How to Adjust FFmpeg Superequalizer Bands

This guide explains how to control individual frequency bands using FFmpeg’s native superequalizer audio filter. You will learn the command-line syntax for addressing each of the 18 available frequency bands, how gain multiplier values function, and practical command examples to boost or cut specific audio frequencies.

The Superequalizer Filter Syntax

The superequalizer filter is invoked via the -af (audio filter) flag. It splits audio into 18 fixed frequency bands labeled 1b through 18b.

The general command structure is:

ffmpeg -i input.mp3 -af "superequalizer=1b=1.0:2b=1.0:...:18b=1.0" -c:v copy output.mp3

Understanding Gain Multipliers

Unlike equalizers that measure gain in decibels (dB), the superequalizer filter uses a linear amplification factor:

  • 1.0 (Default): Unity gain (no change to the frequency band).
  • < 1.0: Attenuation / Cut (e.g., 0.5 halves the amplitude; 0.0 completely cuts the band).
  • > 1.0: Amplification / Boost (e.g., 1.5 increases the amplitude by 50%; maximum allowed is 20.0).

You only need to define the bands you want to alter. Any omitted band defaults to 1.0.

Frequency Band Mapping

The 18 bands correspond to the following center frequencies:

  • 1b: 65 Hz (Sub-bass)
  • 2b: 92 Hz (Sub-bass)
  • 3b: 131 Hz (Bass)
  • 4b: 185 Hz (Bass)
  • 5b: 262 Hz (Low-mid)
  • 6b: 370 Hz (Low-mid)
  • 7b: 523 Hz (Midrange)
  • 8b: 740 Hz (Midrange)
  • 9b: 1047 Hz (Midrange)
  • 10b: 1480 Hz (High-mid)
  • 11b: 2093 Hz (High-mid)
  • 12b: 2960 Hz (Presence)
  • 13b: 4186 Hz (Presence)
  • 14b: 5920 Hz (Brilliance)
  • 15b: 8372 Hz (Brilliance)
  • 16b: 11840 Hz (Highs)
  • 17b: 16744 Hz (Ultra-highs)
  • 18b: 20000 Hz (Ultra-highs)

Practical Examples

Boosting Bass Frequencies

To boost low-end frequencies (65 Hz to 131 Hz) while leaving the rest of the spectrum untouched:

ffmpeg -i input.wav -af "superequalizer=1b=1.8:2b=1.5:3b=1.2" output.wav

High-Frequency Roll-off (Cutting Treble)

To cut harsh high-end frequencies above ~8 kHz:

ffmpeg -i input.wav -af "superequalizer=15b=0.7:16b=0.4:17b=0.1:18b=0.0" output.wav

Mid-Scoop EQ Curve

To attenuate midrange mud while slightly elevating low-end punch and high-end air:

ffmpeg -i input.wav -af "superequalizer=1b=1.3:2b=1.2:7b=0.7:8b=0.6:9b=0.7:15b=1.2:16b=1.3" output.wav

Preventing Clipping

Substantial boosts across multiple bands can push audio peaks above 0 dBFS, causing digital distortion. Add the alimiter filter after the equalizer to protect against clipping:

ffmpeg -i input.wav -af "superequalizer=1b=2.0:2b=1.7,alimiter=limit=0.95" output.wav