Best Practices for Programming Unique Sounds on a Moog Sub 37

Best Practices for Programming Unique Sounds on a Moog Sub 37

The Moog Sub 37 occupies a rare space in modern synthesis: a fully analog, paraphonic instrument with a deep modulation matrix that rewards hands-on experimentation. While its factory presets demonstrate the classic Moog voice—fat basses, screaming leads, and warm pads—the instrument’s true potential emerges when you move beyond presets and craft sounds that carry your personal signature. This expanded guide dives into the architecture, modulation techniques, and advanced workflows that allow you to consistently program unique, expressive patches. Every section builds upon the last, providing a systematic approach to sound design that respects the Sub 37’s analog heritage while leveraging its modern control surface. Whether you are producing electronic music, scoring a film, or designing sound effects, these practices will help you extract sounds no one else has heard before.

Understanding the Paraphonic Architecture

Before turning any knob, it is vital to understand how the Sub 37 handles polyphony. Unlike a true polyphonic synthesizer (which gives each voice its own filter and envelope), the Sub 37 is paraphonic. This means it can play up to two notes simultaneously, but those notes share a single filter, amplifier, and envelope generator. The pitch is independent for each oscillator, but the amplitude and timbre are controlled by one common envelope and filter circuit.

What Paraphony Means for Your Patches

Because the filter and amp envelope are shared, playing a two-note chord will cause both notes to open and close together. This can create a cohesive, “breathing” quality that is difficult to achieve on true polyphonic synths. For lead sounds, this means you can play a melody with one hand while adding a harmony note that follows the same contour, giving a sense of motion. For bass patches, paraphony allows you to layer a sub-oscillator (which is always playing the same note as Osc 1) with a second oscillator tuned an octave higher, creating a massive, complex tone. Understanding this limitation—and turning it into a creative tool—is the first step to programming sounds that feel intentional rather than accidental.

Interval and Voice Assignment Tricks

The Sub 37 lets you set the Interval between the two voices via the arpeggiator or the keyboard mode. Setting a fixed interval (like a perfect fifth or a minor third) when playing a single note will trigger the second oscillator at that interval. This is perfect for creating organ-like patches or doubling leads for extra thickness. You can also use the Unison mode (found in the global settings) to stack both oscillators into a single, monophonic voice with doubled pitch. This mode is ideal for aggressive basses and leads that need to cut through a dense mix.

The Signal Flow: A Deep Dive

The Sub 37’s signal path is remarkably simple on paper, but the interaction between its components creates near-infinite complexity. Every knob, switch, and patch point is designed to be touched during performance. The following subsections break down each stage of the signal flow, highlighting techniques that go beyond standard operation.

Oscillators: Beyond Sawtooth

Most patches default to sawtooth waves because they are harmonically rich. However, the Sub 37’s oscillators shine when you explore less common waveforms. A triangle wave provides a smooth, flute-like fundamental that works beautifully for pads and subtle bass. A square wave with pulse width modulation (PWM) introduces a hollow, evolving character that can be dialed in using the Pulse Width knob for Osc 2 (Osc 1 has a fixed pulse width). For an aggressive edge, pulse width modulation can be routed to an LFO or envelope to create a dynamic, “shimmering” effect reminiscent of vintage string machines.

Detuning with Purpose

Detuning Osc 2 against Osc 1 by a few cents creates the classic “fat” sound, but try detuning by a major third or a fifth for a more complex, organ-like detune. Using the Osc 2 Keyboard Reset function (accessible via the global menu) ensures that the detune remains consistent across the keyboard, which is essential for bass lines where tuning stability is critical. Alternatively, turning off keyboard reset allows the detune interval to stretch with pitch, creating a more chaotic, “analog” feel on higher notes.

The Mixer: Saturation as a Sound Design Tool

The mixer section is your first opportunity to shape tone. Each channel (Osc 1, Osc 2, Sub, and Ext In) has its own level control, and pushing any of them into the red zone introduces analog soft clipping. This overdrive compresses the signal slightly and adds even-order harmonics, giving the sound a warm, tubelike quality. For bass patches, push the Sub oscillator level to 10 (the maximum) while keeping Osc 1 and Osc 2 at lower levels—this creates a deep, saturated low end that maintains clarity. For leads, try pushing all three oscillators into the red to create a screaming, saturated tone that cuts through a mix without needing additional distortion pedals.

