Audio Equalizer (3-Band)

AudioEqualizer3Band is the built-in answer to "this generated track sounds muddy" or "this voiceover needs presence." It's a proper three-band equalizer - low shelf, peaking mid, high shelf - that reshapes the frequency balance of an AUDIO tensor. It's the newest and most obviously experimental member of the audio family, added to ComfyUI core in February 2026, and the EXPERIMENTAL tag on it is worth taking seriously.

"3-band" tells you the shape: one control for the bass shelf, one for a midrange bump or cut, one for the treble shelf. It's a simplified EQ, but that's not a limitation for what most ComfyUI audio work needs. Generative audio comes out with a characteristic muddiness in the low-mids and a dullness on top; a bass shelf adjustment plus a treble shelf lift fixes more of that than you'd guess. You're not mixing a record here, you're fixing the sound of a model.

How it works

Under the hood it uses torchaudio's biquad filters - bass_biquad, equalizer_biquad, and treble_biquad - applied in sequence: low shelf first, then the mid peaking filter, then the high shelf. It's real filtering, not a tone knob approximation. The filters run only when a band's gain is non-zero, so a flat (all 0 dB) setup passes audio through untouched.

The inputs that matter - and honestly, you only need to touch the gains:

• low_gain_dB (FLOAT, default 0, range −24 to +24) - bass shelf. Boost for warmth, cut to de-mud. The low_freq (default 100 Hz, 20–500) sets where the shelf pivots.
• mid_gain_dB (FLOAT, default 0, range −24 to +24) - midrange peaking filter. Cut around 300–800 Hz to clear up boxiness, or boost around 2–4 kHz for vocal presence. mid_freq (default 1000 Hz) is the center, and mid_q (default 0.707) is the bandwidth - lower Q = wider cut/boost.
• high_gain_dB (FLOAT, default 0, range −24 to +24) - treble shelf. Boost to add air and detail. high_freq (default 5000 Hz) sets where it starts.

Inputs and output

• audio (AUDIO) - the track to EQ.
• The three gain fields plus their frequency/Q settings, as above.
• AUDIO (output) - the filtered track.

Getting it

Ships with ComfyUI core since February 2026 - update to any core from that date and it's there. No install, no models.

Common issues

The experimental label is honest: the band structure is fixed and the filter topology is simple, so this isn't surgical. Expect broad tonal shaping, not fix-your-bad-recording precision. The biggest beginner trap is over-boosting - +12 dB on the bass shelf will clip just like any other gain stage, and there's no limiter after the filters. EQ with restraint (a few dB), listen through PreviewAudio, and keep in mind the mid Q default of 0.707 is a nice neutral starting point; widen it if your cut is catching too much neighboring frequency.