
from the key.
ENVELOPE Veok (owl Envelope
^tr on KEr OFF
In such musical instruments as the trumpet, for
example, the harmonic spectrum changes together
with the change in volume. The tone changes too,
along with the passage of time.
Thus, the sounds of musical instruments undergo
delicate changes from the time the sound is generated
to the time it fades away. These temporal changes are
known as an "envelope."
•HARMONICS
What must we do in order to produce electrical
sounds that have the above mentioned three elements
of sound, these are pitch, tone and volume, and which
vary with time (have an envelope)? Before going into
the matter, let us view sound again from adifferent
angle.
As regards the vibration waveforms by which the
tone is determined, it is known that any given wave-
form can be considered as consisting of acertain
number of sine waves. In other words, all waveforms
can be produced by combining alarge number of
sine waves. For example, let us overlap over asingle
sine wave waveforms having an integral multiple
©

number of vibrations, such as 2-fold, 3-fold, and so
on. It is seen that the waveform will gradually come
to resemble asawtooth waveform. In addition to this,
it is apparent that this sawtooth waveform has a
cycle similar to that of the sine wave that has been
used as the basis. The sine wave with the basic cycle is
referred to as the fundamental and the sine waves of
harmonic overtones as the harmonics. In the case of
musical instruments, the way in which harmonics are
contained in sounds will depend on the arrangement
by which sounds are generated. When we discuss the
difference in tones (waveforms), it is the same as dis-
cussing what kind of harmonics the sounds contain.
Accordingly, one can express the three elements of
sound in another manner, that is, as 1) pitch. 2) the
manner in which harmonics are contained (harmonic
structure) and 3) volume.
SAWTOOTH WOVE
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STRUCTURE OF THE SYNTHESIZER
In the synthesizer, sounds are synthesized by
electronically effecting control on the four properties
of sound (the three elements of sound plus the
envelope), dividing it into 4blocks.
Control of pitch is effected by the VCO, that of
harmonic spectrum by the VCF, that of volume by
the VCA and that of envelope by the EG (envelope
generator). The following describes the functions of
each block.
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In addition to adjusting the cut-off frequency by
means of aknob, the tone is caused to undergo a
temporal change (from the time the sound is
generated to the time it ceases) to give it an "enve-
lope". This is accomplished by effecting control on
the filter's cut-off frequencies by means of the
envelope generator.
VCA
The VCA block adds an "envelope" to the volume.
The process starting from the generation of the sound
up to the point the sound gradually fades away is
governed by the envelope generator's ATTACK TIME,
DECAY TIME, SUSTAIN LEVEL, RELEASE TIME
(A.D.S.R.), changing the amplification degree of the
VCA amplifier.
VCA and Envelope
Storwd -fvam VCF fnuelope VCP\ Output
VCO
The VCO block produces sound sources of fre-
quencies corresponding to the intervals of the key-
board. The sound source waveforms produced by the
VCO are sawtooth waves and square waves that
include many harmonics in aregular manner. These
waves are oscillated, using an electronic circuit.
VCF
The VCF block determines the tone, changing the
harmonic spectrum of the sound sources by cutting,
or emphasizing, certain parts of the harmonics by
passing the sound sources through filters. The
boundary between the portion that passes through
the filter and the portion that is cut off is known as
the cut-off frequency. The VCF creates the charac-
teristic harmonic spectrum, by varying the cut-off
frequency.
The signals from the VCO reach the VCF where
they undergo achange with regard to their harmonic
spectrum by being passed through afilter. The sig-
nals, now containing certain tone characteristics, are
given avolume "envelope" at the VCA and then fed
out. In this way, all elements of the properties of
sound are controlled electronically, by utilizing the
three elements of sound and the "envelope." The
synthesizer has, in addition to the blocks described
above, other blocks such as the LFO which permit
further changes in the sounds. But in this case too,
the job is performed by controlling the three ele-
ments of sound and the envelope.
We hope that the points described in this section
may be helpful to understand the immense possibili-
ties and great pleasure awaiting you on apath that
will lead you into anew world of music using a
totally new musical instrument, the synthesizer. ©

CONNECTIONS
o
HIGH LOW
CONTROL VOLT
r—IN-—|OUT
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VC01 VC02
TT
EG1
(8)
EG2
OUT
9°
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OUTLET
For details of terminals©and©
see page 14.
T
PIN PLUG
STEREO AMPLIFIER (mono,) 9J°^*
terminal.
