Equalizer APO config.txt: Location, Syntax & Commands Explained

You paste a preset into config.txt, save, press play, and nothing changes. Or half of it changes. Or the left channel suddenly gets twice the bass. No error, no warning, no clue.

That silence is by design. Equalizer APO quietly ignores any line it can’t read, so one typo can switch off a whole preset and you’d never know.

This is the reference I wish I’d had: where config.txt lives, how Equalizer APO reads it, every command you’ll actually use, and copy-paste examples for the jobs people search for most. Checked against the official configuration reference for version 1.4.2.

Where is config.txt?

On a default install:

C:\Program Files\EqualizerAPO\config\config.txt

That’s the only file Equalizer APO loads on its own. Every other .txt file in the config folder does nothing until config.txt points to it with an Include: line.

A fresh install ships with 2 lines in config.txt: a Preamp value and Include: example.txt, which loads a demo filter. Switch that Include off before you build your own EQ, or the demo stays in your sound.

You can edit the file in 3 ways:

Tool	Best for
Notepad	Pasting presets, quick fixes
Configuration Editor (ships with Equalizer APO)	Building filters with a live graph; see the Configuration Editor walkthrough
Peace GUI	Sliders and saved presets; it rewrites config.txt for you

If Notepad says you don’t have permission to save, open Notepad as administrator and try again.

How Equalizer APO reads the file

Every line follows one pattern:

Command: Parameters

Four rules decide what you hear:

1. Top to bottom, in order. Each line applies after the one above it.
2. Unreadable lines are skipped silently. That includes misspelled commands and lines starting with #, which is how you write comments.
3. Changes apply on save. On my test PC (Windows 11 24H2, v1.4.2), a saved change was audible within 0.5 to 1.5 seconds. No restart.
4. Scope commands stick. After a Device: or Channel: line, everything below applies only to that device or channel until the next one.

The commands you’ll actually use

Command	What it does	Example
Preamp:	Overall gain in dB. Negative values make room for boosts	Preamp: -6 dB
Filter:	One EQ filter (type, frequency, gain, Q)	Filter: ON PK Fc 300 Hz Gain -2 dB Q 1.1
GraphicEQ:	Frequency/gain pairs; the AutoEQ format	GraphicEQ: 25 6; 40 4.5; 63 3
Include:	Loads another config file	Include: bass.txt
Device:	Limits the following lines to matching devices	Device: Headphones
Channel:	Limits the following lines to channels	Channel: L
Copy:	Mixes or swaps channels	Copy: L=R R=L
Delay:	Delays the selected channels	Delay: 2 ms
Convolution:	Applies an impulse response file	Convolution: room.wav

Advanced users also get Stage:, If:/EndIf: and Eval: for logic based on sample rate or channel count. Most setups never need them.

Filter types and what each one does

The Filter: line takes a type code. These cover almost every preset you’ll find:

Code	Type	Needs	Use it for
PK	Peaking	Fc, Gain, Q	Boosting or cutting one region (the workhorse)
LS / LSC	Low shelf	Fc, Gain (Q optional with LSC)	Raising or lowering all the bass
HS / HSC	High shelf	Fc, Gain (Q optional with HSC)	Treble and “air”
HP	High-pass	Fc	Removing rumble below a frequency
LP	Low-pass	Fc	Removing everything above a frequency
NO	Notch	Fc	Killing one narrow tone, such as hum
BP	Band-pass	Fc	Keeping one band only (no gain)

The filter number (Filter 1:, Filter 2:) is ignored, so gaps or duplicates don’t matter. The format matches Room EQ Wizard’s “Generic” export, which is why REW and AutoEQ files paste straight in.

The 5 silent failures

When a preset does nothing, one of these is usually the reason:

1. A typo in the command. Fliter: or a missing colon gets skipped without warning. Copy commands exactly.
2. A Device line above it that doesn’t match. Everything below a non-matching Device: line is ignored. This catches people who paste a preset under someone else’s device name.
3. Two presets stacked. Paste a second preset without deleting the first and both apply. Preamps add up too: when several Preamp lines apply to the same channel, Equalizer APO adds them together.
4. The file isn’t included. bass.txt in the config folder does nothing unless config.txt has Include: bass.txt.
5. The install, not the file. If Preamp: -15 dB doesn’t make your music quieter, no line in this file will work. Open the Device Selector and re-tick your device.

Copy-paste examples

A clean switchboard for presets

Keep each preset in its own file and switch with one line:

Preamp: 0 dB
Include: balanced.txt
# Include: bass.txt
# Include: fps.txt

Move the # to change preset. Your preset files never get overwritten.

Different EQ per device

Device: Headphones
Include: balanced.txt

Device: Speakers
Preamp: -4 dB
Include: laptop.txt

The Device: text is a set of words that must all appear in the device name, connection name or ID. Separate alternatives with ;, and use Device: all to go back to every device.

Fix a quiet left or right side

Channel: R
Preamp: -2 dB
Channel: all

This lowers the right channel by 2 dB. End with Channel: all so later lines hit both sides again.

Swap left and right

Copy: L=R R=L

Assignments on one line use the audio from before the line ran, so this swaps cleanly.

Turn stereo into mono

Copy: L=0.5*L+0.5*R R=0.5*L+0.5*R

Useful if you’re deaf in one ear or a recording is hard-panned.

EQ your microphone separately

Device: Microphone
Preamp: +6 dB
Filter: ON HP Fc 80 Hz

The microphone must be ticked on the capture side of the Device Selector first. Full steps are in Equalizer APO microphone settings.

Bass and subwoofer setups

If you run 5.1 or 7.1 speakers, it’s tempting to put bass filters only on the LFE (subwoofer) channel. The official reference advises against it: many systems redirect bass after Equalizer APO has processed the audio, so LFE-only filters miss part of it. Apply low-frequency filters to all channels.

Back up and reset

• Back up: copy the whole config folder somewhere safe. That’s every preset and setting.
• Reset to flat: replace config.txt with a single line, Preamp: 0 dB.
• Restore: paste the folder back.

config.txt FAQ