ALYJAMESLAB SY-4X ► Virtual Syncussion SY-1 extended

The Legendary Pearl Syncussion SY-1

Syncussion SY-1

A Technical Overview of the Original

The Pearl Syncussion SY-1, introduced in the late 1970s, is a legendary drum synthesizer known for its unique sound shaping capabilities and wide tuning range. At the core you find two identical modules each containing two oscillators, a custom filter, two envelope generators, LFO and Sample & Hold, it also got a noise generator. It has been the secret weapon of many. Below are the key technical aspects of this iconic machine:

Oscillator Modes

The SY-1 features six oscillator modes: they are like internal preset connections: single oscillator, FM, dual oscillator mix, dynamic oscillator mix, FM/Custom Ramp OSC*, and pure noise. These modes provide a wide range of sound possibilities, from deep bass kicks to high-pitched toms and complex noise effects.

note: My SY-4X Features additional G and H Modes and options to further use the Noise generator. Every preset modes have some internal tuning and connections adjustments.

Voltage Controlled Oscillator (VCO)

The SY-1 features a voltage-controlled oscillator utilizing a TRI core and CMOS 4069 hex inverters. This configuration allows for complex waveform generation through cross-modulation, providing rich and diverse sound textures. The cross-modulation capabilities and extra harmonics inherent from the VCO circuit contribute to the SY-1’s signature sound.

Voltage Controlled Filter (VCF)

The VCF in the SY-1 is a state-variable filter using 4069 inverters. It stands out due to its unique characteristics (poles spreading), resulting from unequal integrator capacitors and the absence of direct resonance control, offering distinctive filter sweeps and tones.

note: Filter response PLOT from SY-4X -increased resonance to better see the 2 poles moving differently.

Voltage Controlled Amplifier (VCA)

The VCA utilizes a standard transistor pair-diff opamp setup, ensuring reliable amplification and sound clarity. This configuration contributes to the SY-1's powerful and punchy audio output.

Modulation Capabilities

The SY-1 is equipped with an LFO with square and triangle waveforms for vibrato or audio rate modulation effects, and a sample and hold circuit for random pitch changes with each hit (lovely). The envelope generators EG1 (called SWEEP -trigger independent) and EG2(dynamic -from trigger pulse) offer extensive control, allowing intricate sound shaping.

Pitch and Decay Controls

The module includes tune, decay, and filter cutoff (WIDTH) controls the latter actually controlling the amount of VCF modulation, enabling users to fine-tune the percussive sounds. The pitch sweep feature, with speed, range, and up/down controls, allows for dramatic pitch dives and rises. A notable detail -the decay is not only affected by the decay slider but also by the tune slider.

Legacy

The original SY-1 was used by artists such as Prince, Kraftwerk, Herbie Hancock, Aphex Twin etc. contributing to its legendary status.

The Pearl Syncussion SY-1 remains a highly sought-after percussion synthesizer for its distinctive analog sound and versatile features. The SY-1 offers a unique and dynamic tool for creating a broad spectrum of percussive sounds. I have heard it used by many adventurous and skilled drummers over the internet and as always this baby got the -secret weapon flag.

*note: MODE E is often incorrectly labeled as a mix of FM and noise. In reality, there is no noise generator in this mode. What actually happens is that OSC2's TRI waveform is transformed into a pseudo SAW waveform using a clever technique: alternating pitch modulation. During half of the TRI waveform’s period, the frequency is set super high, then returns to normal during the other half. How crazy is that? The artificially produced SAW waveform is approximately twice as high in frequency.

Get It Now

All manufacturer and product names mentioned on this page are trademarks of their respective owners, which are in no way associated or affiliated with ALYJAMESLAB. The trademarks of other manufacturers are used solely to identify the products of those manufacturers whose tones and sounds were studied during ALYJAMESLAB sound development. All names of instrument and inventors have been included for illustrative and educational purposes only and do not suggest any affiliation or endorsement of SY4X by any company or instrument inventor

Meet SY-4X

SY-4X is not only a perfect re-creation of the SY-1's inner circuit, but it also offers significantly more options. These include four units in one, trigger-controlled 'mode scanning,' CMOS circuit 'defect' control to enhance harmonics beyond the original, real-time VCF integrator cap offset for dynamic pole movement, fine-tuning envelope response to match your playing style, and additional features like Drum Kit and Keyboard Modes.

