Boost Sub-Bass in FFmpeg Using asubboost

This article explains how to use the asubboost audio filter in FFmpeg to enhance low-frequency sub-bass in your audio and video files. You will learn the key parameters of the filter, understand how they affect your sound, and see practical command-line examples to easily integrate sub-bass boosting into your media processing workflow.

The asubboost filter works by generating low-frequency harmonics and mixing them back into the original audio signal. To use it, you apply the -af (audio filter) flag in your FFmpeg command followed by the asubboost filter and its parameters.

Basic Syntax and Parameters

The basic structure of the filter is: asubboost=parameter1=value1:parameter2=value2

Here are the most important parameters you can adjust to tune your sub-bass:

  • boost: Controls the sub-bass boost level. The range is from 1.0 to 10.0 (default is 2.0). Higher values yield a stronger bass effect.
  • cutoff: Sets the cutoff frequency (in Hz) for the low-pass filter. Only frequencies below this threshold are boosted. The range is 50 to 150 Hz (default is 60).
  • wet: Adjusts the volume of the boosted (wet) signal. The range is 0.0 to 1.0 (default is 1.0).
  • dry: Adjusts the volume of the original (dry) signal. The range is 0.0 to 1.0 (default is 1.0).
  • decay: Controls the decay time of the sub-bass boost. The range is 0.0 to 1.0 (default is 0.0). Increasing this adds a longer, lingering bass tail.
  • feedback: Controls the feedback level. The range is 0.0 to 1.0 (default is 0.9).

Practical Command Examples

1. Standard Sub-Bass Boost

To apply a standard bass boost to an audio file using the default cutoff frequency of 60 Hz but increasing the boost level to 4.0, use the following command:

ffmpeg -i input.mp3 -af "asubboost=boost=4.0" output.mp3

2. Deep Sub-Bass Boost (Low Cutoff)

If you only want to target the deepest sub-bass frequencies (below 50 Hz) and give them a heavy boost, lower the cutoff frequency:

ffmpeg -i input.wav -af "asubboost=boost=6.0:cutoff=50" output.wav

3. Punchy Bass with High Cutoff

To target a slightly wider range of bass frequencies (up to 90 Hz) while maintaining a balanced mix between the original audio and the boosted bass, you can adjust the cutoff, dry, and wet parameters:

ffmpeg -i input.m4a -af "asubboost=boost=3.5:cutoff=90:dry=0.9:wet=0.8" output.m4a

4. Adding Decay for a Boomy Bass Effect

To create a lingering, boomier sub-bass sound, increase the decay parameter:

ffmpeg -i input.mp3 -af "asubboost=boost=5.0:cutoff=70:decay=0.4" output.mp3