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ELECTRIC GUITAR
PHONE PLUG
KEYBOARD AMP.
toAUX IN
termina
A4115H
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OPOWER CORD
Connect the power cord plug to an AC outlet.
©OUTPUT
These are output terminals to be connected to the
amplifier. Use the HIGH or LOW level terminal
according to input sensitivity of the amplifier. Con-
nections can be made to akeyboard amplifier, guitar
amplifier, stereo amplifier, etc.
©C0NTR0LV0LT 0TRIGGER
By connecting the set with another synthesizers,
such as CS-5, CS-10*, CS-15, CS-30*, CS-30L*, etc.
having CONTROL VOLT (or KEY VOLT), and
TRIGGER terminals, this set can be used as amulti-
system synthesizer. See page 16 for further details.
*CS-10, CS-30 and CS-30L are not available in certain
region.
•Never apply an excessive input (5V or more) to
the CONTROL VOLT IN terminal, since this will
cause damage to the synthesizer.
OEXTERNAL
By connecting an electric guitar or an electric
piano to this terminal, asynthesizer effect can be
given to such sound sources. For further details see
page 16.
©

functions HOW TO PRODUCE SOUND
The panel layout of the CS-15 is as follows: Two VCO -VCF -» VCA systems are situated
above each other in the center and the blocks controlling these in its vicinity. The thin lines combining
each block indicate the signal flow. First we will merely indicate the basic setting for producing sounds
experimentally to check the synthesizer or amplifier.
This is an example in which triangle waves are generated in one system (upper side) and
square waves in the other system. We will describe this setting first and then go on to explain each block
and the functions of each knob. It is advisable to actually perform these settings and confirm the results
by ear in order to fully understand all functions.
BASIC SETTING
1. Connect the synthesizer properly by referring to
CONNECTIONS on previous page.
2. Set the switches and knobs as illustrated below with
arrow marks.
•Do not use the other knobs yet.
3. This completes the basic setting to produce sounds.
•The knobs and switches have serial numbers
from(T)to @, and are explained under that
number.
®POWER SWITCH
When pushed down, the synthesizer is switched on
and the indicator illuminates.
©VOLUME
This is used to control the overall volume of the
OUTPUT block.
•The volume control on the amplifier and that
of the CS-15 determine the final volume.
®KEYBOARD
The CS-15 covers 3octaves with 37 keys.
When two or more keys are depressed at the
same time, priority will be given to the key of
the higher pitch. The CS-15 is amonophonic
synthesizer with higher-pitch priority.
When keys are depressed in the basic setting,
sounds are produced.
If the INITIAL LEVEL knobs ©and ©
in the VCA block are turned towards 10, sound
can be produced even without keys being de-
pressed. This is convenient for sound experi-
menting purposes. (For ©and ©please
refer to page 12.)

functions PITCH/GLIDE
The PITCH block works on the VCO, controlling the pitch.
•TUNE is effective on both VCO 1and VCO 2, and DETUNE on VCO 2onty.
©TUNE
This knob adjusts the pitch. It controls the pitch
of both VCO 1and VCO 2. If it is turned towards
"plus", the pitch will rise. If it is turned towards
"minus", the pitch will decrease. It is used for tuning
the CS-15 to other instruments.
•After tuning on the synthesizer, the pitch will
fluctuate for some time until the thermal equi-
librium of the electronic circuit is reached.
Thus, tuning should be done appr. 15 minutes
or more after the power switch was turned ON.
®VCO 2DETUNE
Used for adjusting the pitch of VCO 2only.
•Also used to obtain chorus effects by changing
the relative pitch of the two systems only
slightly and to produce harmonic effects by
changing it by afactor of 3, 5, etc. For further
details refer to page 20 where "USE OF TWO
SYSTEMS" is described.
Tuning must be made at the VCO 1output.
The pitch of VCO 2is changed by DETUNE.
GLIDE BLOCK: This block varies the pitch in the attack period when sounds are being produced by de-
pressing of the keys. In musical instruments, volume, tone, and pitch will be varied during the time from
the start of the sound to its fading away. The temporal variations ofvolume and tone are generated by the
EG block but variations of the pitch are generated by the GLIDE circuit
®TIME
This controls the time until the constant pitch
corresponding to the intervals of the keys is reached.
The further towards Lthe knob is turned, the longer
is the time.