Syncussion SY-4X

4 Times the fun

SY-4X provides four Syncussion SY-1 modules in one neat package, with some modules featuring additional modifications like noise direct injection or a Custom Mode A (see Modes below). The four modules allow for creating an 8-voice drum kit, four mono synths (coupled voices = 4 oscillators per module), or a four-voice poly synth (4 x 4 oscillators). You can also mix modes, such as three modules in Drum Kit mode and one in mono synth mode (keyboard controlled). In any play mode, you have full control over every voice parameter—sky's the limit!

Syncussion SY-4X VST Plug-In

Trigger to Modes

SY-4X has an option to use a randomly generated mode sequence synced to each new trigger per drum. This bypasses the analog potentiometer and scrolls through the modes following the generated sequence, which is also kept in memory for perfect recall. You can regenerate the sequence at any time. It supports roughly 50Hz modulation—in case you trigger it 50 times per second! :)

CMOS Oscillators ?

Without getting too technical, this type of VCO uses a CMOS inverter chip and a bias circuit to control the oscillation. If it’s not ideal, one half of the resulting waveform might differ slightly from the other, producing a distorted waveform and extra harmonics. A CMOS parameter in SY-4X is available for each of the 8 voices (2 per module), allowing you to control or enhance this 'defect.' The reset value reflects the original hardware response behavior.

Syncussion SY-4 CMOS Inverter Oscillators

An Unusual Filter

SY-4X models the unique filter design of the Syncussion. It is a 2-stage low-pass SVF with a twist: the control voltage has more effect on the second stage, which is set to a higher cutoff by design. This causes the two filter poles to spread apart depending on the control voltage, creating an almost vowel-like effect. Both cutoff points have a ratio of roughly 4:1, and the CV is at a ratio of 2.13:1. The SPREAD parameter allows you to change or modulate the frequency ratio, controlling how far apart the poles are set.

Technically what is happening is that the CV limiting resistor is lower for the second stage (47K vs 100K) resulting in a wider voltage span and the second integrator capacitor is roughly half the value of the first stage (1nF vs 2nF) which cause those 2 stages to be tuned differently (second one is higher). The plot below uses filter feedback to increase resonance which is a mod you could do on the original

Envelope 2 Response Control

Envelope 2 controls the VCA, the filter, and, depending on the selected MODE, the tuning. The envelope generator's triggering pulse levels vary with attack strength, providing adequate accent to the output.
SY-4X has a parameter called HOLD. At its lowest, it mimics the original hardware response, but increasing the value changes the envelope response to something more linear. This can be very useful if you need an almost gated response, or, put another way, more body with an ultra-fast decay.

Default response is the typical capacitor discharging shape—snappy and punchy. But what if you could change that at will with a simple modification, turning the response from exponential to logarithmic? This setting alone can dramatically change the resulting sound, giving you way more mileage out of this synth.

Berserk Mode

An optional mode called BERSERK will turn the whole unit into a nastier beast. Choose between a pre-filter asymmetrical clipping stage or a post-filter crusher stage (roughly 6kHz, variable bit rate). Both Berserk types are tamed by a Stability parameter. This mode can be automated! Use it for subtle crunch or go full Berserk.

Syncussion SY-4X Berserl Mode

Keyboard Modes

The Syncussion could also be controlled from external CV, it could track more or less over 4 octaves and can be used to play actual notes.
SY-4X brings that to another level. By switching a module from Drum Kit mode to Keyboard Mode, you will now control both voices from your keyboard at the same time.

One of the features is that you can optionally switch to near-perfect pitch tracking between oscillators, but not only that: You can now scale the pitch CV to an actual musical pitch following a defined scaling rule of your choice.

The TUNE slider will now be scaled, as will the incoming CV, to either a 1-step scaling (for example: whole tone) or a full scale. This scaling works in both Drum Kit (nice with S&H) and Keyboard Modes. In absolute pitch mode, you define the ROOT of the scale; in relative mode, the current played note will be the root.

There are more than 60 scales to play with including some microtonal ones...remember that you can choose a different scale per module in case you want to impress your Jazz buddy.

Scales List

scaling rules

One Step Scaling

NoScaling: No scaling is applied; the pitch remains unchanged.
Semitone: Scales the pitch to the nearest semitone, which is the smallest interval used in Western music (1/12 of an octave).
WholeTone: Scales the pitch to the nearest whole tone, which is equivalent to two semitones.
QuarterTone: Scales the pitch to the nearest quarter tone, an interval half the size of a semitone, often used in modern classical and non-Western music.
MinorThird: Scales the pitch to the nearest minor third, which is equivalent to three semitones.
MajorThird: Scales the pitch to the nearest major third, which is equivalent to four semitones.
PerfectFourth: Scales the pitch to the nearest perfect fourth, an interval equivalent to five semitones.
PerfectFifth: Scales the pitch to the nearest perfect fifth, an interval equivalent to seven semitones.
MinorSixth: Scales the pitch to the nearest minor sixth, which is equivalent to eight semitones.
MajorSixth: Scales the pitch to the nearest major sixth, which is equivalent to nine semitones.
MinorSeventh: Scales the pitch to the nearest minor seventh, which is equivalent to ten semitones.
Octave: Scales the pitch to the nearest octave, an interval spanning twelve semitones.