The Ladder Filter: Slope and Response Modes

The Moog ladder filter is legendary for its ability to self-oscillate at high resonance settings. The Sub 37 offers four selectable filter slopes: 6 dB/oct, 12 dB/oct, 18 dB/oct, and 24 dB/oct. The 24 dB/oct setting is the classic Moog “brick wall” filter that removes high frequencies aggressively, ideal for smooth basses and pads. The 6 dB/oct slope is gentler and preserves more high-end content, giving a brighter, airier sound. The 12 dB/oct and 18 dB/oct settings offer a middle ground that is great for leads that need both body and clarity.

Additionally, you can switch between Low-Pass, High-Pass, and Band-Pass modes. High-Pass mode is often overlooked but is excellent for creating thin, cutting sounds or for filtering out low-end rumble in a busy mix. Band-Pass mode turns the Sub 37 into a vocal-like instrument, perfect for solos that need to sit in a narrow frequency range. Experimenting with these modes in combination with different keyboard tracking amounts (KB CTL AMT) will unlock filter sounds that are distinctly yours.

Mastering the Modulation Matrix

The modulation matrix is where the Sub 37 transforms from a predictable analog synth into a living, evolving instrument. There are eight modulation slots, each with a source, destination, and amount. Understanding how to use these slots creatively is the key to programming sounds that move and respond to your touch.

Essential Source-Destination Pairings

While the manual lists common routings, the truly unique sounds come from unexpected pairings. Here are three assignments that go beyond the basics:

1. LFO 1 (Sample & Hold) to Osc 1 Pulse Width (PWM). This creates random, choppy fluctuations in the square wave’s duty cycle, emulating the sound of an old analog sequencer running out of control. Perfect for industrial or experimental patches.
2. Envelope 2 (EG 2) to Osc 2 Pitch (Fine). Applying a small amount of positive or negative envelope to the pitch of Osc 2 creates a dynamic detune that changes over the course of a note. A positive amount (envelope opens upward) will cause Osc 2 to rise in pitch, creating a “shimmer” effect. A negative amount causes it to drop, adding a subtle “wobble” on the attack.
3. Aftertouch to Filter Resonance. This is a classic expressive technique: pressing harder on the keys increases resonance, making the filter scream or whistle. Dialing in a small amount aftertouch to resonance gives you dynamic control over the filter’s aggression during a performance, making your solos feel alive.

Using the Pitch and Mod Wheels Programmatically

Both the pitch wheel and mod wheel are fully assignable via the matrix. Instead of using them for their default purposes, set the mod wheel to control LFO rate and depth simultaneously, giving you real-time control over vibrato speed or filter wobble. Assign the pitch wheel to the mixer level of the Sub Oscillator, so moving the wheel from left to center brings in a deep bass layer, and from center to right adds more brightness via Osc 2 level. This transforms a simple patch into a performance instrument.

Clock-Synced Modulation for Rhythmic Movement

The LFOs and arpeggiator can be synced to MIDI clock or an internal tempo. Setting LFO 2 to a dotted-eighth note division and routing it to filter cutoff creates a rhythmic “pump” that syncs with your track. Layering this with a second LFO (set to a slow sine wave) modulating the first LFO’s depth creates a complex, evolving filter pattern that never repeats exactly. This technique is especially powerful for pads and ambient textures.

Advanced Programming Concepts

Once you are comfortable with the signal flow and modulation matrix, these advanced techniques will push your sound design into new territory.

Creating Dynamic Basses with the Envelope Follower

The Sub 37 does not have a built-in envelope follower, but you can simulate one by routing the output of an external audio source (like a drum loop) into the External Input, then using the gate output (from the CV/GATE section) to trigger an envelope that modulates the filter. This approach allows your Sub 37 bass to “duck” and “pump” in response to a kick drum, creating sidechain compression effects without any software. Simply patch a dynamic signal (like a click from a drum machine) into the External Input, set the Mixer’s Ext In level to zero (you don’t want to hear the click), and use the resulting gate signal to trigger EG 2. Route EG 2 to filter cutoff with a negative amount, and every kick hit will cause the filter to close, creating a rhythmic ducking effect.

Feedback Patching for Unstable Textures

Patch a cable from the Output jack into the External Input jack. This creates a feedback loop that can range from a mild overdrive to a screaming, chaotic noise. Start with the Mixer’s Ext In level at zero and slowly increase it until you hear the feedback. Use the filter to shape the feedback’s frequency content: a low-pass filter will create a roaring sub-bass feedback, while a high-pass filter yields screeching high-frequency tones. This technique is perfect for sound effects, transitions, and industrial leads. Be cautious with levels to avoid damaging your speakers or ears—use a limiter in your signal chain if possible.