®VCO 1DEPTH
This knob adjusts the width of the pitch change
in the attack period of VCO 1. With the knob set to
(click stop position), the pitch remains unchanged.
The further towards "minus" it is turned, the lower
the initial pitch becomes; the further towards "plus1 '
the knob is turned, the higher the initial pitch
becomes.
®VCO 2DEPTH
This knob adjusts the width of the pitch change
in the attack period of VCO 2. The function is the
same as that of VCO 1DEPTH©.
©
-KEY ON
—TIME —
\
/
-KEY OFF
The product voltage of
GLIDE and key volt-
/ages.
CONSTANT INTERVALS
i-
VCO OUTPUT
Intervals by the previous key.

FUNCTIONS VCO
The VCO 1and VCO 2blocks consist ofoscillators producing the sawtooth waves correspond-
ing to the pitch of the keys (CONTROL VOLT) from the keyboard and of the Wave Shape Converter
(WSCJ to convert sawtooth waves into square or triangle waves.
(D® FEET
The keyboard covers three octaves with 37 keys.
By making use of the FEET switches, the sound range
to be covered can be shifted as shown in the diagram
below.
FEET
2FEET
4FEET '
8FEET *~
16FEET '
32 FEET '
64FEET '~*
-i
®©WAVE
These switches select the waveforms of the sound
sources.
A:TRIANGLE WAVE
Though this waveform also has harmonics of
the next odd number like the square wave, soft
sound almost equivalent to sine wave (pure
sound) can be obtained since it is rich in
fundamentals.
K: SAWTOOTH WAVE
This waveform has harmonics of multiple in-
tegrals. Unlike triangle and square waves, it has
richer harmonics, often being used as pseudo
sound source for imitating instruments.
n_: SQUARE WAVE
This waveform has harmonics of the next odd
number, being very like the spectrum of a
musical instrument such as aclarinet, but it is
possible to change the harmonic structure by
the PW and PWM knobs and thus this wave-
form is suitable as asound source to produce
sounds peculiar to the synthesizer.
®®LFOMOD
This block modulates the VCO's oscillating fre-
quency by means of aLFO. If this knob is turned
towards 10, the modulation will become deeper.
©®PW
This knob changes the pulse width of the square
wave (50% to 90%). Changing the pulse width
® © ®
changes the harmonic structure of the square wave
and allows it to be used as asound source different
from one produced by asymmetrical square wave.
PW =^X10
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Harmonic components
when PW is changed.
rrvftnr
Frequency (F)
<Q> ®PWM
This knob changes the pulse width of the square
wave at cycles equivalent to the setting of the LFO's
SPEED knob.
PWM: Pulse width modulation
jururu
© © <3
It changes in the order of
LFO: Sine wave
©

functions MIXER/EXTERNAL
The MIXER block regulates the input level to the VCF block. The sound sources to be selected
by the MIXERS can be different for system land system II.
MIXER 1(Input of system I)
System Ican use the VCO 1output and noise or ex-
ternal signals as asound source. VCO Ican be adjusted
in pitch by the TUNE knob alone, therefore it is suited
to the produce basic sound or to create effect sounds by
noise.
®EXT/NOISE
This knob adjusts the input level to the VCF 1
block when external signals or noise connected to the
EXTERNAL IN terminal on the rear panel are used
as asound source.
Selection of external signals or noise can be made
by the EXT/NOISE selector switch in the EXTER-
NAL block.
•The input level of the external signals is deter-
mined by this knob regardless of the TRIGGER
LEVEL knob of the EXTERNAL block.
®VCO 1
Adjusts input level to the VCF 1block when VCO
1output is used as asound source of system I.
MIXER 2(Input of system II)
This can choose VCO 1and VCO 2outputs as
sound sources. The particularity of the VCO 2
SSESS
output is that it is possible to produce, with the help
of the DETUNE knob (5) ,apitch difference to VCO
1. Thus, system II is suited for DETUNE applications.
•For full use of the two systems synthesizer
CS-15see page 20.
®VCO 1
Adjusts the input to the VCF 2block when VCO 1
output is used as asound source.
®VCO 2
Adjusts the input to the VCF 2block when VCO 2
output is used as asound source.
The EXTERNAL block is an input controlling section which permits the use of external signals,
such as from an electric guitar connected to the EXTERNAL terminal on the rear panel, as sound sources
to be passed on to the VCF and VCA.
•For the EXTERNAL signals and TRIGGER LEVEL knob refer to page 15.
