GyratorFLT Gyrator Filter

The GyratorFLT is a modern tribute to the iconic Gyrator-based equalizers and filters that shaped the sound of the recording industry. Named after the groundbreaking electronic circuit, the GyratorFLT is not just another filter— it is a resonant, dynamic tone-shaping tool designed for precision and musicality.

Historically, Gyrator circuits were introduced as solid-state alternatives to inductor-based equalizers, offering the same warm, rich filtering characteristics without the size and weight of traditional analog components. These circuits found their way into high-end studio equipment, known for their ability to sculpt tone with a unique mix of resonance and clarity.

With GyratorFLT, we bring that classic musical filtering into the modern age as a powerful Rack Extension plugin for Reason. Whether you’re sculpting bass, adding character to midrange frequencies, or giving air to high-end details, this versatile filtering unit delivers vintage-inspired warmth and contemporary flexibility in one intuitive interface.

Gyrator-based equalizers first appeared in the late 1960s and became a staple in high-end studio consoles and outboard gear. Unlike traditional passive EQs, which relied on heavy and expensive inductors, Gyrator circuits emulated inductors electronically, providing a warm yet controllable resonance without unwanted phase shifts.

From classic mixing consoles to boutique parametric equalizers, the Gyrator principle has been used to create highly musical, smooth, and effective tone-shaping tools. Our GyratorFLT is inspired by these designs but extends them into new creative territories—merging the best aspects of equalization and resonant filtering into a single, performance-driven effect.

Dual Parallel Processing : Blend between a resonant EQ path and a filter-based path for ultimate control over your sound.
Bandpass Resonance Control: Stack multiple BP filters for deep, warm resonance or a more surgical tone-sculpting approach.
Advanced Saturation & Drive: Shape harmonics and warmth with multiple saturation and distortion modes.
LFO Modulation: Introduce movement by modulating frequency, resonance, or drive.
Shelving Filters: Add further shape the tone before or after filtering.
Mix between dry and processed signals or Blend between EQ and Filter paths for dynamic sound design.
Feedback Section: Integrated feedback circuit for unique resonant and overdriven.

The GyratorFLT is more than just an EQ or a filter—it’s a creative tone-sculpting machine, inspired by legendary circuits but designed for modern production.

WHAT MAKE GYRATORFLT UNIQUE?

The EQ section provides precise control over gain and frequency, useful for tonal shaping. 

The Filter section introduces the resonance that is key to emulating a gyrator’s analog-style peaks.


Parallel routing offers a rich, hybrid sound with blended characteristics from both modules.

Parallel Routing (EQ + Filter): This isn’t very common in modern filter effects, especially with easy blending options.

Feedback & Modulation Options: By allowing filter cutoff, resonance, or gain modulation, device adds dynamic sound-shaping capabilities that are not always available in standard EQs or filters.

Saturation in Filter Path: This adds warmth and harmonic content, giving it an edge for creative sound design.
GyratorFLT concept will most closely resemble elements from musical EQs or analog-inspired filters, but the combination of parallel EQ + Filter with feedback and modulation makes it distinct. This balance of tonal control and dynamic movement positions it between classic EQ tools and modern modular filters, creating a versatile and creative effect suitable for both sound design and mixing.

GyratorFLT design is inspired by the principles of a gyrator. However, it’s technically a hybrid of EQ and filter effects with added features like modulation, feedback, and blending, which goes beyond the typical behavior of a pure gyrator circuit.

SHELF FILTERS / PARAMETRIC EQ

LOW / HIGH SHELF: Boosts or cuts low frequencies before reaching EQ and Filter.
LOW / HIGH LEVEL: Adjusts the level of the Low/High shelving filters. Boosting the low end can give more body to the signal, making it feel richer and warmer, while cutting the high end can smooth out harshness.
EQ BANDWIDTH: Adjusts the width of the bell EQ curve (0.33 to 3 octaves). Lower values create a sharper focus.
EQ GAIN: Controls the level of the EQ band; influences the bandpass effect when combined with Filter path. Adjust for subtle boosts or cuts. Modulating the gain can introduce subtle changes in amplitude, which adds movement to the signal.

BANDPASS FILTER

RESONANCE Adjust for the sharpness of the bandpass filter peak. Modulating the resonance can dynamically emphasize or de-emphasize the filter’s peak, contributing to a more organic feel.
SLOPE: Switch between 18 & 24 db/Oct filter slope modes
FEEDBACK: Controls the amount of signal fed back into the filter path, increasing intensity.
SATURATION: Adds warmth or harmonic distortion, mimicking non-linear analog characteristics.

