Oscillator
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The prime driver of the 3A's
sound is the unique* additive synthesis section in the oscillator: five
different partials, with the usual waveshapes and each an octave apart,
can be mixed to create many different tones. The sound can be
thickened using the 8' chorus, which provides a kind of pulse-width
modulation effect on square waves: turning the knob right increases the
rate and depth of the effect. The 3A's sound can be characterized as
one where even harmonics (2,
4, 6, 8, etc) usually dominate over odd
harmonics (3, 5, 7, etc.).
The Ricko-3A builds on this basic structure, providing individual
envelope** and pulse-width controls on each partial and a general phase
control:
adjusting the phase control changes the phase relationship between each
partial, allowing harmonics to cancel or boost.
You can further subtly adjust the tone to emulate many early analog
synthesizer models by browsing though the waveshape variations using
the variation button: this varies all the waveforms, but with little
effect on the square waves by their nature. The setting Soft causes a sawtooth wave to be
convex upward. The setting Hard causes
a sawtooth wave to be concave upwards. The setting Pointy causes a sawtooth wave to
be slightly S-shaped. The setting Half
causes a sawtooth wave to have a gap, such as shown on the
panel.
A bonus feature is the Scream
control: usually this should be turned fully left (off). Turning this
control right causes the 16', 8' and 4' partials to rise in frequency:
at hard right they are in tune with the 2' partial. The partials are
synchonized to the 32' partial, and can produce sounds rather like
frequency shifting, ring modulation or hard syncing, depending on the
mix.
* Unique to Roland. The SH-7 also had a version of this;
apparantly
the preset synths SH-1000 and SH-2000 had similar circuits under the
hood.
** Tip: Because it is easy to miss the 0 position (12:00 o'clock) for
the EG SENS +/- controls,
which let you
have dynamic control of the levels of each partial, when you don't want
any sound for that partial, turn the control to 11:55 rather than 12:00.
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Dynamics
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The 3A allows different
envelopes for the low-pass filter cutoff frequency and for amplitude
using conventional ADSR generators. The EG Sens control adjust the
modulation of the cutoff frequency. The Resonance control adjusts the
filter resonance: at its higher settings it will self-resonate.
The Ricko-3A also provides controls to adjust filter strength (hard
left has a slope of 15 db/8ve, hard right has a slope of 24 db/8ve) and
keyboard tracking. MIDI velocity may be used to adjust the amplitude. A
simple Pan control is
provided.
The Performance section
controls basic tuning, portamento (sliding between notes) and octave
selection. The Mono
button allows selection between four-voice polyphony (Off) and
low-note-priority, no retriggering monophonic operation. (You can use
the four-note polyphony to recreate the voicing behaviour of Roland's
Jupiter 4.) Please note that the Ricko-3A has been primarily designed
to
perform acceptably in monophonic operation; dense polyphony may
have relatively high CPU usage, depending on the patch.
The Root section
selects the root key
you are playing; the Ricko-3A does not use equal temperament but uses a
kind of well-tempered scale; the effect will not be noticed on sounds
with chorus and vibrato, but helps pipe organ sounds.
It can also help simulate the tuning variations that characterize many
analog synths: these could be caused by circuits heating up, by
drift caused by noisy circuits, by portamento, by inexact component
in the resistor chain of the keyboard, or just because pitch control
was not spring loaded.
The Clock button, when on,
retriggers the envelope from the MIDI clock, as divided by the middle
button in the Sampler section.
The virtual LED above the level control will give some indication that
the signal is too high and needs adjustment down. This can particularly
be caused by the flanger. The button above the virtual LED allows
slightly different envelope characteristics.
(The on/off graphic is just for fun.)
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Modulation
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The Low Frequency Oscillator
(LFO) can be used to control Vibrato, Growl (cutoff modulation),
Tremelo (amplitude modulation) and Swirl (panning). The usual waveforms
can be selected.
The Delay slider inserts a
delay from when a key is pressed (gated) until when the LFO signal
reaches full strength. This contributes to the singing quality of many 3A patches.
The LFO can run free, typically the case for Vibrato, but it can also
be synchronized to the start of the MIDI transport or to the MIDI bar
start signal. The setting Clock
resynchonizes on the MIDI clock, at the division set by the middle
button in the Sampler section.
The Sampler is a Sample and
Hold unit connected to the Oscillator pitch. At intervals based
on dividing the incoming MIDI clock signal, the value of its own LFO is
sampled and held until the next clock. This allows various kinds of
glossando and semi-random sounds. The Level slider controls the amount:
keep this fully down if you don't want any Sample and Hold
effect. The LFO can be run free, or be gated to the start of the
MIDI transport or to the MIDI bar start signal.
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Flanger
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The flanger section has an LFO
section at the top, with rate, modulation level, waveshape and
synchronization controls. The Flange
Strength control in the centre of the panel controls the effect:
turn it hard left when you want no effect.
The centre frequency and resonance of the flange effect are set by the
controls at the bottom of the panel.
The Ricko-3A can be used to
re-create
many of the sounds of the 1970s Roland® SH synthesizers. Its MIDI
automation and sync
features allow use in modern VSTi
hosts.
Its
emulation features can also reproduce aspects of other
discrete-component
analog micro-synths. (In the 80s, there was a dramatic homogenization
of
sound as manufacturers adopted the same chips: for example, the same
oscillator chip was used in Roland's Jupiter 6, Moog's MemoryMoog,
Oberheim's
OBXa, OB8 and OB-SX, Steiner and SC's Prophet 5, T8, Pro One and 600.
Similarly, the same
filter chip could be found in synths by Fairlight, Crumar, Elka,
Oberheim, PPG,
PAIA, Doepfer, and Sequential Circuits. Another filter chip was used by
Kawai, Korg, Cat,
Siel, E-mu and others. Even more than adopting the same chips, 80s
manufacturers
adopted basically the same architecture and left innovation to Yamaha,
Kurzweil,
PPG and the sampler-makers. Now thanks to virtual synthesizers and
programs
such as SynthEdit, we are in a position to create synths with
individual character
again.)
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