A modern Windows GUI for Equalizer APO —
parametric EQ, AutoEQ from real headphone measurements, live preview, and hardware PEQ transfer.

Download · Quick start · Features · Build from source · Usage guide

Equalizer APO is the most powerful system-wide equalizer on Windows — but it is configured through text files. Neon Equalizer puts a full-featured, real-time interface on top of it:

• Drag filters directly on the frequency-response graph and hear the result live before saving.
• AutoEQ built in: pick your headphone from 25,000+ community measurements, pick a target curve, and generate a parametric correction in seconds — no external tools.
• Round-trip safe: your existing config.txt is parsed and re-written faithfully, including conditional (If/EndIf) blocks, per-channel filters, comments, and disabled includes.
• Beyond software EQ: push your parametric filters into hardware — USB DACs, dongles, and network streamers with built-in PEQ.

Get the latest build from the Releases page:

Every release ships a SHA256SUMS.txt you can use to verify your download:

Get-FileHash .\Neon-Equalizer-*-Setup.exe -Algorithm SHA256

1. Install Equalizer APO and enable it for your playback device (run its Configurator once).
2. Download and run Neon Equalizer. It asks for administrator permission because Equalizer APO stores its configuration under Program Files.
3. The app auto-detects your APO config folder (or lets you pick it manually).
4. Add filters — or open AutoEQ & Headphones, choose your headphone and a target, and click Run AutoEQ.
5. Preview the result with the built-in player, then hit Save to APO (or enable Auto Save).

The usage guide covers every panel in detail.

• Parametric EQ — unlimited bands with peaking, shelf, high/low-pass, notch, band-pass, and all-pass filters; edit by dragging graph nodes or typing exact values.
• Graphic EQ — fixed-band sliders for broad tonal shaping.
• Per-channel filters — target left/right, center, LFE, and surround channels individually; channel assignments survive save/reload exactly.
• Auto preamp & clipping protection — gain is compensated automatically so boosts never clip.
• Snapshots, undo/redo, and A/B slots — experiment freely and compare two tunings with one click.

• Squig.link browser built in — search 25,000+ headphone and IEM measurements from 140+ reviewer databases, with signature and source filters.
• Reviewer target curves — each reviewer's own preferred targets load automatically, alongside 29 bundled industry targets (Harman, diffuse-field, JM-1, and more).
• Target customizer — tilt, bass, treble, and ear-gain adjustments applied before optimization.
• Off-thread optimizer — AutoEQ runs in a Web Worker with live progress; the UI never freezes, and rig mismatches (711 vs 5128 measurements) are detected before they produce a bad correction.
• FR Tracer — capture a frequency-response graph image and trace it into usable measurement data.

• Live EQ preview — pink noise, white noise, or your own audio files, with the EQ toggleable in real time.
• Surround setup — per-channel gain and delay for speaker configurations, with HRTF support.
• Device switching — apply profiles per playback device, with optional automatic switching.

Push filters straight into devices with onboard parametric EQ:

• USB (HID / Serial) — supported DACs and dongles, including the JDS Labs Element IV / Atom 2 protocol.
• Bluetooth LE — supported true-wireless earbuds.
• Network (LAN) — WiiM / Linkplay streamers and Luxsin devices over your local network.

• Faithful config round-trips — conditional If/EndIf blocks, Eval lines, comments, disabled # Include: directives, and unknown commands are preserved byte-for-byte on save.
• VST plugin & Loudness Correction entries, convolution, delays, and channel routing (Copy) — managed from the Advanced panel.
• Raw config editor — full text editing with parse-back into the visual UI.
• Presets & user-data backup — export/import EQ presets; back up presets, device profiles, snapshots, and settings to a single .zip.
• Auto-updates — installed builds check GitHub Releases and update in place (portable builds notify only).

Requirements: Windows 10+, Node.js 22.12 or newer, and Equalizer APO for real audio output.

The project uses pnpm via Corepack — no global install needed:

corepack enable          # once (run terminal as Administrator the first time)
pnpm install             # install dependencies

To test production-only behavior (the packaged Content-Security-Policy, file:// loading) without a full package step:

$env:NEON_EQ_LOAD_DIST = '1'; pnpm exec electron .

When publishing a release, upload latest.yml and the .blockmap alongside the installer — the in-app updater depends on both.

electron/         Main process — window, tray, IPC, APO detection, auto-updater
src/
  main.js         Renderer entry — UI logic
  components/     Graph, EQ editors, AutoEQ engine, Squig browser, device PEQ
  config/         Equalizer APO config.txt parser + serializer
  dsp/            Shared biquad math (graph + optimizer use identical curves)
  workers/        Off-thread AutoEQ worker
public/targets/   Bundled target curves
assets/icon.svg   Logo source (all icons are generated from this)

The renderer runs sandboxed with a strict production Content-Security-Policy (no eval, no remote scripts). All privileged operations go through validated IPC channels: file access is scoped to the APO config directory and user-selected paths, and network fetches are SSRF-guarded (DNS validated at connect time, redirects re-checked per hop). Remote data — measurements, reviewer configs — is parsed as pure data and never executed.

Found a security issue? Please open an issue or contact the maintainer privately.

Bug reports and pull requests are welcome. Before submitting a PR, please run pnpm test and pnpm build, and keep the app dependency-light — the UI is deliberately vanilla JavaScript (no frameworks).

GPL-3.0 — free to use, study, share, and improve.