MAIN CONTROLS

CENTRAL FREQUENCY: Controls the center frequency of both the EQ and Filter paths (40 Hz - 16 kHz).
Modulating the center frequency can create a sweeping effect, making the sound feel dynamic and evolving. It allows the resonant peak to move across the spectrum, creating a pronounced effect that can evoke a sense of motion.
BLEND: Balances between EQ and Filter in parallel; allows for independent blending of these paths. Make flexibility in fine-tuning the overall sound.
REVERB: Set reverb size at the end of the processed signal
MIX: Blends between the EQ/Filter paths and the dry input signal. This is helpful in cases where a subtle tonal adjustment is needed, keeping some of the original signal intact.
INPUT LEVEL: Adjusts the input level before processing.
OUTPUT LEVEL: Adjusts the final output level.

ENVELOPE FOLLOWER

THRESHOLD: Determines the level at which the envelope follower starts reacting to the input signal.
Lower Values: Make the envelope react to quieter sounds.
Higher Values: Ignore lower-level signals and only respond to louder transients.
ATTACK: Controls how quickly the envelope reacts when the input signal exceeds the threshold.
Short Attack: Creates a snappy, fast response, good for percussive or plucked sounds.
Long Attack: Results in a smoother, more gradual rise, useful for pads or swelling effects.
RELEASE: Determines how long it takes for the envelope to return to zero after the input level drops below the threshold.
Short Release: The modulation follows the transients tightly, making the effect more responsive.
Long Release: Creates a lingering effect where modulation fades out slowly.
AMT: Controls the intensity of the modulation applied to the selected destination.
DESTINATION: Defines which parameter the envelope follower modulates.

LFO

RATE: Determines how fast the LFO oscillates.
SYNC: Synchronizes the LFO rate to the project tempo.
Synced Mode: The rate is locked to musical values (e.g., 1/4, 1/8, 1/16 note, triplets).
WAVEFORM: Defines the shape of the LFO oscillation.
Sine – Smooth, cyclic modulation (good for vibrato, gentle panning).
Triangle – Similar to sine but with linear motion (works well for wobble bass).
Sawtooth (Ramp Up/Down) – Creates rising or falling modulation (useful for rhythmic swells).
Square – Instant jumps between two values (good for choppy effects like tremolo or gate).
INVERT: Invert waveform
AMT: Controls how much the LFO affects the assigned parameter.
DESTINATION: Specifies which parameter the LFO modulates.

Reverb in the mix

1. Spatial Depth & Dimension:
Since the GyratorFLT is a dynamic filter-based effect, adding reverb allows it to blend into a mix with a sense of space. This is especially useful for sound design, synth processing, and percussive elements, making them feel more ambient or larger-than-life.
2. Smoothing Resonances:
If your Gyrator filter settings introduce sharp resonances, a moderate reverb decay can help soften the peaks and make them less harsh. A short room reverb can glue the effect together while retaining clarity.
3. Creating Atmospheric Modulation:
When combined with LFO-controlled filtering, adding a plate or hall reverb can turn simple movements into sweeping ambient textures, great for pads, drones, or experimental processing.
4. Stereo Enhancement:
A stereo reverb tail can help widen the processed signal, making it sound larger and more immersive. If your effect is used for mixing or mastering, a subtle ambient reverb can create depth without overpowering the dry signal.
5. Sculpting Decay & Tail Character:
Depending on the type of pre-filtering (low cut/high cut) and the mix balance, reverb can add a smooth decay to rhythmic filtering, making it work well on synth stabs, leads, or even drum elements.

Using GyratorFLT in Your Mix

1. Enhancing Low-End Warmth
Use a low-band EQ boost with a gentle resonance in the filter path.
Add Low Drive for extra harmonic depth. 
Blend in parallel with dry signal for tight, punchy bass.

2. Sculpting Midrange Character
Apply narrow-band filtering with resonance to carve out specific tones.
Modulate the filter cutoff for a moving, expressive effect.
Use moderate saturation for added presence and edge.

3. Adding High-End Air & Detail
Enable the High Shelf EQ to open up the top-end.
Use the High Bypass to let crisp transients through without distortion.
Introduce subtle feedback resonance for shimmering textures.

4. Creating Rhythmic Filter Effects
Assign the LFO to Frequency or Resonance for a pulsing, sweeping effect.
Sync the LFO Rate to your project tempo for dynamic movement.
Increase the Feedback Amount for resonant, evolving textures.