NOISE
If the EXT/NOISE switch is set to NOISE, noise can
be used as the sound source with the EXT/NOISE knob
of the MIXER block. The noise is white noise including
all frequency components from low to high frequencies.
It is well suited as sound source to imitate such natural
sounds as wind, waves, and locomotion sounds, etc.
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FUNCTIONS VCF
The VCF blocks change the harmonic structure of the sound sources and control the tone
coloration via the cut-off frequency of the filter, influenced by the control voltages from the envelope
generators, etc.
•When checking the functions of VCF or making tone adjustments, the control of the
BRILLIANCE block should be set to the center.
E> @HPF/BPF/LPF Filter selectors
These switches select the types of filter.
HPF :High-Pass Filter
Frequencies lying between the cut-off fre-
quencies pass. The CUT-OFF FREQ knob is
used to set the width of the band being
passed. In the Lposition we get anarrow
band width, as the FREQ knob is moved
toward Hthe band of frequencies is widen.
Band-Pass Filter
Frequencies lying between the cut-off fre-
quencies pass.
Low-Pass Filter
Frequencies lower than the cut-off frequen-
cy pass. This type of filter is generally used
in synthesizers.
BPF
LPF
Kinds of filters
HPF BPF LPF
/-Pass -Pass -*'
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)® CUT OFF FREQ
This knob controls the boundary frequency be-
tween the range being passed by the filter and the
range being cut, called cut-off frequency. The further
towards Hside it is turned, the higher the cut-off
frequency becomes. This part is very important in
producing basic tone qualities from asynthesizer.
Cutoff Frequency
LPF
>=>
-^harmonics
Pass* -- fc -Cut
F: fundamental fc; Cutoff Frequency
•The cut-off frequency can be also controlled
by the control in the BRILLIANCE block.
•If the cut-off frequency is set so low that all
the harmonics as well as the fundamental are
cut, no sound is produced. This condition exists
when the CUT OFF FREQ knob is turned fully
to Lwith the filter selector set to LPF.
\> ®RESONANCE
If the RESONANCE knobs are turned towards H,
the harmonics in the neighborhood of the cut-off
frequency are emphasized to make tones more ac-
centuated.
Resonance This portion
emphasized.
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FUNCTIONS VCF/VCA
a® LFOMOD
The cut-off frequency can be modulated by the
LFO. The further towards 10 the knob is turned, the
deeper the modulation becomes.
)®EG DEPTH
Adjust the depth of the envelope set by the EG
block to be applied to the VCF.
•If the CUT OFF FREQ knob is used to control
the tone quality with EG DEPTH in position,
and the EG DEPTH is then deepened, some-
times sound will cease to be produced. This
will happen when the cut-off frequency, as
lowered by EG, becomes so low as to cut even
the fundamentals of the sound sources.
)® EG
These switches select the envelope generators of
EG 1or EG 2.
The ordinary envelope wave ys. is produced in
EG 1+and EG 2+, while in EG 1-and EG 2-the
reversed envelope wave v-r is obtained.
The +direction of EG reacts to the direction in
which the cut-off frequency becomes higher.
The VCA blocks are voltage controlled amplifiers which amplify the signals according to en-
velope curves to change the volume produced by VCF.
»<g> INITIAL LEVEL
Adjusts the level (initial level) of the output vol-
ume from the VCA when keys are not depressed. This
is used when effect sounds are to be produced regard-
less of the keyboard or sounds are needed for check-
ing purposes while making adjustments.
•The output volume from the VCA is combined
from the levels set by the INITIAL LEVEL
knob and the EG knob.
D@ LFOMOD
Modulate the VCA at acycle set by the LFO block
and changes volume periodically. The further towards
10 the knobs are turned, the deeper is the modula-
tion.
)® EG DEPTH
Adjust the depth of the envelope set by the EG
block to be applied to the VCA.
&@EG
Select either EG 1or EG 2.
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Initial level
Output level when no
keys are depressed. r-
Total Output Level
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1
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Initial Level
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Trigger signal.
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©

FUNCTIONS EG
The EG blocks create an envelope curve in the four modes of generation of sounds A
(A TTACK), D(DECA Y), S(SUSTAIN) and R(RELEASE) and submit the sound to temporal change. The
EGs (envelope generator) function on the VCF and VCA blocks and produce the envelope curves to lend
temporal change to the tone produced in the VCF blocks and the volume. EGs start in the VCA blocks.
