VCV Rack FM Patches: Kitchen Sink and Pigeon Plink Experiments

How can you patch Kitchen Sink and Pigeon Plink in VCV Rack for evolving FM sounds, feedback loops, ratio modulation and generative sequences?

Introduction: FM as a patching system

Kitchen Sink and Pigeon Plink are especially interesting when you stop treating frequency modulation as a single connection between two oscillators. Their many modulation options let you build patches in which pitch, waveform, modulation depth, feedback and amplitude influence each other.

The six experiments in this article are based on the Kitchen Sink 1–3 and Pigeon Plink 1–3 patches from Signal Path. They begin with relatively straightforward FM voices and progress toward more complex feedback and modulation systems.

If you have the original downloadable presets, load each one as a reference and compare your patch with the descriptions below. If you are building from scratch, use the instructions to understand the signal flow rather than trying to reproduce every knob position immediately.

The key is to listen to one relationship at a time. FM patches can become complex very quickly, and understanding why a sound changes is more useful than simply discovering an interesting preset.

Patch 1: Kitchen Sink 1 — Envelope-controlled through-zero FM

Main idea: Use a sequenced carrier and modulator, with an envelope controlling FM depth and an LFO animating wave folding.

This first patch is a useful introduction to combining several of Kitchen Sink's features.

Signal flow

• The sequencer's pitch output is connected to both Kitchen Sink modules.
• The sequencer's Gate output is connected to the Gate inputs of both modules.
• The left Kitchen Sink acts as the modulator.
• The right Kitchen Sink acts as the carrier.
• The carrier uses linear through-zero FM.
• The carrier's ADSR envelope modulates through-zero FM depth.
• Both oscillators use the Fold waveform setting.
• An LFO in the lower cabinet modulates the carrier's fold depth.

The Gate connections are worth retaining even though the carrier is the main voice whose envelope is activated in the initial setup. Having the Gate signal available at both modules makes it easy to experiment with the modulator's envelope behaviour as well.

How to explore the patch

Start by listening with the carrier's envelope controlling FM depth. Change the envelope's attack and decay settings and notice how the spectrum evolves during each note.

Next, experiment with the modulator's envelope. Depending on the configuration, changing the modulator's behaviour can alter the way the carrier is driven and the character of the resulting sound.

Then try different waveforms on both oscillators. The carrier waveform directly affects the sound you hear, while the modulator waveform influences the frequency changes applied to the carrier.

Finally, reduce or disable the LFO modulation of fold depth. Compare the more stable tone with the version in which wave folding changes continuously.

What you learn

This patch demonstrates that an envelope does not have to control only amplitude. By assigning it to FM depth, you make the spectral complexity of a note change over time.

The LFO adds a second layer of movement, so the sound can continue evolving even when the envelope has reached a relatively stable stage.

Further experiment: Keep the sequence unchanged and compare a sine modulator with a saw modulator. This isolates the effect of the modulator waveform.

Patch 2: Kitchen Sink 2 — A complex oscillator feedback loop

Main idea: Route the carrier's audio back into the modulator and use separate LFO outputs to animate the feedback and FM depth.

The second patch moves beyond the conventional arrangement in which a modulator drives a carrier in one direction.

Here, the carrier's output is routed back into the modulator through a VCA. The result is a more complex feedback relationship.

Signal flow

• The right Kitchen Sink is the carrier.
• The carrier's output is connected to a VCA.
• The VCA's output is routed into the left Kitchen Sink, where it serves as a linear FM modulator.
• The LFO's triangle output modulates the VCA attenuation.
• The same triangle output also modulates the linear FM depth.
• The LFO's saw output modulates the oscillator FM feedback inside the left Kitchen Sink.
• The resulting audio is sent through a plate reverb.

In this patch, the carrier becomes part of the signal driving the modulator, and the modulator's behaviour in turn affects the carrier. The audio signal therefore participates in a more complex interaction than in a simple one-way FM patch.

Why the VCA matters

The VCA is important because it controls how much of the carrier's output reaches the modulator's FM input. Without this attenuation stage, the feedback signal might drive the modulation too strongly for the particular settings you are using.

The VCA also gives the LFO a way to animate the amount of feedback entering the system. Because the LFO triangle simultaneously changes the attenuation and the FM depth, two important aspects of the patch evolve together.

Meanwhile, the saw output changes the internal oscillator feedback of the left Kitchen Sink. This adds another layer of movement rather than merely changing the external FM signal.

How to explore the patch

1. Start with low attenuation of the feedback path.
2. Slowly increase the amount of carrier signal reaching the modulator.
3. Reduce the FM depth if the result becomes too dense or difficult to hear clearly.
4. Adjust the LFO frequency and listen to the rate at which the timbre changes.
5. Change the relationship between the LFO rate and the sequencer clock.
6. Experiment with the octave and ratio settings of both Kitchen Sink modules.
7. Adjust the envelopes to introduce additional time-dependent changes.
8. Finally, compare the dry signal with the plate reverb.