Musical Scaling

Major: Scales the pitch to the nearest note in the major scale, characterized by a happy and bright sound.
NaturalMinor: Scales the pitch to the nearest note in the natural minor scale, characterized by a sad and melancholic sound.
HarmonicMinor: Scales the pitch to the nearest note in the harmonic minor scale, which has a distinctive raised seventh degree.
MelodicMinor: Scales the pitch to the nearest note in the melodic minor scale, which ascends with a raised sixth and seventh degree but descends like the natural minor.
PentatonicMajor: Scales the pitch to the nearest note in the major pentatonic scale, a five-note scale common in folk music.
PentatonicMinor: Scales the pitch to the nearest note in the minor pentatonic scale, a five-note scale often used in blues and rock music.
Blues: Scales the pitch to the nearest note in the blues scale, which includes a flat fifth, adding a characteristic "bluesy" sound.
Dorian: Scales the pitch to the nearest note in the Dorian mode, which has a minor third and a major sixth.
Phrygian: Scales the pitch to the nearest note in the Phrygian mode, which has a minor second and a minor third, giving it a Spanish or flamenco feel.
Lydian: Scales the pitch to the nearest note in the Lydian mode, characterized by a raised fourth degree.
Mixolydian: Scales the pitch to the nearest note in the Mixolydian mode, similar to the major scale but with a lowered seventh.
Locrian: Scales the pitch to the nearest note in the Locrian mode, characterized by a diminished fifth.
Chromatic: Scales the pitch to the nearest note in the chromatic scale, which includes all twelve semitones within an octave.
Qawwali: Scales the pitch to the nearest note in the Qawwali scale, used in Sufi devotional music with distinctive intervals.
Jegog: Scales the pitch to the nearest note in the Jegog scale, used in traditional Balinese music, often featuring a unique tuning system.
BebopMajor: Scales the pitch to the nearest note in the Bebop major scale, which includes an added chromatic passing tone.
BebopMinor: Scales the pitch to the nearest note in the Bebop minor scale, which includes an added chromatic passing tone.
HungarianMinor: Scales the pitch to the nearest note in the Hungarian minor scale, characterized by raised fourth and seventh degrees.
Persian: Scales the pitch to the nearest note in the Persian scale, featuring half and three-quarter tone intervals, giving it an exotic sound.
SpanishGypsy: Scales the pitch to the nearest note in the Spanish gypsy scale, also known as the Phrygian dominant scale, with a distinctive sound used in flamenco music.
Hirajoshi: Scales the pitch to the nearest note in the Hirajoshi scale, a Japanese pentatonic scale with unique intervals.
RagaYaman: Scales the pitch to the nearest note in the Raga Yaman scale, used in Indian classical music, characterized by a raised fourth.
RagaBhairav: Scales the pitch to the nearest note in the Raga Bhairav scale, used in Indian classical music, with flattened second and seventh degrees.
Hijaz: Scales the pitch to the nearest note in the Hijaz scale, common in Middle Eastern music, characterized by a raised third.
InSen: Scales the pitch to the nearest note in the In Sen scale, a Japanese pentatonic scale with a minor third and a diminished fifth.
Yo: Scales the pitch to the nearest note in the Yo scale, a Japanese pentatonic scale often used in traditional music.
Yu: Scales the pitch to the nearest note in the Yu scale, another Japanese pentatonic scale with a distinctive sound.
Zhi: Scales the pitch to the nearest note in the Zhi scale, a Chinese pentatonic scale used in traditional music.
Altered: Scales the pitch to the nearest note in the altered scale, used in jazz and characterized by its altered fifths and ninths.
LydianDominant: Scales the pitch to the nearest note in the Lydian dominant scale, which has a raised fourth and a flattened seventh.
HungarianGypsy: Scales the pitch to the nearest note in the Hungarian gypsy scale, featuring raised fourth and seventh degrees.
Egyptian: Scales the pitch to the nearest note in the Egyptian scale, a pentatonic scale with unique intervals giving it a distinct sound.
TET_4: This scale divides the octave into 4 equal parts, each 300 cents apart. It results in a very distinct and sparse scale.
TET_5: This scale divides the octave into 5 equal parts, each 240 cents apart. This creates wide intervals and can be used for unique harmonic structures.
TET_7: Scales the pitch to the nearest note in the 7-tone equal temperament scale, which divides the octave into 7 equal parts, each approximately 171.43 cents apart.
TET_8: Scales the pitch to the nearest note in the 8-tone equal temperament scale, which divides the octave into 8 equal parts, each 150 cents apart.
PierrotTuning: A microtonal scale that divides the octave into 13 steps, each approximately 92.31 cents apart.
TET_19: Scales the pitch to the nearest note in the 19-tone equal temperament scale, which divides the octave into 19 equal parts, each approximately 63.16 cents apart.
TET_22: This scale divides the octave into 22 equal parts, each approximately 54.55 cents apart. It provides a good approximation of certain just intonation intervals.
TET_31: Scales the pitch to the nearest note in the 31-tone equal temperament scale, which divides the octave into 31 equal parts, each approximately 38.71 cents apart.
Diminished: Scales the pitch to the nearest note in the diminished scale, also known as the half-whole scale, which alternates between half steps and whole steps.
Augmented: Scales the pitch to the nearest note in the augmented scale, which alternates between minor thirds and half steps, creating a symmetric, exotic sound.
DoubleHarmonic: Scales the pitch to the nearest note in the double harmonic scale, also known as the Byzantine scale, featuring a distinctive exotic sound with raised fourth and lowered seventh degrees.
BohlenPierce: Scales the pitch to the nearest note in the Bohlen-Pierce scale, which divides the tritave (perfect twelfth) into 13 equal parts, creating a unique microtonal system.
Tritone: Scales the pitch to the nearest note in the tritone scale, which alternates between half steps and minor thirds.
Hexatonic: Scales the pitch to the nearest note in the hexatonic scale, a six-note scale that can have various symmetric patterns.
Prometheus: Scales the pitch to the nearest note in the Prometheus scale, a six-note scale used by Scriabin, featuring unique intervallic structures.
AJLAB: Scales the pitch derived from the Fibonacci sequence, where each number is the sum of the two preceding ones, they create a unique and intriguing set of pitches.