The EGs are controlled by trigger signals from the keyboard, corresponding to the KEY-ON, KEY-OFF
timing, or by external signals.
®EXT/KB D
This switch selects whether the envelopes of EG 1
are triggered by the ON/OFF of the keyboard or by
external signals. For normal keyboard performance
it is turned to the KBD position; to trigger the
envelopes with external signals it is turned to the
EXT position.
®m A(ATTACK TIME)
Adjust the time from the moment when keys are
depressed until maximum change. It controls the
attack characteristics at the beginning of sound pro-
duction. Sliding the control towards Lcauses slower
attack.
@® D(DECAY TIME)
Adjust the decay time from the maximum change
until the stable condition set with the SUSTAIN
LEVEL controls @(5J) is reached. Sliding towards
Lcauses slower decay.
®dD S(SUSTAIN LEVEL)
Adjusts the stable sound level that will sustain
until keys are released after changes by ATTACK and
DECAY TIME have been completed. Sliding towards
10 causes the SUSTAIN LEVEL to become higher.
@® R(RELEASE TIME)
Adjust the time from the release of keys until the
sound completely fades away. Sliding towards L
causes the time to become longer.
@© NORMAL/TIME X5
If the switch is set to the TIME X5position, the
time set with A, D, and Rcontrols will become
approximately five times longer.
©@ @©@>©
Envelope curve
Four states of
the envelope.
SUSTAIN LEVEL
ATTACK TIME
Trigger Signal
DECAY TIME RELEASE TIME
KEY ON KfY Of !
When EG applied to VCF
LPF-
\(T) \The cutoff frequency is
\-
\changed by EG to give
i^> V^.tone changes in time.
\\
fc 1fcs f03 The wave form also
changes.
©

functions LFO/EFFECT
The LFO block modulates each of the VCO, VCF, and VCA blocks and is alow-frequency
oscillating block to induce periodical variations in pitch, tone, and volume.
)SPEED
This knob adjusts modulation speed. The more the
knob is turned towards F, the faster the speed
becomes. Adjustable range is 0.1 to 100 Hz. Change
of speed permits different sound effects.
DFUNCTION
This switch serves to select the waves modulating
each block. The LFO effect depends greatly upon
the LFO waveform. Confirm its effect by ear.
%:Sine Wave
Agently changing effect is obtained. It can
give avibrato effect to the VCO, growl
effect to the VCF, and tremolo effect to
the VCA.
f\ :Sawtooth Wave
Intermittent sudden and slow changes.
S/H :Sample and Hold
Causes irregular changes. S/H samples an
instant value of the irregularly changing
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noise waves, and sustains that value until
another sampling is made, thus producing
irregularly changing modulation signals.
The sampling period is determined by the
SPEED knob.
The EFFECT block controls pitch and tone quality temporarily during performance and
permits variations in performance.
@PORTAMENTO
Portamento is an effect by which the sound of
one key smoothly changes into the pitch of the next
one depressed. This control adjusts its shifting speed.
The further it is raised towards L, the longer the
transition time becomes.
BRILLIANCE
An effect cojitrol to be used to change tonal
quality, previously set by the VCF block on the
panel, during playing.
®VCF Selector Switch
Selects the VCF on which the BRILLIANCE
effect is functioning.
If the switch is set to 1, it actuates VCF 1, if it is
set to 1+2, it actuates both VCF 1and 2; if the
switch is set to 2, it actuates VCF 2.
©

functions EFFECT/EXTERNAL
)BRILLIANCE CONTROL
When the control is set to the center ,the
tone quality is that set by the panel; when set to +
side, the cut-off frequency becomes higher, which
will generate bright tones including higher harmonics,
while set to -side, the cut-off frequency becomes
lower, which will generate soft tones.
•Depending on the kinds of filters, the position
set by the CUT OFF FREQ knob, and other
factors, if the control is slided, no sound will
be produced in some cases.
PITCH BEND
Amanually operated control used to change the
pitch during playing.
©LIMITER
Determines the variable pitch range of the pitch
bend control. Position of the LIMITER switch
brings about the following:
N(NARROW) ±200 Cent.
M(MIDDLE) ±300 Cent.
W(WIDE) ±1,200 Cent. (±1 Octave)
®PITCH BEND LEVER
If the lever is set to +side, the pitch becomes
high; if set to —side, it drops.
The synthesizer effect can be applied to external signals by connecting external sources such
as amicrophone or electric guitar to the EXTERNAL IN terminals on the rear panel.
