I built the system-wide equalizer macOS never shipped

The itch

macOS has no system-wide equalizer and no per-app volume mixer. The EQ in the Music app affects Music only. Everything else your Mac plays, YouTube, Zoom, games, Spotify, comes out exactly as it was mixed, whether or not that suits your headphones, your speakers, or your hearing. The classic workarounds are a browser-extension EQ that fixes one tab, or a stack of Aggregate Devices plus a loopback driver that breaks on the next macOS update.

What I built

EQBase is a native macOS app that captures everything the Mac plays and runs it through one processing chain before it reaches your output: EQ from 3 controls up to a 24-band parametric, headphone correction curves for 8,666 measured models, per-app volume and per-app EQ, per-app output routing, Audio Unit hosting, recording, room measurement, loudness compensation.

The hard part was not the DSP, it was trust

Software that sits in front of everything you hear is exactly the software you do not want quietly degrading your music. So the bar I set was: prove it, do not claim it.

• Zero added latency to the direct signal. The two opt-in exceptions are disclosed inside the app.

• Bit-perfect when flat. With every control flat or bypassed, output samples are mathematically identical to input samples, and the app verifies that continuously against the live audio and shows you the result. Anything it cannot prove, it withholds.

• No driver by default. Setup is one system permission: no admin password, no kernel extension.

Business model

Freemium, sold direct. The free tier has no time limit: 10-band EQ, all 8,600+ headphone corrections, volume boost, presets that switch by device. Pro is $4.99/month, $39.99/year, or $79.99 once for lifetime, with a 14-day no-questions refund. No account, works offline.

Where I am

The first public build went out on August 5. Ten releases later it is at v1.4.5, almost all of it from acting on early user feedback.

If you are on macOS 14 or later, the free tier is at https://eqbase.app. I would genuinely value feedback from this crowd, and I am happy to go deep on the Core Audio internals in the comments.