8 Preset Modes

Syncussion SY-4X VST Plug-In

The Syncussion offered A, B, C, D, E and F Modes which are a predefined setting for Oscillators Pitch, Frequency Modulation, Volume levels and other modulation sources.
SY-4X adds two additional modes G and H.
Here is a description of each Mode, each one of them is better at producing certain types of sounds than others, experiment with them and you will find out!

Mode List

Mode A

Oscillator 1 outputs a triangular waveform to the VCF. Simple and effective, particularly nice in Keyboard Mode...

Mode B

Oscillator 1 modulates the frequency of Oscillator 2, both triangular waveforms. Oscillator 2 outputs to VCF. Those classic Syncussion percussions...

Mode C

Oscillator 1 and Oscillator 2, both triangular waveforms, output to VCF, with Oscillator 2 set to a higher frequency.

Mode D

Oscillator 1 and Oscillator 2 are modulated by envelope generator 2. Both triangular waveforms output to VCF, with Oscillator 2 set to a higher frequency. Similar to Simmons, can produce nasty kicks...

Mode E

Oscillator 1 modulates the frequency of Oscillator 2. Oscillator 2 is set to a pseudo SAW waveform and a higher frequency, outputting to VCF, which is set to a higher cutoff frequency. Close the filter for the Prince "explosion sound" heard in concerts in the early '80s...

Mode F

Noise generator only, outputs to VCF. Awesome while controlling the tuning—the key is to have one hand on the control while playing, so you can instantly shorten a long decaying envelope, making it really expressive...

Mode G

Oscillator 1 and Oscillator 2 are cross-ring modulated. Both OSCs are set to produce a square waveform, output to VCF. An extra TUNE slider is available to control the frequency of OSC2 independently and within a wider range than the offset slider. Super nice for creating cymbal or bell sounds...

Mode H

Oscillator 2 is synced to Oscillator 1. Oscillator 2 is set to a pseudo SAW waveform and outputs to VCF. An extra TUNE slider is available to control the frequency of OSC2 independently and within a wider range than the offset slider. Who doesn't like SYNC? SYNC drum sounds are nice too...

Note: Channel 8 has an optional switch to turn Mode A into a new preset, where Oscillator 1 and Oscillator 2, both square waveforms, output to VCF. Channel 2 and Channel 6 can add direct noise injection (pre-filter) into the VCA. The noise can also be modulated by an S&H circuit, with its frequency dependent on the current tuning (crunchy noise). Lastly, Channel 6 in Drum Kit mode has three notes assigned to the trigger; two modulate the decay to be shorter, and one maintains the current value, making it useful for Hi-hat open/close action or other creative uses!