OEXTERNAL IN
Terminal to input external signals.
O0/-20 Input Sensitivity Selector Switch
Set this switch according to the external signal
levels. In the case of low level inputs such as micro-
phone the switch is set to -20 (dB) and in the case
of electric guitar, electronic piano, and mixer out-
puts, to 0, respectively.
©TRIGGER LEVEL
EG 1can be triggered by external signals. (For
EG 2this is not possible.) The TRIGGER LEVEL
knob is to be set so that TRIGGER ON/OFF signals
can be generated at aproper level from external sig-
nals, with the trigger selector (43) of the EG 1block
set to EXT.
•When trigger signals are supplied by external
signals, the position of the EXT/NOISE switch
@and EXT/NOISE knob (19) of the MIXER
1block are irrelevant.
«* .0.
6
0
•The TRIGGER LEVEL knob @is irrelevant
in the adjustment of the input levels of the
external signals.
•External signals can be used as the sound source
alone without any trigger function. (In this
case, the EXT/KBD switch @> is set to KBD.)
)EXT/NOISE
When external signals are used as the sound source,
the switch is set to EXT. When noise is used as the
sound source, it is set to NOISE.
©

CONNECTING TWO SYNTHESIZERS
The CS-15 has terminals for input and output of CONTROL VOLT signals to control the
voltage corresponding to the interval of the keyboard, TRIGGER to EG. It can also feed them to adif-
ferent synthesizer having the same input/output terminals or receive them from another synthesizer.
Thus, one keyboard can control many VCO -VCF -+ VCA.
•The terminals of the following models have equivalent function as the CONTROL VOLT
of the CS-15. CS-10, CS-30 and CS-30L: KEY VOLT
CS-30: CONTROL VOLT of the SEQUENCER OUT port
•CONTROL VOLT and TRIGGER can
be fed in and out independently.
•For further details on main and sub con-
trols when two or more synthesizers are
connected, see the BLOCK DIAGRAM
on page 22.
€> CONTROL VOLT
An input/output terminal for the CONTROL
VOLT or KEY VOLT terminals of other synthesizers.
IN VC0 1/VC0 2
Terminals to feed the CONTROL VOLT or KEY
VOLT of other synthesizers into VCO 1or VCO 2.
OUT
Aterminal to feed it to other synthesizers.
OTRIGGER
Input/output terminals between TRIGGER termi-
nals of other synthesizers.
IN EG 1/EG2
Terminals to feed in TRIGGER signals controlling
EG 1or EG 2from other synthesizers.
OUT
Aterminal to feed TRIGGER signals to other
synthesizers.
•Wrong connection of these controls can cause
damage, so careful attention should be paid
when making connections.
The following is an example in which the CON-
TROL VOLT and the TRIGGER signals of the
synthesizer 1(CS-15) are transferred to the VCO
2of the synthesizer 2(CS-15). Thus the synthe-
sizer 1keyboard can control three systems con-
sisting of two systems of the synthesizer 1and one
system (VCO 2) of the synthesizer 2at the same
time. The VCO 1side of the synthesizer can be
normally operated by the keyboard of the synthe-
sizer 2. As aresult, amulti-keyboard use is
possible, in that the synthesizer 1controls three
systems and the synthesizer 2one system.
SYNTHESIZER 1
-CONTROL VOLT
-IN 1OUT
TRIGGER-
©

applications IMPORTANT POINTS
1. HOW TO SELECT WAVEFORMS
Waveforms have to be considered first of all when
creating tones. The CS-15 provides three kinds of
waves, A(triangle), [\ (sawtooth), and f~L(square),
as well as noise. Let us explain the particular use of
each.
The most fundamental is the N. (sawtooth wave),
which has atonal quality (harmonic components)
-0 M
LFO MOD ''" PW
Spectrum of triangle wave
OdH
-10
-?0
30
d0
-50
-60
Frequency (F)
Amplitude (A)
Amplitude
Period -
Time
3F 5F 7F 9F 11F
AAAA A
925 49 81 121
Spectrum of sawtooth wave
OdB
-10
-20
-30
---Time
Period
Frequency (F) 2f 3F 4F5F6F iof
Amplitude (A)| 4 $ ii~-$>
Spectrum of symmetrical
square wave Period
OclLi
-10
?Q
Frequency (F)
Amplitude (A)
Amplitudef
ri_h--Time
3F
A
3
5F
A
5
7F 9F IIF
AAA
79II
similar to those of trumpet and violin. As one can
change tones with pulse width (PW), this wave has a
variety of uses. For example, if PW is 50%, its tone
resembles that of the clarinet. If PW is 60 to 70%,
the tone resembles that of asaxophone. If PW is 80
to 90%, the tones resemble those of an oboe and
bassoon. The pulse waves are suitable for creasing the
tones of reed instruments. Though the triangle wave
has harmonic components similar to that of a50%
pulse wave, it sounds soft because of their low level.