Leveraging the Sequencer for Evolving Patterns

The 64-step sequencer is more than just a note generator. By programming different velocities for each step, and then routing velocity to filter cutoff or LFO rate, you can create sequences that evolve in timbre and intensity. Use the Tie function to create legato slides between steps, emulating a guitarist’s hammer-on. You can also program rests and gates to create syncopated rhythms that interact with the arpeggiator. Recording a sequence with varied gate lengths (short staccato notes mixed with longer sustained notes) creates a humanized feel that machine-gun repetition cannot match.

Building a Signature Patch Step by Step

Let’s apply these concepts by building a specific patch: a “Vocal Resonant Lead” that uses the filter and modulation to mimic a human voice.

1. Oscillators: Osc 1 set to Square Wave with Pulse Width at 50%. Osc 2 set to Sawtooth Wave, detuned +7 cents. This combination provides a harmonically rich foundation with a slight thickness.
2. Mixer: Osc 1 at 6, Osc 2 at 4, Sub at 0. Drive at 30%—enough to add warmth without noticeable distortion.
3. Filter: Set to Low-Pass, 24 dB/oct slope. Cutoff at 40%, Resonance at 60%. KB CTL AMT set to 70% so the filter tracks the keyboard closely, maintaining brightness on high notes.
4. Envelopes: Amp EG: A=5%, D=30%, S=70%, R=20%. Filter EG: A=10%, D=50%, S=30%, R=40%. Set EG Amount to Filter at 80% for a pronounced sweep. The quick attack and moderate decay on the filter envelope creates a vocal “ee-ah” shape.
5. Mod Matrix: Assign LFO 1 (Sine, rate 4 Hz) to Osc 2 Pitch with Amount 3%—this adds a subtle, fast vibrato. Assign Envelope 2 (inverted) to Filter Cutoff with Amount -30%—this causes the filter to close slightly after the initial attack, mimicking a held vowel.
6. Performance Controls: Assign the Mod Wheel to Aftertouch Depth (via the matrix) so that pressing the mod wheel increases the effect of aftertouch on resonance. Now, during a solo, pressing harder on the keys will add more resonance, creating a screaming, vocal-like overtone.

This patch produces a lead sound that breathes, warbles, and screams with human-like inflection. The key is the interplay between the filter envelope and the inverted modulation—something that sounds complex but is simple to set up once you understand the matrix.

Integrating External Gear for Sonic Expansion

While the Sub 37 is a self-contained instrument, its true potential multiplies when connected to external processors and modular systems.

Effect Pedals and Re-amping

Running the Sub 37 through a chain of guitar pedals adds a layer of character that is difficult to emulate with software. A chorus pedal into a delay, followed by a reverb, can turn a simple bass patch into a lush, spacious pad. For aggressive sounds, try a fuzz pedal before the filter input—the fuzz pre-distorts the signal, and the Sub 37’s resonant filter can then further shape the harmonics, creating sounds that are both brutal and musical. Re-amping the synth through a guitar amplifier and recording the result with a microphone adds real tube saturation and room ambiance; this technique is especially effective for adding grit to otherwise sterile sequences.

Modular Integration

The Sub 37’s CV/Gate outputs make it an excellent master controller for a modular synthesizer. You can send pitch CV from the keyboard to a Eurorack oscillator while the Sub 37 plays its own oscillators, creating a layered sound with different timbres per note. Conversely, patch a modular LFO or random voltage source into the Sub 37’s Filter Cutoff CV Input or Pitch CV Input to inject unpredictable, organic modulation that internal LFOs cannot replicate. The ability to cross-modulate between the Sub 37 and modular gear opens up a universe of evolving, never-repeating tones.

Firmware, Calibration, and Patch Management

To keep your Sub 37 performing at its best, stay current with firmware updates. The latest firmware (as of this writing) adds new arpeggiator patterns, improved MIDI Clock behavior, and additional global parameters. Regular calibration of the oscillators and keyboard (accessible via the global menu) ensures tuning stability, especially important when using the Sub 37 in a studio with other analog gear. Additionally, develop a habit of saving patches you like immediately—even if they are rough sketches. The Sub 37’s patch memory is deep, and revisiting a happy accident weeks later can spark new ideas. Consider organizing your patches into banks (Bass, Lead, Pad, FX) to streamline your workflow during performances or sessions.

Programming unique sounds on the Moog Sub 37 is a practice that rewards curiosity and patience. The instrument’s analog circuitry gives it a warmth and immediacy that digital synthesis can only approximate, and its modulation matrix allows for endless exploration. By internalizing its signal flow, mastering the modulation matrix, and integrating external tools, you can transform simple waveforms into complex, expressive textures that define your sonic identity. The most important practice is simple: keep turning knobs, listen critically, and embrace the unexpected. Happy patching.