SY-4X Syncussion Videos

Some videos made during development time posted on Instagram

Note that those low res video snippets were made from unfinished dev versions, and many things have changed since, might be still useful though...

Sound Demos coming up...

Product Demos by Aly james

You can already check out a bunch of live demos from my instagram ;)

GLOBAL FEATURES

Circuit Model: Accurately reproduces the Syncussion design and sound.
4 Independent Syncussion modules.
CMOS based oscillators for authentic tone generation.
Multi Outputs routing capability.
Drum Kit or Keyboard Modes.
Modeled VCF Filter topology, 2-pole spreading low-pass filter with extra user control.
Up to 60 optional pitch scaling rules to choose from.
Optional Berserk Mode with 2 types of distortion.
Most parameters respond to automation.
Settings and preset browser pages.
Improved VST3 MIDI support (e.g., can receive MIDI 2.0, enable Ableton Live's "External Instrument rack" inputs detection, etc.).
Up to X16 Oversampling

COMPATIBILITY

: Windows 10 and higher
PC: 64bit VST3 compatible host.
Not supported but has been proved to work on Windows 7
: Mac OS 10.14 and higher (64bit)
Mac: 64bit VST3 or Audio-Unit compatible host.
Universal 2 binary: works natively on both Silicon and Intel based Mac.
Not supported but has been proved to work down to Mac OS 10.10

Protools: Avid Protools only supports its proprieratary format AAX at the moment but you can still easily load an AU or VST plugin with the help of a VST/AU host plugin, some popular solutions are DDMF Metaplugin or BlueCat's Patchworks, others might be available that I am not aware of yet.

SY-4X Syncussion Manual

Get amazing details about SY-4X Syncussion!

SY-4X Syncussion MANUAL.

SY-4X Plug-In User Manual

Change Log

UPDATES HISTORY

You can check your current version on the GUI.

09/13/24 - v1.0.2

Fix - MIDI-learned parameter (if any) assignments are now correctly saved with the session.
Fix - MIDI Custom Map for channels 6, 7, and 8 are now properly assigned to custom drum notes.
Fix - Sweep Envelope now correctly updates EG2 decay time (corrected missing update from tuning to EG2).
Fix - Trigger velocity now correctly affects EG2 decay time.
corrected envelope calculation.
Fix - Mode D: corrected pitch modulation.
Pitch envelope CV in Mode D was using wrong virtual resistor value resulting in the pitch going around one octave higher than original factory setting.
New Feature - Copy and Paste channel settings, allowing users to easily share settings between channels or copy/paste between presets.
Added - New parameter: VCF Poles 1:1 Ratio.
optional equal resistance for the filter's CV resistors, makes the Spread parameter even more interesting by bringing poles closer.
Added - New parameter: LFO Trigger Reset (resets LFO phase on trigger).
thanks to DSP this mod still keeps S&H unaffected.
Added - New parameter: EG Fast Attack.
bypasses envelope attack smoothing for a sharper, more "clicky" sound, adjust as needed. Set to "Hardware Reset" default.
Added - New parameter: Decay Sense.
an extra custom control to increase dynamic decay control, without this extra control there is still a slight decay change from trigger envelope but now you can increase it independently.
Tweak - Sweep Envelope now outputs a clipped voltage when set to extremely fast, simulating OPAMP driven close to supply rail more accurately.
Adds a noticeable short "tuned snap" at the beginning of an ultra fast sweep that was missing before.
Change - Hold reset value changed, also reflects when using "Hardware Reset".
-default EG2 response is now closer to hardware with that setting - a bit less curvy than previously set default value, tweak to taste.
Tweak - Minor GUI changes to accommodate for new LFO sync param and additional settings.
-Mode Trigger switch is now closer to the left-side Mode knob & CH8 Custom Mode A switch has been moved to the right. Set panel redesigned accordingly.
Tweak - Minor GUI changes: Some GUI sliders response change: Log taper instead of Linear.
I say some because for example, I have kept LFO sliders Linear because it's easier to control that way, the log response makes sense on some parameters and in case you were used to the hardware it will make the experience more familiar even though some parameters have extented range.

08/11/24 - v1.0.2

Initial release.
info - Only 15 Presets are available for the first release week, more will come just after, you should tweek it anyway ;)

Machine	Format(s)	Architecture(s)	Native Processor(s)	OS Supported	Note
PC	VST3	X64	INTEL	Windows 10 or higher
Mac	VST3, AU	X64	INTEL/ARM	Mac OS-10.14 or higher