2. HOW TO SELECT THE FILTER
The function of the filter is to cut the harmonics
of the sound source waveforms to approximate them
to the desired tones. The filter of CS-15 provides a
selection of three modes, HPF (high-pass filter),
BPF (band-pass filter), and LPF (low-pass filter).
Qfc=i
lfo mo EG DEPTH
The HPF removes harmonics lower than the cut-
off frequency but leaves high harmonics. The BPF
removes high and low harmonics but leaves harmonics
within the range of the cut-off frequencies. The LPF
removes high harmonics but leaves harmonics lower
than the cut-off frequency. When producing instru-
ment sounds, the LPF is used in most cases. The
reason for this is that the LPF can control high har-
monics components while retaining the fundamentals.
When lighter tones are desired or low components
are to be cut, the BPF is used. The HPF is used when
tones like those of cymbals are made or effect sounds
are produced.
Let us explain general procedures of operations
while taking the example of producing trumpet
sounds.
©

applications HOW TO CREATE THE TRUMPET SOUND
VCO 1Setting
Set waveform to |\ .FEET selecting range to
16'. Set LFO MOD knob fully to 0. Usually the LFO
controls are used for finishing touches after the basic
sounds have been made with VCF and VCA.
The positions of the PW and PWM switches do not
matter. These are used only when [~L_ is selected as
waveform.
MIXER 1Setting
Sends the signals selected in VCO 1to VCF.
Other knobs including the MIXER 2must be all fully
turned down.
HI 50 'N9D
LFO MOD '"" PW
VCF 1Setting
Set the filter mode to LPF. Set the CUT OFF
FREQ knob fully to H. This is to feed the whole
spectrum of the Nwaves including the highest har-
monics to the VCA. With the RESONANCE and LFO
knobs turned fully left, set the EG selector switch to
EG 1+. EG DEPTH is set to 0.
VCA 1Setting
With EG selector switch set to EG 1, turn the EG
DEPTH to fully right. Set INITIAL LEVEL, LFO
MOD to 0. Thus, EG 1alone determines changes in
volume.
EG 1Setting
With the EXT/KBD switch set to KBD, raise the
SUSTAIN control. Set the NORMAL/TIME X5
switch to NORMAL. This produces an envelope
shaped JL. Set the output volume as required.
©
FIRST STEP -VCF
In this condition, amelody can be played on the
keys. But to produce the tonal quality of the trum-
pet requires another step, operation of the CUT
OFF FREQ knob. While playing the keyboard, turn
the CUT OFF FREQ knob slowly to the left. This will
give you agradually lowering cut-off frequency,
causing the harmonics at ahigh range to be cut off
and tones to become softer. When the knob is at a
position somewhat left from center, you will be able
to obtain sound approximating that of atrumpet.
This adjustment is to be continued until roughly satis-
factory results are obtained.
Note: Is the BRILLIANCE control on the left of
the keyboard set as shown below? Operate
this control too. With the switch set to VCO
1, if the control is moved up and down, the
tones become hard or soft like the effect of
the CUT OFF FREQ knob.
•S
LFO MOD EG DEPTH
SECOND STEP -EG
The sound has been made to resemble that of the
trumpet with help of the VCF, but it still has no ex-
pression. This is because the EG 1so far was used
only to raise the SUSTAIN LEVEL. It is necessary to
study the EG 1setting more in detail to come still
closer to the characteristics of the trumpet. As the
trumpet is not an electronic instrument, it does not
produce acertain, constant volume and sound every
time it is played. The characteristics of the instru-
ment are displayed on the attack of the sound.
Though this is only instantaneous, something like the
sound of amusical instrument cannot be generated
without its reproduction. The sound of the trumpet
^

depends upon the lip vibration of the player, so that
the sound is small in volume and soft in tone at the
outset. As soon as lip vibration starts, volume and
tone reach apeak and settle then to astable level
EG and Filter
Let us consider the difference between peak and
stable level. In the case of the trumpet, this difference
presumably is not so big. So we decrease the SUS-
TAIN level only by that amount.
