Equalizer: Parametric Audio Filter

shotcut
February 22, 2022

Applies a fully parametric equalizer with five adjustable sections, allowing precise control over specific frequency ranges.
Unlike graphic equalizers, this filter lets you choose which frequencies are affected, how much they are boosted or cut, and how wide each adjustment is.

This filter operates in the frequency domain.

Structure overview

The filter is divided into five EQ sections:

  1. Low Shelf – broad control of low frequencies
  2. Band 1 – fully parametric mid band
  3. Band 2 – fully parametric mid band
  4. Band 3 – fully parametric mid band
  5. High Shelf – broad control of high frequencies

Each section affects a different part of the spectrum and serves a distinct purpose.

Parameters

Low Shelf

Affects all frequencies below the selected cutoff frequency.

Frequency (20.0 - 20 000.0 Hz)

Sets the point below which frequencies are boosted or attenuated.

Examples: rumble, bass weight, low-end warmth

Gain (-30.0 to +30.0 dB)

Controls how much the low frequencies are boosted or cut.

Slope (0.0 - 1.0)

Controls how gradually the shelf transitions.

Band 1 / Band 2 / Band 3 (Parametric bands)

Band 1, Band 2, and Band 3 are three independent parametric mid-frequency filters.
Having multiple mid bands allows you to:

For example:

Each band contributes one “piece” to the final EQ curve.

These are fully adjustable midrange bands, typically used for detailed tone shaping.
Each band has the same controls.

Frequency (20.0 - 20 000.0 Hz)

Selects the center frequency affected by the band.

Gain (-30.0 to +30.0 dB)

Controls how much the selected frequency range is boosted or attenuated.

Bandwidth (0.0 - 4.0 octaves)

Controls how wide the affected frequency range is.

Audible note:
Narrow bandwidth with high gain can introduce audible resonance or ringing.

High Shelf

Affects all frequencies above the selected cutoff frequency.

Frequency (20.0 - 20 000.0 Hz)

Sets the point above which frequencies are boosted or attenuated.

Gain (-30.0 to +30.0 dB)

Controls brightness and high-frequency energy.

Slope (0.0 - 1.0)

Controls how sharply the shelf transitions.

Keyframes (grouped)

All parameters are keyframed together.

This allows:

Channel selection (toggle buttons)

Determines which audio channels the equalizer is applied to.
Buttons are toggle switches.

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Available buttons depend on the project’s audio channel configuration: Settings > Audio Channels.

Important note:

Independent equalization per channel requires adding separate instances of the filter.

Auditory characteristics

Recommended use cases

Usage notes and tips

Limitations