For further experiments, the preset Kitchen Sink 3 provides another starting point for exploring octave and ratio settings in this patching approach.

What you learn

The main lesson is that feedback can turn a pair of oscillators into a more interactive sound-generating system. Instead of simply adding more modulation sources, you use the output of one part of the patch to influence another part of the same system.

Because the result is sensitive to levels, tuning and modulation depth, make small adjustments and listen carefully. If you want to understand the effect of one change, avoid adjusting all the feedback and modulation controls simultaneously.

Patch 3: Kitchen Sink 3 — Exploring carrier and modulator tuning

Main idea: Use the third Kitchen Sink preset as a focused experiment in tuning relationships and timbral interaction.

The original Kitchen Sink examples invite you to explore different octave and ratio settings on both modules. Kitchen Sink 3 is a useful reference point for this stage of experimentation.

Keep the basic patching arrangement familiar, then change the tuning relationship between the carrier and modulator.

Experiment A: Change the ratio

Begin with the existing settings and alter the carrier-to-modulator ratio. Listen for changes in the density and harmonic character of the output.

Experiment B: Change the octave relationship

Keep the ratio setting fixed while changing the octave or fine tuning of one oscillator. This helps you distinguish the effect of changing a tuning control from the effect of changing the ratio control.

Experiment C: Change the modulation timing

Compare slow and fast LFO rates, and alter the relationship between the LFO and sequencer clock. The same sound source can behave very differently when its timbral changes move slowly across a sequence or occur several times during each note.

What you learn

FM sound design depends on several interacting relationships: carrier and modulator frequency, modulation depth, waveform, envelope and the timing of external modulation. A systematic approach makes it easier to understand which relationship is responsible for a particular change.

Patch 4: Pigeon Plink 1 — Sample-and-hold ratio modulation

Main idea: Use a sample-and-hold signal to change the FM ratio in steps, while an ADSR envelope shapes the output amplitude.

Pigeon Plink's continuous Ratio control opens up another approach to FM patching. Rather than tuning the modulator manually for every experiment, you can modulate the ratio itself.

In this patch, an LFO and sample-and-hold combination generates changing values that control the Ratio parameter.

Signal flow

• The VCO in the lower cabinet acts as the modulator.
• Pigeon Plink acts as the carrier.
• The sequencer sends the V/Oct pitch sequence to Pigeon Plink.
• An LFO and sample-and-hold combination generates changing CV values.
• The sample-and-hold signal passes through a VCA before reaching the Ratio CV input.
• The ADSR envelope controls Pigeon Plink's VCA.
• The LFO in the upper cabinet clocks the sample-and-hold, ADSR and sequencer.
• Pigeon Plink's Ratio stepping mode is set to DX11.

The VCA provides control over the amount of ratio modulation. This is useful because the raw CV range from a sample-and-hold source may be too broad for the timbral changes you want.

How to explore the patch

Start with a restrained amount of sample-and-hold modulation. Listen to the sequence and notice how the changing ratio affects the timbre even when the sequencer's pitch pattern remains the same.

Then adjust the VCA attenuation. A small modulation range can create subtle changes, while a larger range can move the ratio through more dramatic relationships.

Try different stepping modes. DX11 is the starting point in this preset, but Octaves and None can produce very different patterns of change.

For a more melodic variation, patch the sequencer's V/Oct output to the modulating VCO as well as to Pigeon Plink. Now the carrier and modulator follow the same pitch succession, while the Ratio control continues to determine their frequency relationship.

What you learn

This patch separates two useful kinds of movement:

• The sequencer controls the pitch of the voice.
• The sample-and-hold system changes the FM relationship.

Keeping these functions distinct makes it easier to build sequences in which the notes remain recognizable while the timbre changes from step to step.

Patch 5: Pigeon Plink 2 — Direct LFO control of ratio and FM depth

Main idea: Remove the sample-and-hold and let an LFO change both the ratio and FM depth continuously.

Pigeon Plink 2 simplifies the modulation system by removing the sample-and-hold module. The LFO now modulates the Ratio parameter directly through a VCA.

The Ratio stepping mode is set to Octaves. The same LFO also modulates linear FM depth.

Signal flow

• The sequencer supplies the pitch sequence to Pigeon Plink.
• The LFO passes through a VCA and modulates the Ratio parameter.
• The LFO also modulates linear FM depth.
• The LFO is set to unipolar operation using its Offset control.
• The ADSR envelope continues to shape the output through Pigeon Plink's VCA.

The key difference from Pigeon Plink 1 is the continuous movement. Instead of selecting a new ratio at each sample-and-hold event, the LFO sweeps the Ratio parameter over time.

How to explore the patch

First, reduce the LFO's influence on Ratio and listen to a narrow movement around the starting setting. Then increase the modulation range.

