Ring Modulation; Pulse Width Modulation - EML SynKey Owner's Manual

4. The dotted shapes .•'•. and \\ signify
sampled /I and m\ shapes. Instead of
smoothly varying, these voltages are broken
into steps. As you change the SPEED control
you will find that you can generate various
pitch patterns for special effects.
Experiment with various combinations of
MOD. OSC, SHAPE, and SPEED controls to
become thoroughly familiar with them.
B. AMPLIFIER ENVELOPE - The AMPLI
FIER ENVELOPE generates a voltage at each
key depression. This voltage is applied to the
VOLTAGE CONTROLLED AMPLIFIER. The
VOLTAGE CONTROLLED AMPLIFIER'
determines how the loudness of your SynKey
changes with time after you depress a key.
There are three controls in the AMPLIFIER
ENVELOPE: ATTACK, DECAY, and
SUSTAIN. Note: no new envelope can be
initiated unless all keys have been released.
1. The ATTACK control will determine how
long it takes a sound to reach maximum
loudness. Clockwise rotation results in longer
attacks. Once the maximum loudness is
reached the process is reversed and the
sound level begins to decrease. The time to
reach silence is determined by the DECAY
control. With the SUSTAIN control off (set
to 1), the envelope will always be the same
regardless of when (or whether) you release
the key. Experiment with various combinations
of the ATTACK and DECAY controls. You
should be able to make loudness versus time
varions such as the following:
Don't be surprised that you can't hear how
the loudness is changing at short attack and
decay times — the time can be as short as
2/100pthof 3 second.
2. V^tj^he SUStAIN control at other than 1
the situaiion is a little different. The envelope
(andrloudness) will attack to the maximum
level and then begin to decay. If a key is not
held down, the envelope will decay to zero
level as before. If a key is being held down,
however, the loudness will decay to the level
set by the SUSTAIN control and remain there
as long as the key is depressed. Upon key
release, the loudness will decay toward
silence at aTSte determined by the DECAY
control. Holding a key down simply prevents
the loudness from decreasing below the level
set by the SUSTAIN control.
By experimenting with all three controls
you should be able to make sounds change
loudness with time as shown below.
KEY RELEASE
If you read our discussion of musical
instruments and are starting to think in terms
of pitch, loudness, and timbre, you may have
guessed that to play plucked or struck
sounds you will use fast attacks, medium
decays and no sustain. Horn sounds will
require medium short attacks and decays
with moderate to high sustain. An organ-like
sound will have fast attack and decay with
maximum sustain.
C. FILTER ENVELOPE - The FILTER
ENVELOPE has the same controls and
works in the same way as the AMPLIFIER
ENVELOPE. It is, however, applied to the
VOLTAGE CONTROLLED FILTER. More
about that in Section III.
D. VOLUME CONTROL - The VOLUME
CONTROL is grouped with the controllers as
a matter of convenience. It simply sets the
overall volume of the SynKey. Generally
speaking, the best signal-to-noise ratio is
obtained with the SynKey VOLUME turned
well up and your amp volume down. You will
find that some compromise is required to
accommodate different kinds of sounds. At a
gig, the best bet is to set your amp for the
proper level with the SynKey volume at 7
while playing your "thinnest" sounds, then
you will be able to turn down the SynKey
volume for songs with thicker sounds.
Now is a good time to practice what you
have learned so far and let it sink in. Try
combining different envelopes, root wave
forms, chord structures, and varying degrees
of portamento and vibrato.
III. MODIFIERS: There are three modifiers
on the SynKey. Basically they pertain to
timbre modification. They are:
A. Voltage Controlled Filter
B. Ring Modulator (designated by RING)
C. Pulse Width Modulation
A. VOLTAGE CONTROLLED FILTER - The
filter is primarily responsible for the wide
variety of timbres available on your SynKey.
It accomplishes this by emphasizing or
de-emphasizing different overtones or har
monics naturally present in the basic pitch
waveforms.
1. Begin by setting your SynKey's controls
as shown in Figure 4. With resonance set to 1
and mode set to LP (low pass), gradually
rotate the TUNE control clockwise while hold
ing down a low key. Notice that the note
becomes progressively brighter. As you
rotate the TUNE clockwise, you are actually
permitting more overtones to pass (remember
overtones are integral multiples of the basic
pitch) without changing the strength of the
fundamental pitch.
2. Now rotate the MODE control to BP (band
pass) and again rotate the TUNE control.
(You can play a little riff now and then too —
it helps make subtle timbre changes more
evident.) Now as you rotate clockwise, you
will tend to pass a band of overtones. When
fully clockwise the fundamental and lower
overtones will tend to be reduced — resulting
in a still brighter timbre.
VOLTAGE CONTROLLED OSCILLATOR
ml 1 mi ]
OSCILLATOR CONTRCX
MODULATION OSCILLATOR
VOLTAGE CONTROLLED FILTER
IUNE ttiONANCf MODI
FILTER ENVELOPE
MCAV SUSTAIN
VOLTAGE CONTROLLED AMPLIFIER
AMPllflfft ENVELOPE
Fig. 3 Controllers
OSCILLATOR CONTROL MODULATION OSCILLATOR
VOLTAGE CONTROLLED FILTER
/ •■/ •-/
•I SON a NO wOOt
fllTER ENVELOPE
} *• 6 2 W 6 J
VOLTAGE CONTROLLED AMPLIFIER
Fig. 4