When the SUSTAIN level has been determined,
begin applying EG on the VCE. Raise the EG
DEPTH knob of VCF 1. When the keys are depressed,
clicks are heard at the beginning and the tones change
while the keys are kept depressed. Now readjust the
CUT OFF FREQ knob under the assumption that the
continued depressing of the keys represents the
trumpet being continuously blown.
Set DECAY TIME to a proper value with D. (As
there is only aslight difference between the peak
level and the SUSTAIN level, only asmall effect is
necessary.)
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Determine the ATTACK TIME with Awhile de-
pressing the keys. This is very delicate and must be
done with care. Aslight sliding will be sufficient.
Now, as the EG DEPTH has been raised to 10, the
tone change at the envelope peak seems to be too big.
Therefore turn the EG DEPTH down to about the
center position. Thus you will find that the tone
change in the moment of attack approximates that of
the trumpet. But this results in achange in tone at
the SUSTAIN level. Adjust this again with the CUT
OFF FREQ knob. This means that the depth of EG
being applied to VCA and rate of the depth applied
to VCF have been controlled by the EG DEPTH
of the VCF.
Raise the RELEASE TIME only slightly so that
the sounds do not fade away suddenly at the end.
This completes the trumpet sound creation. If
slight RESONANCE is added, it makes the tones
clearer. Has the final setting been made as illustrated
below?
Try to create the sounds you desire little by little
by repeating operations such as described above many
times in various ways. Then try to produce sounds
other than those of the trumpet. If you continue to
generate various sounds, you will come to under-
stand the functions of the synthesizer.
Final Setting
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applications USE OF TWO SYSTEMS
1. Using them with the same tone quality
a. Pitch (FEET) set at same position for unison ef-
fect. Though slightly electrical, it is possible to
produce arich sound.
b. Even if the pitch setting is the same, aim at abeat
effect by changing the pitch of VCO 1and VCO 2
slightly.
c. Produce unique sounds with the FEET of VCO 2
set to 1to 2octaves up or down of VCO 1
.
d. Produce sounds that are special to the synthesizer
by making VCO 2perfect fifth interval of VCO 1
by means of DETUNE of VCO 2.
2. Using them with different tone quality
a. It is possible to change the tone quality instantane-
ously by setting two kinds of tones and employing
the MIXER part during performance.
b. Effects that could not be produced with one VCF
and EG system are possible by the double layout.
Performing FEET changeover with both systems set
to the same tone quality.
Set VCO 2and EG 2to the tone of the trumpet by
referring to the previous page. Balance VCO 1and
VCO 2for unison with the use of VCO 2's DETUNE
knob. Complete unison can be obtained when there
is no beating between the two VCO's after the knob
is adjusted. Though the sounds produced may be
slightly electrical as compared with those in only one
system, aricher sound can be obtained.
Beating
Perfect Fifth
Unison
Perfect Fifth
Next, slide the pitch of VCO 2with DETUNE.
Beating will arise between the two VCO's, which
shows you that the sound source stems from two sys-
tems. This is useful in obtaining aconcert effect and
producing accordion sounds.
Return the DETUNE to unison and produce
various sounds with FEET changeover. Return VCO 1
FEET to 8' and VCO 2to 4' to try synchronizing
VCO 1and VCO 2with VCO 2in the, one octave up
position.
/^5jP\ ^-. i^n_
VOLTAGE
CONTROLLED
OSCILLATOR
2
LFO MOO 'PW
With the settings above you will notice that the
sound clarity is enhanced. If the sound of 2octaves
higher is added, an effect just like supporting
the melody with apiccolo is obtained. Let us now
set VCO 2to a lower octave. Set FEET to 32'. This
produces strong tones. Then set it to 64'. You can
achieve heavy bass sounds that even an electric bass
would be hard put to surpass.
Using two systems set to different tone qualities
It is difficult to change the tone of the synthesizer
during performances. When two systems are in use
like CS-15, this makes it very convenient to change
the tones by operating the MIXER with different
tones having been set previously (for example,
trumpet in 1and flute in 2) set. To use the trumpet
tones turn the VCO 1knob to right. To use the flute
alone turn it to left and turn VCO 2to right. It is
also possible to use both of them by balancing the
tones with VCO 1and VCO 2.
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