Next, reduce the LFO's influence on FM depth. Compare ratio movement alone with the combined movement of ratio and depth.

Because the same LFO controls both parameters, the spectral changes are linked. You can experiment with their relative modulation amounts to create a more restrained or more dramatic result.

Try changing the LFO rate independently of the sequencer clock. A slow sweep across a repeating note sequence produces a different effect from a fast sweep that changes several times during a note.

What you learn

Pigeon Plink can turn a simple LFO into a multi-dimensional sound-design tool. Modulating Ratio and FM depth together creates a more complex result than modulating either parameter alone.

The unipolar setting is also useful to understand: it changes the range of the LFO signal, which affects how the modulation moves through the parameter's range. It does not itself determine whether the oscillator's audio frequency is positive or negative.

Patch 6: Pigeon Plink 3 — Two FM oscillators with different ratio systems

Main idea: Use one Pigeon Plink as the modulator and another as the carrier, with different ratio-stepping schemes and shared modulation.

The third Pigeon Plink patch replaces the modulating VCO with a second Pigeon Plink. This gives you two FM-capable modules in the same patch.

Both modules share the sequencer's pitch modulation and the same envelope. Their Ratio parameters are controlled by the same LFO/VCA combination used in the earlier Pigeon Plink patches.

The important difference is that the two oscillators use different stepping modes:

• The left Pigeon Plink, acting as the modulator, uses DX7 stepping.
• The right Pigeon Plink, acting as the carrier, uses Octaves stepping.

A delay is added before the plate reverb.

Signal flow

• The left Pigeon Plink provides the modulating signal.
• The right Pigeon Plink provides the carrier output.
• Both modules receive the same sequencer pitch modulation.
• Both modules receive the same envelope.
• The LFO/VCA combination modulates the Ratio of both modules.
• The modulator's Ratio uses DX7 stepping.
• The carrier's Ratio uses Octaves stepping.
• The audio passes through delay and then plate reverb.

Why use different stepping modes?

The two Ratio controls share a modulation source, but their stepping modes are different. Consequently, the same changing CV does not necessarily produce the same sequence of ratio values on both modules.

This is an effective way to create a more complex interaction without introducing another LFO or random source. The two oscillators respond differently to a shared control signal because their ratio-stepping schemes differ.

How to explore the patch

Start by listening to the patch with the delay and reverb at restrained settings. Concentrate on the relationship between the two oscillators.

Then change the stepping mode on the modulator while leaving the carrier unchanged. Listen for changes in the interaction between the two FM stages.

Next, reverse the experiment: keep DX7 stepping on the modulator and change the carrier's stepping mode.

Finally, adjust the shared LFO's rate and the VCA attenuation. You can also compare the sound with the delay bypassed, then introduce delay and plate reverb gradually.

What you learn

This patch demonstrates how complexity can emerge from differences between two related systems. The oscillators share their pitch and modulation sources, but their different ratio-stepping modes lead to different responses.

The delay and reverb add spatial depth, but the essential sound-design idea comes from the two interacting FM stages.

General advice for all six patches

These patches contain several parameters that can influence the sound at the same time. A few practical habits will make experimentation more productive.

Change one relationship at a time. If you change the ratio, FM depth, feedback and waveform simultaneously, it can be difficult to tell which adjustment caused the result.

Use attenuation deliberately. A VCA or attenuator in a modulation path is not merely a volume control. It gives you precise control over how strongly one part of the patch influences another.

Separate pitch from timbre. Keep the sequencer fixed while experimenting with Ratio or FM depth. Once you understand the timbral change, combine the modulation with pitch movement.

Compare waveforms. Try sine waves first when you want a relatively clear starting point, then introduce triangle, saw or folded waveforms to explore more complex results.

Listen to the modulation rate. A slow LFO can create gradual changes across several notes, while a faster LFO can alter the timbre repeatedly within a single note.

Treat effects as the final layer. Delay and reverb can make a patch sound more spacious, but begin with the dry signal so you can understand what the oscillators are doing.

Conclusion: From FM voice to evolving system

Kitchen Sink and Pigeon Plink reward experimentation because they make it possible to combine several kinds of modulation without reducing the patch to a conventional carrier-and-modulator pair.

Kitchen Sink is particularly useful for exploring multiple FM approaches, wave folding, oscillator feedback and envelope-controlled timbre. Pigeon Plink extends the possibilities through its continuous ratio control and selectable stepping schemes.

Together, the six experiments provide a progression from envelope-shaped FM through feedback interaction to generative ratio modulation and two-stage FM systems.

You do not need to reproduce every setting exactly to benefit from the patches. Load the presets if available, understand the signal flow, and then change one relationship at a time. The goal is to develop an ear for how frequency relationships, modulation depth, feedback and timing interact—and to turn those interactions into your own evolving instruments.

Just click here and read more about this topic, and download presets and example files in “Signal Path monthly”.