Soundstage

System-wide surround sound control for Windows.
A ten-band EQ, real effects, and per-speaker calibration for your 5.1 / 7.1 setup — applied to everything the PC plays, with no virtual cables and no third-party drivers.

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Most PC EQ tools only touch stereo, or make you install a virtual audio cable and reroute your whole system through it. Soundstage doesn't. It ships its own audio engine plugin that Windows loads directly into its audio pipeline, so your EQ, effects and per-speaker tuning apply to every app — Spotify, browsers, games, movies — across a real 5.1 or 7.1 layout. Nothing sits in front of your sound. No cable, no Equalizer APO, no Voicemeeter.

Screenshots

Equalizer & effects	Per-speaker calibration

Features

Equalizer

• Ten-band graphic EQ with a live frequency-response curve
• Preset dropdown with instant apply — plus your own saved presets
• Curated starting points (Flat, Music, Film & Dialogue, and more)

Effects — each is one toggle and one intensity dial

• Bass — weight and drive on the low end
• Warmth / Air — low-shelf and high-shelf tone shaping
• Leveler — a gentle compressor that evens out loud and quiet passages
• Ambience — a tuneable reverb for space and depth
• Night mode — cuts the deep bass that travels through walls and tames sudden peaks, so late-night listening stays audible without waking the house

Surround & per-speaker calibration

• Individual level trim for every speaker — FL, FR, C, LFE, SL, SR, BL, BR — with a per-channel test tone
• Upmix stereo sources to fill your surround speakers
• Bass management: mark speakers "Small" and route their low end to the subwoofer, with an adjustable crossover
• Detects your real hardware layout (2.0 / 5.1 / 7.1) and labels channels accordingly

Everyday

• Live level meters on every speaker, and "now playing" pulled from Windows' media session
• Instant A/B bypass so you can hear exactly what Soundstage is doing
• Runs in the system tray, optional launch-on-boot, volume-key control
• One self-contained installer — no runtime prerequisites

Install

1. Download Soundstage-1.0.0-Setup.exe from the latest release.
2. Run it. It installs to your user folder (no admin needed) and adds Start Menu / desktop shortcuts.
3. Launch Soundstage. To process your audio, open Settings → Run inside Windows' audio engine → Install. This is a one-time step that needs Administrator (it registers the audio plugin), and it's the only time you'll be asked.

That's it — pick a preset, tune your speakers, done.

Removing it: uninstall from Windows "Apps" like any program. To detach just the audio plugin, open Settings → Plugin mode → Uninstall (or run install-apo.ps1 -Uninstall from the install folder). Your original audio setup is restored exactly.

How it works

Soundstage is two pieces that stay cleanly separated:

• The app (WPF host + a WebView2 UI) — what you see and click. It never touches the audio stream itself.
• The audio plugin (SoundstageApo.dll, a Windows Audio Processing Object) — a tiny DSP module Windows loads inside its own audio engine, on the way to your speakers. This is what actually applies the EQ, effects, calibration and bass management.

The two talk through a small shared-memory bridge: move a dial and the app publishes the new settings; the plugin reads them at the top of its next audio buffer. Because the plugin lives in Windows' pipeline rather than in front of it, there's no capture-and-replay, no added device, and nothing to route — which is exactly why it can't break your audio path.

Requirements

• Windows 10 (1809+) or Windows 11, 64-bit
• A playback device with the surround layout you want to control (e.g. an AV receiver over HDMI, configured for 5.1/7.1 in Windows)

Building from source

The app is a self-contained single-file build; the native DSP engine (CMake/MSVC) and the audio plugin build alongside it.

# App + bundled native engine → publish\Soundstage.exe (fully standalone)
dotnet publish src\Soundstage.Shell\Soundstage.Shell.csproj -c Release -r win-x64 `
  --self-contained true -p:PublishSingleFile=true -o publish

# The audio plugin (needs the VS C++ build tools) → native\soundstage-apo\SoundstageApo.dll
pwsh native\soundstage-apo\build.ps1

# The installer (needs Inno Setup 6) → dist\Soundstage-1.0.0-Setup.exe
iscc installer\Soundstage.iss

Troubleshooting

• Effects don't seem to do anything — check the top-right switch isn't on Bypassed, and that plugin mode shows installed in Settings.
• Audio stopped after toggling Dolby Atmos / spatial sound — Windows can disable the effects chain when spatial audio changes. Settings has a Repair button that re-enables it; failing that, uninstall/reinstall plugin mode.
• Speaker test says a channel isn't there — set your device to 5.1/7.1 in Windows (Sound → your device → Configure), then reopen Soundstage.

License

MIT. Built with NAudio, WebView2, and Hardcodet NotifyIcon.